ORCID Profile
0000-0002-9152-0786
Current Organisation
University of Leeds
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Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.WATRES.2014.12.023
Abstract: Stimuli-responsive hydrogels were recently proposed for energy-saving forward osmosis (FO) process. However, their low water flux and dewatering ability for reuse make them less attractive for industrial desalination process. In this work, the co-polymer microgels of N-isopropylacrylamide and acrylic acid with different mixing ratios were synthesized using surfactant-free emulsion polymerization to produce submicron-size hydrogels with high surface area and fast swelling-deswelling response. The microgels were employed as draw agents in a laboratory scale FO desalination system. The microgel-based FO process performed a high water flux up to 23.8 LMH and high water recovery ability of 72.4%. In addition, we explored a new conductivity measurement method to online analyze water flux of the FO system. This on-line conductivity analysis approach appeared to be an accurate and efficient method for evaluating microgel-based FO desalination performance. Our experimental data revealed that the stimuli-responsive microgel was an efficient draw agent for FO desalination.
Publisher: American Chemical Society (ACS)
Date: 16-12-2006
DOI: 10.1021/JP066490K
Abstract: The viscosity of hydrophobic ethoxylated urethane (HEUR) solution decreased in the presence of alpha-CD or m-beta-CD however their interactions were quite different. When the alpha-CD/hydrophobe molar ratio exceeded 5.0, the viscosity was close to that of a PEO solution of similar molecular weight. Oscillatory shear indicated that the mechanically active chains in HEUR solution decreased with the addition of alpha-CD. This agreed with the hypothesis that alpha-CD formed an inclusion complex with the hydrophobic moiety of the HEUR polymer, thereby destroying the transient hydrophobic associative network. The viscosity/temperature relationship of the alpha-CD/HEUR system (for HEUR with 70% of the PEO chains capped at both ends) did not obey the Arrhenius relationship for alpha-CD/hydrophobe molar ratio in the range 0.8-5.0. The low shear viscosity increased with increasing temperature at molar ratio of 1.0, and this was attributed to the competitive complexation of the alpha-CD/hydrophobe and the alpha-CD/PEO chain. Increasing temperature favored alpha-CD/PEO complexation. Comparison between the behavior of alpha-CD/HEUR and m-beta-CD/HEUR resulting from the different binding characteristics was discussed.
Publisher: Wiley
Date: 26-10-2018
DOI: 10.1002/JBM.A.36479
Abstract: Tumor spheroids are considered to be effective in drug screening and evaluation. Three-dimensional scaffold-based cell culture becomes very promising in producing multicellular spheroids. Different from other approaches, 3D scaffolds mimic in vivo cellular microenvironment which encourages intercellular and extracellular interactions. The properties of the cellular microenvironment include the surface wettability, chemistry, and charge of the scaffolds which may influence cell attachment, proliferation as well as migration and these properties are essential for multicellular spheroids formation. Through co-polymerization with different carboxylic acids, we demonstrate that the surface charge density and hydrophobicity of the microenvironment have a great impact on the tumor spheroids formation progress and their size distribution. Our results show that a scaffold with a moderate negative charge density and a highly hydrophilic surface promotes cell proliferation, resulting in quicker and larger spheroids formation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2899-2909, 2018.
Publisher: Wiley
Date: 08-02-2018
Abstract: Research into efficient synthesis, fundamental properties, and potential applications of phosphorene is currently the subject of intense investigation. Herein, solution-processed phosphorene or few-layer black phosphorus (FL-BP) sheets are prepared using a microwave exfoliation method and used in photoelectrochemical cells. Based on experimental and theoretical (DFT) studies, the FL-BP sheets are found to act as catalytically active sites and show excellent electrocatalytic activity for triiodide reduction in dye-sensitized solar cells. Importantly, the device fabricated based on the newly designed cobalt sulfide (CoS
Publisher: Elsevier BV
Date: 02-2020
Publisher: American Chemical Society (ACS)
Date: 13-02-2004
DOI: 10.1021/LA0357559
Abstract: Isothermal titration calorimetry (ITC) is a sensitive research tool for examining the binding interactions between surfactant and polymer where the differential enthalpy during the binding process is monitored. In addition to the critical micelle concentration (cmc) and the micellization enthalpy (deltaHm), the effective micellar charge fraction (beta) of the ionic surfactant micellization process can also be determined from ITC thermograms. Poly(propylene glycol) (PPG) exhibits a lower critical solution temperature (LCST) ranging from 15 to 42 degrees C, depending on the molecular weights. We report, for the first time, the binding interactions between sodium dodecyl sulfate (SDS) and 1,000, 2,000 and 3,000 Da PPGs, where different binding mechanisms are in operation, depending on the temperature. At temperatures lower than the LCST, the binding interactions are similar to those of SDS and low molecular weight poly(ethylene glycol)s (MW < 3500 Da). At temperatures greater than the LCST, the binding interactions are dominated by direct solubilization of PPG chains into mixed micellar cores. At temperatures near the LCST, the binding interactions are controlled by the balance ofthe PPG solubilization at low SDS concentrations and polymer-induced micellization at high SDS concentrations.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR03869G
Abstract: A smart drug delivery system with non-destructive surface-enhanced Raman scattering tracing tags and targeted cancer-cell cytotoxicities is constructed.
Publisher: Wiley
Date: 10-10-2022
Abstract: Hydrogel electronics have attracted growing interest for emerging applications in personal healthcare management, human‐machine interaction, etc. Herein, a “doping then gelling” strategy to synthesize supramolecular PANI/PAA hydrogel with a specific strand entangled network is proposed, by doping the PANI with acrylic acid (AA) monomers to avoid PANI aggregation. The high‐density electrostatic interaction between PAA and PANI chains serves as a dynamic bond to initiate the strand entanglement, enabling PAA/PANI hydrogel with ultra‐stretchability (2830%), high breaking strength (120 kPa), and rapid self‐healing properties. Moreover, the PAA/PANI hydrogel‐based sensor with a high strain sensitivity (gauge factor = 12.63), a rapid responding time (222 ms), and a robust conductivity‐based sensing behavior under cyclic stretching is developed. A set of strain sensing applications to precisely monitor human movements is also demonstrated, indicating a promising application prospect as wearable devices.
Publisher: Springer Science and Business Media LLC
Date: 02-10-2010
DOI: 10.1007/S10856-010-4157-7
Abstract: The nanocomposites containing hydroxyapatite (HA) and biomacromolecules have attracted considerable research interest in implants, tissue scaffolds and drug controlled delivery. In this study, the N-carboxyethylchitosan/hydroxyapatite (NCECS/HA) nanoparticles were prepared by the ionic diffusion process in a controlled manner. The crystallization, particle size, size distribution and aggregation morphology of the NCECS/HA nanocomposites were dependent on the mole ratio of the glucosamine unit in NCECS to the Ca(2+). Fourier transform-infrared spectroscopic (FTIR) result indicated that there are chemical bonds formed between NCECS and HA. X-ray diffraction (XRD) analysis showed that the crystallization of HA in NCECS matrix was significantly retarded. Transmission electron microscopy (TEM) results revealed that NCECS/HA nanocomposites have the spherical morphology with the diameter ranging from 10 to 40 nm. The NCECS mineralization is driven by the self-assembly of NCECS and HA. These NCECS/HA nanocomposites have potential applications as the carrier for the controlled delivery of growth factors and drugs.
Publisher: American Chemical Society (ACS)
Date: 23-12-2011
DOI: 10.1021/BM201380E
Abstract: Chitosan shows good biocompatibility and biodegradability, but the poor water solubility and low transfection efficiency hinder its applications as a gene delivery vector. We here report the detailed synthesis and characterization of a novel holytical chitosan derivative, N-imidazolyl-O-carboxymethyl chitosan (IOCMCS), used for high performance gene delivery. After chemical modification, the solubility of the resulting polymer is enhanced, and the polymer is soluble in a wide pH range (4-10). Gel electrophoresis study reveals the strong binding ability between plasmid DNA and the IOCMCS. Moreover, the IOCMCS does not induce remarkable cytotoxicity against human embryonic kidney (HEK293T) cells. The cell transfection results with HEK293T cells using the IOCMCS as gene delivery vector demonstrate the high transfection efficiency, which is dependent on the degree of imidazolyl substitution. Therefore, the IOCMCS is a promising candidate as the DNA delivery vector in gene therapy due to its high solubility, high gene binding capability, low cytotoxicity, and high gene transfection efficiency.
Publisher: Wiley
Date: 12-2002
Publisher: American Chemical Society (ACS)
Date: 13-09-2006
DOI: 10.1021/JP061438+
Abstract: The micellization of sodium dodecyl sulfate (SDS) in different glycol-water solvent mixtures was studied using the isothermal titration calorimetric (ITC) technique. At the same time, microcalorimetric titrations were also carried out to monitor the binding interaction of SDS and poly(ethylene oxide) (PEO) in the presence of different cosolvents. The demicellization of SDS in mixtures of water and cosolvents is different from that in water due to the reduction in solvent polarity and charge interaction of surfactants. The critical micelle concentration (cmc) first decreases with the addition of a small amount of cosolvents and then increases at higher cosolvent concentrations. The thermodynamics of surfactant micellization can be analyzed using the solubility parameters of solvent mixtures. For the binding interaction between SDS and PEO in different solvent mixtures, the dehydration process at low SDS concentrations is replaced by the chain solubilization process with decreasing solvent polarity. With further reduction in the solvent polarity, the binding interaction between SDS and PEO becomes weak and no aggregates can be formed beyond a certain glycol concentration. The binding interaction between SDS and PEO in different solvent mixtures was analyzed and ascribed to the effects of PEO solubility and hydrophobicity of SDS.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B921770C
Publisher: Elsevier BV
Date: 07-2005
DOI: 10.1016/J.COLSURFB.2005.04.009
Abstract: O-Carboxymethylchitosan (OCMCS) is a kind of biocompatible derivatives of chitosan whose water solubility is strongly dependent on the degree of carboxymethylation. The OCMCS with 100 carboxymethyl groups and 75 amino groups per 100 anhydroglucosamine units of OCMCS was synthesized by the reaction of chitosan and monochloroacetic. When OCMCS was dissolved in water, its solution was neutral and OCMCS behaved like a weak polyanionic polyeclectrolyte because most of carboxylic groups were not dissociated in neutral aqueous solution. The aggregation behavior of OCMCS in aqueous solution was studied by surface tensiometry, steady-state fluorescence spectroscopy and viscometry. The critical aggregation concentration (cac) of OCMCS was determined to be between 0.042 mg/ml and 0.050 mg/ml. The possible aggregation mechanism of OCMCS in water was elucidated.
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 09-2016
Publisher: Wiley
Date: 19-12-2017
Publisher: Elsevier BV
Date: 2017
Publisher: Wiley
Date: 14-07-2015
Publisher: Wiley
Date: 02-06-2014
Abstract: A new class of highly efficient oxygen evolution catalysts has been synthesized through the self-assembly of graphitic carbon nitride nanosheets and carbon nanotubes, driven by π-π stacking and electrostatic interactions. Remarkably, the catalysts exhibit higher catalytic oxygen evolution activity and stronger durability than Ir-based noble-metal catalysts and display the best performance among the reported nonmetal catalysts. This good result is attributed to the high nitrogen content and the efficient mass and charge transfer in the porous three-dimensional nanostructure.
Publisher: The Royal Society
Date: 27-07-2011
Abstract: Stem cell therapy is an emerging technique which is being translated into treatment of degenerated tissues. However, the success of translation relies on the stem cell lineage commitment in the degenerated regions of interest. This commitment is precisely controlled by the stem cell microenvironment. Engineering a biomimetic three-dimensional microenvironment enables a thorough understanding of the mechanisms of governing stem cell fate. We review the in idual microenvironment components, including soluble factors, extracellular matrix, cell–cell interaction and mechanical stimulation. The perspectives in creating the biomimetic microenvironments are discussed with emerging techniques.
Publisher: Informa UK Limited
Date: 04-2022
Publisher: Wiley
Date: 23-05-2013
DOI: 10.1002/APP.37670
Publisher: Elsevier BV
Date: 12-2000
Publisher: Informa UK Limited
Date: 2009
Publisher: American Chemical Society (ACS)
Date: 28-08-2021
Publisher: American Chemical Society (ACS)
Date: 07-04-2021
Abstract: Human ferritin is regarded as an attractive and promising vaccine platform because of its uniform structure, good plasticity, and desirable thermal and chemical stabilities. Besides, it is biocompatible and presumed safe when used as a vaccine carrier. However, there is a lack of knowledge of how different antigen insertion sites on the ferritin nanocage impact the resulting protein stability and performance. To address this question, we selected Epstein-Barr nuclear antigen 1 as a model epitope and fused it at the DNA level with different insertion sites, namely, the N- and C-termini of ferritin, to engineer proteins E1F1 and F1E1, respectively. Protein properties including hydrophobicity and thermal, pH, and chemical stability were investigated both by molecular dynamics (MD) simulation and by experiments. Both methods demonstrate that the insertion site plays an important role in protein properties. The C-terminus insertion (F1E1) leads to a less hydrophobic surface and more tolerance to the external influence of high temperature, pH, and high concentration of chemical denaturants compared to N-terminus insertion (E1F1). Simulated protein hydrophobicity and thermal stability by MD were in high accordance with experimental results. Thus, MD simulation can be used as a valuable tool to engineer nanovaccine candidates, cutting down costs by reducing the experimental effort and accelerating vaccine design.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Elsevier BV
Date: 06-2016
Publisher: American Chemical Society (ACS)
Date: 07-1997
DOI: 10.1021/JE960235J
Publisher: American Chemical Society (ACS)
Date: 10-11-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2PY20494K
Publisher: Wiley
Date: 03-03-2020
DOI: 10.1002/JRS.5863
Publisher: Elsevier BV
Date: 05-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B820044K
Publisher: American Chemical Society (ACS)
Date: 16-04-2003
DOI: 10.1021/LA026992Z
Publisher: Wiley
Date: 19-03-2022
Abstract: One of the key challenges in developing gel‐based electronics is to achieve a robust sensing performance, by overcoming the intrinsic weaknesses such as unwanted swelling induced deformation, signal distortion caused by dehydration, and large hysteresis in sensing signal. In this work, a structural gel composite (SGC) approach is presented by encapsulating the conductive hydrogel/MXene with a lipid gel (Lipogel) layer through an in situ polymerization. The hydrophobic Lipogel coating fulfills the SGC with a unique anti‐swelling property at an aqueous environment and excellent dehydration feature at an open‐air, thus leading to long‐term ultra‐stability (over 90 days) and durability (over 2000 testing cycles) for underwater mechanosensing applications. As a result, the SGC based mechanoreceptor demonstrates high and stable sensitivity (GF of 14.5). Moreover, several SGC based conceptual sensors with high sensitivity are developed to unveil their profound potential in underwater monitoring of human motions, waterproof anti‐counterfeiting application, and tactile trajectory tracking.
Publisher: Wiley
Date: 22-11-2011
DOI: 10.1002/BTPR.720
Abstract: Sertoli cells (SCs) have been described as the "nurse cells" of testis to provide essential growth factors and to create a proper environment for the development of other cells (e.g., germinal and neural stem cell). However, the physiological functions of the SCs obtained from different culture conditions are different in a coculturing system, and thus the optimal SC culturing condition should be investigated in vitro. In this paper, primary Sertoli cells were isolated from a 12-day-old mouse and expanded in two different culture conditions: a two dimensional (2D) plastic tissue disc and a three dimensional (3D) microcarrier culture system. They were then cocultured with neural stem cells (NSCs) isolated from 14-day-old mouse embryos. The metabolic activities of SCs(2D) (SCs in 2D) and SCs(3D) (SCs in 3D) and the amount of proteins secreted from two culturing systems were compared. The results show that the metabolic activity and the amount of secreted proteins from SCs(3D) were higher than both from SCs(2D). Three coculturing groups: NSCs+SC(2D), NSCs+SC(3D), and NSCs +SC-conditioned medium (SCCM, control group) were also compared regarding cell morphology and the numbers of neurons, neural outgrowths and neurospheres. The quantity of neurons, neural outgrowths and neurospheres were the highest in the NSCs+SC(3D) group. SCs cultured in the 3D system had a strong trophic effect on NSCs and enhanced their survival and growth. Besides, the mRNA of trophic and nutritive factors such as Glial-cell-line-derived neurotrophic factor (GDNF) and Interleukin-1 α (IL-1 α) secreted by the SCs from both 2D and 3D culture system were analyzed by real time-PCR and gel assay. The mRNA transcription of GDNF and IL-1α is more apparent in the 3D culture system than that from the 2D one. The coculturing system of NSCs+SC(3D) is a promising candidate for future neural stem cell transplantation.
Publisher: American Chemical Society (ACS)
Date: 21-03-2007
DOI: 10.1021/MA0622884
Publisher: American Chemical Society (ACS)
Date: 18-02-2005
DOI: 10.1021/JP045413R
Abstract: A well-defined, water-soluble, pH and temperature stimuli-responsive [60]fullerene (C(60)) containing holytic block copolymer of poly((methacrylic acid)-block-(2-(dimethylamino)ethyl methacrylate))-block-C(60) (P(MAA-b-DMAEMA)-b-C(60)) was synthesized by the atom transfer radical polymerization (ATRP) technique. The self-assembly behavior of the C(60) containing poly holyte in aqueous solution was characterized by potentiometric and conductometric titration, dynamic light scattering (DLS), and transmission electron microscopy. This hiphilic mono-C(60) end-capped block copolymer shows enhanced solubility in aqueous medium at room and elevated temperatures and at low and high pH but phase separates at intermediate pH between 5.4 and 8.8. The self-assembly of the copolymer is different from that of P(MAA-b-DMAEMA). Examination of the association behavior using DLS revealed the coexistence of unimers and aggregates at low pH at all temperatures studied, with the association being driven by the balance of hydrophobic and electrostatic interactions. Unimers and aggregates of different microstructures are also observed at high pH and at temperatures below the lower critical solution temperature (LCST) of PDMAEMA. At high pH and at temperatures above the LCST of PDMAEMA, the formation of micelles and aggregates coexisting in solution is driven by the combination of hydrophobic, electrostatic, and charge-transfer interactions.
Publisher: Wiley
Date: 2001
DOI: 10.1002/1521-3935(20010101)202:2<335::AID-MACP335>3.0.CO;2-H
Publisher: Elsevier BV
Date: 11-2016
Publisher: American Chemical Society (ACS)
Date: 28-12-1999
DOI: 10.1021/MA990887N
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.JBIOTEC.2016.02.014
Abstract: The nanoenvironment of nanobiocatalysts, such as local hydrophobicity, pH and charge density, plays a significant role in optimizing the enzymatic selectivity and specificity. In this study, Kluyveromyces lactis β-galactosidase (Gal) was assembled onto polystyrene nanofibers (PSNFs) to form PSNF-Gal nanobiocatalysts. We proposed that local hydrophobicity on the nanofiber surface could expel water molecules so that the transgalactosylation would be preferable over hydrolysis during the bioconversion of lactose, thus improve the galacto-oligosaccharides (GOS) yield. PSNFs were fabricated by electro-spinning and the operational parameters were optimized to obtain the nanofibers with uniform size and ordered alignment. The resulting nanofibers were functionalized for enzyme immobilization through a chemical oxidation method. The functionalized PSNF improved the enzyme adsorption capacity up to 3100 mg/g nanofiber as well as enhanced the enzyme stability with 80% of its original activity. Importantly, the functionalized PSNF-Gal significantly improved the GOS yield and the production rate was up to 110 g/l/h in comparison with 37 g/l/h by free β-galactosidase. Our research findings demonstrate that the localized nanoenvironment of the PSNF-Gal nanobiocatalysts favour transgalactosylation over hydrolysis in lactose bioconversion.
Publisher: Elsevier BV
Date: 2006
DOI: 10.1016/J.COLSURFB.2005.11.020
Abstract: The effects of salt with different valences (NaCl, CaCl2 and CrCl3) on the aggregation of O-carboxylmethylchitosan (OCMCS) in dilute aqueous solution were investigated using viscometry, dynamic laser light scattering (DLS) and atomic force microscopy (AFM). With increasing OCMCS concentration beyond a critical aggregation concentration (cac) of approximately 0.045 g/l, the aggregation of OCMCS appears in solution. The driving forces of the OCMCS aggregation are intermolecular hydrogen bond, hydrophobic interaction and electrostatic repulsion. The OCMCS aggregation behavior strongly depends on the valence of salt. When NaCl is added, the aggregate size increases with NaCl concentration. When CaCl2 or CrCl3 is added to a given OCMCS concentration, there exists a critical concentration each of Ca2+ and Cr3+. Before the critical concentration, the aggregates decrease in size with increasing salt concentration due to the intra-aggregate complexation while after the critical concentration, the size of the aggregates increases with salt concentration due to the inter-aggregate complexation. Moreover, the effect of Cr3+ on the OCMCS aggregation is greater than that of Ca2+. The formation of the intra-aggregate complexation is found to be a kinetic process and the aggregate size decreases with time the formation of the inter-aggregate complexation is also kinetic where the aggregate size increases with time. The aggregates dominated by the intra-aggregate complexation are small, compact and spherical, while the aggregates dominated by the inter-aggregate complexation show the big, compact and spherical morphology.
Publisher: Wiley
Date: 18-11-2017
Abstract: A robust solution phase ligand exchange system for lead sulfide (PbS) quantum dots (QDs) in the presence of Pb-thiolate ligands is presented that can better preserve the excitonic absorption and emission features as compared to the conventional ligands. The photoluminescence after ligand exchange of PbS QDs with Pb-thiolate ligand is preserved up to 78% of the original oleate capped PbS QDs.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.MSEC.2015.10.043
Abstract: Poly (N-isopropylacrylamide) (PNIPAAm) is a thermosensitive polymer with various biomedical applications. We examined molecular weight (MW)-dependent cytotoxicity of PNIPAAm. Our results indicated that low-MW PNIPAAm (degree of polymerization (DP)=35) is inherently toxic to cells. Moderate-MW PNIPAAms with their DP between 100 and 200 are non-cytotoxic. When cells are seeded on top of a polymer-coated surface, PNIPAAm with a higher MW (DP=400) shows non/low cytotoxicity, while when monolayer cells are exposed to the polymer solution, cell viability drops drastically. This may be due to lack of nutrient and oxygen rather than intrinsic toxicity of the polymer.
Publisher: Wiley
Date: 14-08-2014
Abstract: Composition-adjustable spinel-type metal oxides, Mnx Co3-x O4-δ (x=0.8-1.4), were synthesized in ethanol solutions by a rapid inorganic self-templating mechanism using KCl nanocrystals as the structure-directing agent. The Mnx Co3x O4δ materials showed ultrahigh oxygen evolution activity and strong durability in alkaline solutions, and are capable of delivering a current density of 10 mA cm(-2) at 1.58 V versus the reversible hydrogen electrode in 0.1 M KOH solution, which is superior in comparison to IrO2 catalysts under identical experimental conditions, and comparable to the most active noble-metal and transition-metal oxygen evolution electrocatalysts reported so far. The high performance for catalytic oxygen evolution originates from both compositional and structural features of the synthesized materials. The moderate content of Mn doping into the spinel framework led to their improved electronic conductivity and strong oxidizing ability, and the well-developed porosity, accompanied with the high affinity between OH(-) reactants and catalyst surface, contributed to the smooth mass transport, thus endowing them with superior oxygen evolution activity.
Publisher: American Scientific Publishers
Date: 04-2007
DOI: 10.1166/JNN.2007.456
Abstract: Due to the theoretical importance and potential applications of fullerene, numerous fullerene derivatives have been developed to enhance its solubility and processability. This article provides an overview on fullerene containing polymers, from synthesis to their physicochemical properties in solution. Due to the unique chemical structure of fullerene, different fullerene containing polymeric architecture can be synthesized through various kinds of conjugating techniques, where fullerene can be located either on the backbone or the branch chain. Recently, the successful development of azido coupling and atom transfer radical addition (ATRA) makes it possible to synthesize "controlled" and well-defined fullerene containing polymers. Experimental results indicated that fullerene containing polymers not only increase the solubility of fullerene in solution, but also retain the conjugating properties of fullerene molecules. By blocking well-defined functional polymers onto fullerene molecules, different types of stimuli-responsive hiphilic systems can be achieved. However, the large bulk volume and high hydrophobicity of fullerene gives rise to the large aggregates with different morphologies produced in solution, which can be tuned by changing external stimuli, such as pH, temperature, salt, and co-solvents. Interestingly, fullerene containing anionic polymers could induce the formation nano-scale fractal pattern, but not fullerene containing cationic polymers, which is evident from morphological studies.
Publisher: American Chemical Society (ACS)
Date: 12-10-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1SM06262J
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR03089G
Abstract: Composite materials combining nitrogen-doped carbon (NC) with active species represent a paramount breakthrough as alternative catalysts to Pt for the oxygen reduction reaction (ORR) due to their competitive activity, low cost and excellent stability. In this paper, a simple strategy is presented to construct graphene oxide-polydopamine (GD) based carbon nanosheets. This approach does not need to modify graphene and use any catalyst for polymerization under ambient conditions, and the obtained carbon nanosheets possess adjustable thicknesses and uniform mesoporous structures without using any template. The thickness of GD hybrids and the carbonization temperature are found to play crucial roles in adjusting the microstructure of the resulting carbon nanosheets and, accordingly their ORR catalytic activity. The optimized carbon nanosheet generated by a GD hybrid of 5 nm thickness after 900 °C carbonization exhibits superior ORR activity with an onset potential of -0.07 V and a kinetic current density of 13.7 mA cm(-2) at -0.6 V. The unique mesoporous structure, high surface areas, abundant defects and favorable nitrogen species are believed to significantly benefit the ORR catalytic process. Furthermore, it also shows remarkable durability and excellent methanol tolerance outperforming those of commercial Pt/C. In view of the physicochemical versatility and structural tunability of polydopamine (PDA) materials, our work would shed new light on the understanding and further development of PDA-based carbon materials for highly efficient electrocatalysts.
Publisher: American Chemical Society (ACS)
Date: 06-10-2009
DOI: 10.1021/JA9052009
Publisher: American Chemical Society (ACS)
Date: 03-02-2021
Publisher: Elsevier BV
Date: 2015
Publisher: MDPI AG
Date: 11-11-2021
DOI: 10.3390/BIOS11110444
Abstract: Diverse drug loading approaches for human heavy-chain ferritin (HFn), a promising drug nanocarrier, have been established. However, anti-tumor drug loading ratio and protein carrier recovery yield are bottlenecks for future clinical application. Mechanisms behind drug loading have not been elaborated. In this work, a thermally induced drug loading approach was introduced to load anti-tumor drug doxorubicin hydrochloride (DOX) into HFn, and 2 functionalized HFns, HFn-PAS-RGDK, and HFn-PAS. Optimal conditions were obtained through orthogonal tests. All 3 HFn-based proteins achieved high protein recovery yield and drug loading ratio. Size exclusion chromatography (SEC) and transmission electron microscopy (TEM) results showed the majority of DOX loaded protein (protein/DOX) remained its nanocage conformation. Computational analysis, molecular docking followed by molecular dynamic (MD) simulation, revealed mechanisms of DOX loading and formation of by-product by investigating non-covalent interactions between DOX with HFn subunit and possible binding modes of DOX and HFn after drug loading. In in vitro tests, DOX in protein/DOX entered tumor cell nucleus and inhibited tumor cell growth.
Publisher: Elsevier BV
Date: 04-2003
Publisher: American Chemical Society (ACS)
Date: 13-10-2001
DOI: 10.1021/JP0110354
Publisher: Society of Rheology
Date: 03-2009
DOI: 10.1122/1.3059563
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 11-2003
Publisher: Elsevier BV
Date: 05-2020
Publisher: Inderscience Publishers
Date: 2007
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TA06748D
Abstract: Highly ordered ZnMnO 3 nanotube arrays show high cycling performance and rate capability when used as an anode material for lithium-ion batteries.
Publisher: Elsevier BV
Date: 04-2016
Publisher: Elsevier BV
Date: 09-2016
Publisher: Wiley
Date: 21-02-2019
Abstract: Quantum dots (QDs) of lead chalcogenides (e.g. PbS, PbSe, and PbTe) are attractive near-infrared (NIR) active materials that show great potential in a wide range of applications, such as, photovoltaics (PV), optoelectronics, sensors, and bio-electronics. The surface ligand plays an essential role in the production of QDs, post-synthesis modification, and their integration to practical applications. Therefore, it is critically important that the influence of surface ligands on the synthesis and properties of QDs is well understood for their applications in various devices. In this Review we elaborate the application of colloidal synthesis techniques for the preparation of lead chalcogenide based QDs. We specifically focus on the influence of surface ligands on the synthesis of QDs and their solution-phase ligand exchange. Given the importance of lead chalcogenide QDs as potential light harvesters, we also pay particular attention to the current progress of these QDs in photovoltaic applications.
Publisher: American Chemical Society (ACS)
Date: 26-05-2009
DOI: 10.1021/LA900563Y
Abstract: The influence of hydroxypropyl guar (HPG), with and without boric acid, on dodecyltrimethyl ammonium bromide (DTAB) micellization was characterized by surface tension measurements, isothermal titration calorimetry, and small-angle neutron scattering. Although HPG is a nonionic water-soluble polymer, borate ions form weak bonds with HPG, transforming it into an anionic polyelectrolyte, HPG-borate. Surprisingly, the three independent measurements showed that HPG-borate does not promote DTAB micellization or phase separation normally seen when mixing oppositely charged polyelectrolytes and surfactants. However, the neutron scattering results suggested that HPG-borate binds to and flocculates existing DTAB micelles. The unusual behavior of HPG-borate with DTAB was underscored by showing that carboxymethyl guar (CMG) formed precipitates with DTAB.
Publisher: MDPI AG
Date: 16-02-2022
DOI: 10.3390/BIOS12020121
Abstract: Suspension microsphere immunoassays are rapidly gaining attention in multiplex bioassays. Accurate detection of multiple analytes from a single measurement is critical in modern bioanalysis, which always requires complex encoding systems. In this study, a novel bioassay with Raman-coded antibody supports (polymer microbeads with different Raman signatures) and surface-enhanced Raman scattering (SERS)-coded nanotags (organic thiols on a gold nanoparticle surface with different SERS signatures) was developed as a model fluorescent, label-free, bead-based multiplex immunoassay system. The developed homogeneous immunoassays included two surface-functionalized monodisperse Raman-coded microbeads of polystyrene and poly(4-tert-butylstyrene) as the immune solid supports, and two epitope modified nanotags (self-assembled 4-mercaptobenzoic acid or 3-mercaptopropionic acid on gold nanoparticles) as the SERS-coded reporters. Such multiplex Raman/SERS-based microsphere immunoassays could selectively identify specific paratope–epitope interactions from one mixture s le solution under a single laser illumination, and thus hold great promise in future suspension multiplex analysis for erse biomedical applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TB00376A
Abstract: hMSCs derived from normal donors induced multi-lineage differentiation within thermosensitive poly( N -isopropylacrylamide- co -acrylic acid) microgel-formed 3D constructs.
Publisher: Elsevier BV
Date: 10-2006
Publisher: American Chemical Society (ACS)
Date: 29-06-2017
Abstract: Dual heteroatom-doped carbon materials are efficient electrocatalysts via a synergistic effect. With nitrogen as the primary dopant, boron, sulfur, and phosphorus can be used as secondary elements for co-doped carbons. However, evaluation and analysis of the promotional effect of B, P, and S to N-doped carbons has not been widely researched. Here we report a robust platform that is constructed through polydopamine to prepare N,B-, N,P-, and N,S-co-doped carbon nanosheets, characterized by similar N species content and efficient B, P, and S doping. Systematic investigation reveals S to have the greatest promotional effect in hydrogen evolution reactions (HER) followed by P and that B decreases the activity of N-doped carbons. Experimental and theoretical analyses show the secondary heteroatom promotional effect is impacted by the intrinsic structures and extrinsic surface areas of both materials, i.e., electronic structures exclusively determine the catalytic activity of active sites, while large surface areas optimize apparent HER performance.
Publisher: Elsevier BV
Date: 09-2009
Publisher: Elsevier BV
Date: 11-2004
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TA01672F
Publisher: MDPI AG
Date: 09-04-2021
DOI: 10.3390/PHARMACEUTICS13040521
Abstract: Ferritin, one of the most investigated protein nanocages, is considered as a promising drug carrier because of its advantageous stability and safety. However, its short half-life and undesirable tumor targeting ability has limited its usage in tumor treatment. In this work, two types of functional peptides, half-life extension peptide PAS, and tumor targeting peptide RGDK (Arg-Gly-Asp-Lys), are inserted to human heavy-chain ferritin (HFn) at C-terminal through flexible linkers with two distinct enzyme cleavable sites. Structural characterizations show both HFn and engineered HFns can assemble into nanoparticles but with different apparent hydrodynamic volumes and molecular weights. RGDK peptide enhanced the internalization efficiency of HFn and showed a significant increase of growth inhibition against 4T1 cell line in vitro. Pharmacokinetic study in vivo demonstrates PAS peptides extended ferritin half-life about 4.9 times in Sprague Dawley rats. RGDK peptides greatly enhanced drug accumulation in the tumor site rather than in other organs in biodistribution analysis. Drug loaded PAS-RGDK functionalized HFns curbed tumor growth with significantly greater efficacies in comparison with drug loaded HFn.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6CP02119K
Abstract: In this study, we present a detailed understanding on synthesis mechanism of PbS QDs so as to provide guidance for future QDs synthesis.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2SM25407G
Publisher: Wiley
Date: 03-10-2005
DOI: 10.1002/POLB.20588
Publisher: American Chemical Society (ACS)
Date: 07-01-2005
DOI: 10.1021/MA0480547
Publisher: Elsevier BV
Date: 02-2019
Publisher: Elsevier BV
Date: 07-2014
DOI: 10.1016/J.BIOMATERIALS.2014.03.051
Abstract: To create advanced functional nanocarriers for achieving excellent gene delivery performance, fluorescence label-free hybridized dendrimer-like silica nanocarriers (HPSNs-AC-PEI) were developed by using the endosomal pH and cytoplasmic glutathione (GSH) responsive autofluorescent acetaldehyde-modified-cystine (AC) to link non-toxic low molecular weight branched polyethyleneimine (PEI) onto amino-functionalized dendrimer-like silica nanoparticles with hierarchical pores (HPSNs-NH2). The specific microstructure of this hybridized nanocarrier makes it not only show low cytotoxicity and high gene loading capability, but also display high gene transfection efficiency. The cleavage of disulfide bonds caused by GSH facilitates plasmid DNA (pDNA) release. Moreover, the pH and GSH controlled gene delivery profile can be real-time tracked using the autofluorescence of HPSNs-AC-PEI.
Publisher: Elsevier BV
Date: 11-2013
Publisher: Wiley
Date: 06-03-2018
Publisher: American Chemical Society (ACS)
Date: 15-10-2004
DOI: 10.1021/LA0480843
Abstract: Well-defined water-soluble pH-responsive [60]fullerene (C60) containing poly(methacrylic acid) (PMAA-b-C60) was synthesized using the atom transfer radical polymerization technique. By varying pH and salt concentration, different types of fractal patterns at nano- to microscopic dimensions were observed for negatively charged PMAA-b-C60, while such structure was not observed for positively charged poly(2-dimethylaminoethyl methacrylate)-b-C60. We demonstrated that negatively charged fullerene containing polymeric systems can serve as excellent nanotemplates for the controlled growth of inorganic crystals at the nano- to micrometer length scale, and the possible mechanism was proposed.
Publisher: Wiley
Date: 02-10-2013
Abstract: A new strategy for promoting endoplasmic gene delivery and nucleus uptake is proposed by developing intracellular microenvironment responsive biocompatible polymers. This delivery system can efficiently load and self-assemble nucleic acids into nano-structured polyplexes at a neutral pH, release smaller imidazole-gene complexes from the polymer backbones at intracellular endosomal pH, transport nucleic acids into nucleus through intracellular environment responsive multiple-stage gene delivery, thus leading to a high cell transfection efficiency.
Publisher: Wiley
Date: 08-07-2016
DOI: 10.1002/JBM.A.35810
Abstract: Providing a controllable and definable three-dimensional (3D) microenvironment for chondrogenic differentiation of mesenchymal stem cells (MSCs) remains a great challenge for cartilage tissue engineering. In this work, poly(N-isopropylacrylamide) (PNIPAAm) polymers with the degrees of polymerization of 100 and 400 (NI100 and NI400) were prepared and the polymer solutions were introduced into the preprepared chitosan porous scaffolds (CS) to form hybrids (CSNI100 and CSNI400, respectively). SEM images indicated that the PNIPAAm gel partially occupied chitosan pores while the interconnected porous structure of chitosan was preserved. MSCs were incorporated within the hybrid and cell proliferation and chondrogenic differentiation were monitored. After 7-day incubation of the cell-laden constructs in a growth medium, the cell viability in CSNI100 and CSNI400 were 54 and 108% higher than that in CS alone, respectively. Glycosaminoglycan and total collagen contents increased 2.6- and 2.5-fold after 28-day culture of cell-laden CSNI400 in the chondrogenic medium. These results suggest that the hybrid structure composed of the chitosan porous scaffold and the well-defined PNIPAAm hydrogel, in particular CSNI400, is suitable for 3D stem cell culture and cartilage tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2764-2774, 2016.
Publisher: Springer Science and Business Media LLC
Date: 06-2021
DOI: 10.1007/S10853-021-05852-Y
Abstract: Silver orthophosphate (Ag 3 PO 4 ) is an attractive photocatalytic catalyst for disinfection and degradation, but its instability arising from silver release generates significant environmental issue. Aiming to develop a highly efficient and environmental-friendly catalyst, we synthesized Ag 3 PO 4 nanoparticle incorporated hierarchical porous silica (Ag 3 PO 4 @ h -SiO 2 ) as a novel high-performance photocatalytic catalyst without observed silver release. Brain-like hierarchical porous SiO 2 ( h -SiO 2 ) brings a scaffold support with high surface areas, and the h -SiO 2 surface modified thiols are able to anchor in situ formed 10 nm Ag 3 PO 4 to eliminate silver release. Systematic investigations revealed that because of its structural advantages, Ag 3 PO 4 @ h -SiO 2 show excellent disinfection and degradation ability under visible-light irradiation and stable characteristics without obviously observed silver leaching during photo-oxidation operation. In-depth scavenger study reveals Ag 3 PO 4 @ h -SiO 2 as an effective semiconducting photocatalyst stimulates the production of photo-generated reactive species, which dominate its distinguished disinfection performance via photo-oxidation. Ag 3 PO 4 are anchored to thiol modified hierarchical porous SiO 2 to produce a visible-light responsive photocatalyst of Ag 3 PO 4 @h-SiO 2 . The enhanced catalytic sites and surface areas promote pathogen disinfection, and the structure advantages minimize silver release to environment. Both H 2 O 2 and holes being generated in photocatalysis dominate overall disinfection activity.
Publisher: American Chemical Society (ACS)
Date: 16-05-2003
DOI: 10.1021/LA0340652
Publisher: Wiley
Date: 21-02-2019
Publisher: American Chemical Society (ACS)
Date: 29-08-2001
DOI: 10.1021/MA010329K
Publisher: MDPI AG
Date: 06-01-2020
Abstract: Molecular distribution, structural conformation and catalytic activity at the interface between enzyme and its immobilising support are vital in the enzymatic reactions for producing bioproducts. In this study, a nanobiocatalyst assembly, β-galactosidase immobilized on chemically modified electrospun polystyrene nanofibers (PSNF), was synthesized for converting lactose into galacto-oligosaccharides (GOS). Characterization results using scanning electron microscopy (SEM) and fluorescence analysis of fluorescein isothiocyanat (FITC) labelled β-galactosidase revealed homogenous enzyme immobilization, thin layer structural conformation and biochemical functionalities of the nanobiocatalyst assembly. The β-galactosidase/PSNF assembly displayed enhanced enzyme catalytic performance at a residence time of around 1 min in a disc-stacked column reactor. A GOS yield of 41% and a lactose conversion of 88% was achieved at the initial lactose concentration of 300 g/L at this residence time. This system provided a controllable contact time of products and substrates on the nanofiber surface and could be used for products which are sensitive to the duration of nanobiocatalysis.
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 2014
Publisher: Wiley
Date: 05-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA11699J
Abstract: Thermo-reversible microgels to culture and harvest uniform-sized tumour spheroids with a narrow size-distribution.
Publisher: American Chemical Society (ACS)
Date: 06-10-2015
Abstract: Perovskites show excellent specific catalytic activity toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solutions however, small surface areas of the perovskites synthesized by traditional sol-gel methods lead to low utilization of catalytic sites, which gives rise to poor Li-O2 batteries performance and restricts their application. Herein, a hierarchical mesporous/macroporous perovskite La0.5Sr0.5CoO3-x (HPN-LSC) nanotube is developed to promote its application in Li-O2 batteries. The HPN-LSC nanotubes were synthesized via electrospinning technique followed by postannealing. The as-prepared HPN-LSC catalyst exhibits outstanding intrinsic ORR and OER catalytic activity. The HPN-LSC/KB electrode displays excellent performance toward both discharge and charge processes for Li-O2 batteries, which enhances the reversibility, the round-trip efficiency, and the capacity of resultant batteries. The synergy of high catalytic activity and hierarchical mesoporous/macroporous nanotubular structure results in the Li-O2 batteries with good rate capability and excellent cycle stability of sustaining 50 cycles at a current density of 0.1 mA cm(-2) with an upper-limit capacity of 500 mAh g(-1). The results will benefit for the future development of high-performance Li-O2 batteries using hierarchical mesoporous/macroporous nanostructured perovskite-type catalysts.
Publisher: Wiley
Date: 17-12-2014
Abstract: Flexible non-metal oxygen electrodes fabricated from phosphorus-doped graphitic carbon nitride nano-flowers directly grown on carbon-fiber paper exhibit high activity and stability in reversibly catalyzing oxygen reduction and evolution reactions, which is a result of N, P dual action, enhanced mass/charge transfer, and high active surface area. The performance is comparable to that of the state-of-the-art transition-metal, noble-metal, and non-metal catalysts. Remarkably, the flexible nature of these oxygen electrodes allows their use in folded and rolled-up forms, and directly as cathodes in Zn-air batteries, featuring low charge/discharge overpotential and long lifetime.
Publisher: Wiley
Date: 19-08-2013
Abstract: Functionalized dendrimer-like hybrid silica nanoparticles with hierarchical pores are designed and synthesized. The unique structure, large surface area, and excellent biocompability render such materials attractive nanocarriers for the advanced delivery of various sized drugs and genes simultaneously.
Publisher: Wiley
Date: 21-10-2010
DOI: 10.1002/PC.20863
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA12215A
Abstract: Chitosan- g -poly( N -isopropylacrylamide) was synthesized as a stem cell mimicking microenvironment. Solubility and gel mechanical strength were optimised through manipulating the grafting parameters.
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.PHRS.2011.06.015
Abstract: In order to minimize the side effect of cancer chemotherapy, a novel galactosamine-mediated drug delivery carrier, galactosamine-conjugated albumin nanoparticles (GAL-AN), was developed for targeted liver cancer therapy. The albumin nanoparticles (AN) and doxorubicin-loaded AN (DOX-AN) were prepared by the desolvation of albumin in the presence of glutaraldehyde crosslinker. Morphological study indicated the spherical structure of these synthesized particles with an average diameter of around 200 nm. The functional ligand of galactosamine (GAL) was introduced onto the surfaces of AN and DOX-AN via carbodiimide chemistry to obtain GAL-AN and GAL-DOX-AN. Cellular uptake and kinetic studies showed that GAL-AN is able to be selectively incorporated into the HepG2 cells rather than AoSMC cells due to the existence of asialoglycoprotein receptors on HepG2 cell surface. The cytotoxicity, measured by MTT test, indicated that AN and GAL-AN are non-toxic and GAL-DOX-AN is more effective in HepG2 cell killing than that of DOX-AN. As such, our results implied that GAL-AN and GAL-DOX-AN have specific interaction with HepG2 cells via the recognition of GAL and asialoglycoprotein receptor, which renders GAL-AN a promising anticancer drug delivery carrier for liver cancer therapy.
Publisher: American Chemical Society (ACS)
Date: 18-07-2006
DOI: 10.1021/LA0606345
Abstract: Well-defined stimuli-responsive mono and dual fullerene (C(60)) end-capped poly(acrylic acid)s (PAA-C(60) and C(60)-PAA-C(60)) were synthesized by reacting C(60) with well-defined mono and dual azide end-functionalized poly(tert-butyl acrylate)s, followed by hydrolysis. The aggregation behaviors of these C(60) end-capped polymers in aqueous solution were examined using potentiometric and conductometric titrations and static and dynamic light scattering as well as transmission electron microscopy (TEM). Both PAA-C(60) and C(60)-PAA-C(60) show pH-responsive and water-soluble properties at high pH. Both polymers self-assemble to form large compound micelles (LCMs) in aqueous solutions. The LCMs of PAA-C(60) exist as "compact aggregates", whereas the LCMs of C(60)-PAA-C(60) possess a "core-shell" structure with a larger size and aggregation number. The micelles for both polymers swell upon neutralization, where the R(h) of PAA-C(60) micelles increases from approximately 44 to approximately 102 nm and the R(h) of C(60)-PAA-C(60) aggregates varies from approximately 89 to approximately 128 nm with increasing degree of neutralization. The lower swelling of the dual end-capped C(60)-PAA-C(60) system is related to its higher C(60) content, which enhances the interpolymer chain hydrophobic association that restrains the swelling of micellar aggregates.
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 2016
Publisher: Elsevier BV
Date: 11-2015
Publisher: American Chemical Society (ACS)
Date: 26-08-2004
DOI: 10.1021/LA048826S
Abstract: A novel pH- and temperature-responsive water-soluble [60]fullerene-containing poly[2-(dimethylamino)ethyl methacrylate] (C60-b-PDMAEMA) was synthesized by atom transfer radical polymerization. The pH and temperature dependence of the physical properties of the aqueous C60-b-PDMAEMA solution was studied by potentiometric and conductometric titrations, UV-vis transmittance, and laser light scattering techniques. At low pH and at temperatures ranging from 25 to 55 degrees C, in addition to C60-b-PDMAEMA unimers, micelle-like aggregates are produced in the aqueous solution containing C60 hydrophobic cores and protonated PDMAEMA shells. Only unimeric C60-b-PDMAEMAs are found to exist in solution at high pH and low temperature, where PDMAEMA segments form a charge-transfer complex with C60 molecules. However, C60-b-PDMAEMA precipitates from aqueous solution at temperatures exceeding the lower critical solution temperature of PDMAEMA of approximately 45 degrees C. The pH and temperature stimuli-responsive properties of the [60]fullerene-containing polymer in aqueous solution are completely reversible.
Publisher: American Chemical Society (ACS)
Date: 15-10-2015
DOI: 10.1021/ACS.LANGMUIR.5B02773
Abstract: Curcumin-encapsulated polyester nanoparticles (Cur-polyester NPs) of approximately 100 nm diameter with a negatively charged surface were prepared using a one-step nanoprecipitation method. The Cur-polyester NPs were prepared using polylactic acid, poly(D,L-lactic-co-glycolic acid) and poly(ϵ-caprolactone) without any emulsifier or surfactant. The encapsulation of curcumin in these polyester NPs greatly suppresses curcumin degradation in the aqueous environment due to its segregation from water. In addition, the fluorescence of curcumin in polyester NPs has a quantum yield of 4 to 5%, which is higher than that of curcumin in micellar systems and comparable to those in organic solvents, further supporting the idea that the polyester NPs are capable of excluding water from curcumin. Furthermore, the results from femtosecond fluorescence upconversion spectroscopy reveal that there is a decrease in the signal litude corresponding to solvent reorganization of excited state curcumin in the polyester NPs compared with curcumin in micellar systems. The Cur-polyester NPs also show a lack of deuterium isotope effect in the fluorescence lifetime. These results indicate that the interaction between curcumin and water in the polyester NPs is significantly weaker than that in micelles. Therefore, the aqueous stability of curcumin is greatly improved due to highly effective segregation from water. The overall outcome suggests that the polyester NPs prepared using the method reported herein are an attractive system for encapsulating and stabilizing curcumin in the aqueous environment.
Publisher: Wiley
Date: 29-11-2014
Publisher: American Chemical Society (ACS)
Date: 30-03-2004
DOI: 10.1021/JP037144V
Publisher: Wiley
Date: 06-10-2014
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 07-2011
Publisher: Wiley
Date: 12-01-2015
Abstract: Poor cellular uptake of drug delivery carriers and uncontrolled drug release remain to be the major obstacles in cancer therapy due to their low delivery efficiency. In this study, a multifunctional intracellular GSH (glutathione)-responsive silica-based drug delivery system with enhanced cellular uptake capability is developed. Uniform 50 nm colloidal mesoporous silica nanoparticles (MSNs) with mercaptopropyl-functionalized core and silanol-contained silica surface (MSNs-SHin ) are designed and fabricated as a platform for drug covalent attachment and particle surface modification. Doxorubicin (DOX) with primary amine group as an anticancer model drug is covalently conjugated to the mesopores of MSNs-SHin via disulfide bonds in the presence of a heterobifunctional linker (N-Succinimidyl 3-(2-pyridyldithio) propionate). Poly(γ-glutamic acid) (γ-PGA) can be coated onto the particle surface by sequential electrostatic adsorption of polyethyleneimine (PEI) and γ-PGA. The constructed delivery system exhibits enhanced cellular uptake via a speculated γ-glutamyl transpeptidase (GGT)-mediated endocytosis pathway and controlled drug release capacity via intracellular GSH-responsive disulfide-bond cleavage, and thus significantly inhibits the growth of cancer cells. The multifunctional delivery system paves a new way for developing high-efficient particle-based nanotherapeutic approach for cancer treatment.
Publisher: American Chemical Society (ACS)
Date: 12-11-2005
DOI: 10.1021/JP053088H
Abstract: A well-defined poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA-b-C60) was synthesized using the atom transfer radical polymerization (ATRP) technique and betainized with 1,3-sulfobetaine to yield a Bet-PDMAEMA-b-C60. The solution properties were then studied by light transmittance, viscometric, 1H NMR laser light scattering, and transmission electron macroscopic techniques. It was found that Bet-PDMAEMA-b-C60 exhibits an upper critical solution temperature (USCT) similar to that observed for Bet-PDMAEMA in aqueous solution. However, the modification of Bet-PDMAEMA with a C60 molecule increases the UCST of Bet-PDMAEMA in solution, which is a function of the solution ionic strength. Addition of a small amount of salt increases the UCST, similar to polyelectrolyte systems, while the presence of an excess amount of salt leads to a decrease in the UCST, attributed to the antipolyelectrolyte effect of poly holytes. In aqueous salt solution, Bet-PDMAEMA-b-C60 chains self-assemble into micelles that coexist with unimeric Bet-PDMAEMA-b-C60 chains. TEM studies revealed that the system agglomerates when the temperature exceeds the UCST.
Publisher: Wiley
Date: 29-12-2017
Publisher: American Chemical Society (ACS)
Date: 02-08-2012
DOI: 10.1021/JP302651X
Publisher: Elsevier BV
Date: 06-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B714741D
Publisher: Elsevier BV
Date: 11-2017
Publisher: Elsevier BV
Date: 02-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 04-07-2014
DOI: 10.1039/C4RA02852J
Publisher: American Chemical Society (ACS)
Date: 27-01-2004
DOI: 10.1021/LA035837X
Publisher: American Chemical Society (ACS)
Date: 31-05-2001
DOI: 10.1021/MA0100807
Publisher: Wiley
Date: 07-04-2022
Abstract: Carbon‐based single‐atom iron electrocatalysts with nitrogen coordination (CSAIN) have recently shown enormous promise to replace the costly Pt for boosting the cathodic oxygen reduction reaction (ORR) in fuel cells. However, there remains a great challenge to achieve highly efficient CSAIN catalysts for the ORR in acidic electrolytes. Herein, a novel CSAIN catalyst is synthesized by pyrolyzing a precursor mixture consisting of metal–organic framework and conductive polymer hybrid. After pyrolysis at a high temperature, the CSAIN with a structure of carbon nanosheet supported polyhedral carbon is achieved, where the unique structure endows CSAIN with expediting electron transfer and mass transport, as well as largely exposed surface to host atomically dispersed iron active sites. As a result, the optimal CSAIN catalyst shows a high ORR activity with its half‐wave potential of 0.77 V (vs RHE) and a Tafel slope of 74.1 mV dec –1 , which are comparable to that of commercial Pt/C catalyst (0.80 V and 81.9 mV dec –1 ).
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.ENZMICTEC.2014.09.010
Abstract: Immobilization of the enzymes on nano-structured materials is a promising approach to enhance enzyme stabilization, activation and reusability. This study aimed to develop polystyrene fiber-enzyme assembles to catalyze model formaldehyde to methanol dehydrogenation reaction, which is an essential step for bioconversion of CO2 to a renewable bioenergy. We fabricated and modified electrospun polystyrene fibers, which showed high capability to immobilize dehydrogenase for the fiber-enzyme assembles. Results from evaluation of biochemical activities of the fiber-enzyme assemble showed that nitriation with the nitric/sulfuric acid ratio (v/v, 10:1) and silanization treatment delivered desirable enzyme activity and long-term storage stability, showing great promising toward future large-scale applications.
Publisher: Wiley
Date: 04-03-2014
Abstract: Ultrathin graphitic carbon nitride (g-C3N4) nanosheets, due to their interesting two-dimensional graphene-like structure and unique physicochemical properties, have attracted great research attention recently. Here, a new approach is developed to prepare, for the first time, proton-functionalized ultrathin g-C3N4 nanosheets by sonication-exfoliation of bulk g-C3N4 under an acid condition. This method not only reduces the exfoliation time from more than 10 h to 2 h, but also endows the nanosheets with positive charges. Besides retaining the properties of g-C3N4, the obtained nanosheets with the thickness of 2-4 nm (i.e., 6-12 atomic monolayers) also exhibit large specific surface area of 305 m(2) g(-1), enhanced fluorescence intensity, and excellent water dispersion stability due to their surface protonation and ultrathin morphology. The well-dispersed protonated g-C3N4 nanosheets are able to interact with negatively charged heparin, which results in the quenching of g-C3N4 fluorescence. A highly sensitive and highly selective heparin sensing platform based on protonated g-C3N4 nanosheets is established. This metal-free and fluorophore label-free system can reach the lowest heparin detection limit of 18 ng mL(-1).
Publisher: American Chemical Society (ACS)
Date: 10-2001
DOI: 10.1021/JP010672R
Publisher: American Chemical Society (ACS)
Date: 30-09-2004
DOI: 10.1021/LA049747J
Publisher: American Chemical Society (ACS)
Date: 07-04-2016
Abstract: Thermoresponsive microgels with carboxylic acid functionalization have been recently introduced as an attractive draw agent for forward osmosis (FO) desalination, where the microgels showed promising water flux and water recovery performance. In this study, various comonomers containing different carboxylic acid and sulfonic acid functional groups were copolymerized with N-isopropylacrylamide (NP) to yield a series of functionalized thermoresponsive microgels possessing different acidic groups and hydrophobicities. The purified microgels were examined as the draw agents for FO application, and the results show the response of water flux and water recovery was significantly affected by various acidic comonomers. The thermoresponsive microgel with itaconic acid shows the best overall performance with an initial water flux of 44.8 LMH, water recovery up to 47.2% and apparent water flux of 3.1 LMH. This study shows that the incorporation of hydrophilic dicarboxylic acid functional groups into the microgels leads to the enhancement on water adsorption and overall performance. Our work elucidates in detail on the structure-property relationship of thermoresponsive microgels in their applications as FO draw agents and would be beneficial for future design and development of high performance FO desalination.
Publisher: Elsevier BV
Date: 04-2020
Publisher: American Chemical Society (ACS)
Date: 10-2019
Publisher: Wiley
Date: 04-10-2016
Publisher: Wiley
Date: 08-02-2018
Publisher: American Chemical Society (ACS)
Date: 26-08-2000
DOI: 10.1021/MA000528O
Publisher: Elsevier BV
Date: 07-2014
Publisher: American Chemical Society (ACS)
Date: 18-03-2008
DOI: 10.1021/JP711319A
Publisher: Elsevier BV
Date: 11-2013
Publisher: American Chemical Society (ACS)
Date: 22-06-2009
DOI: 10.1021/BM900444R
Abstract: An interfacial free radical polymerization method was developed to fabricate polysaccharide nanocapsules, in which poor water-soluble drug of felodipine could be effectively encapsulated with good stability during storage. Exemplified by the preparation of felodipine-loaded N-maleoylchitosan (NMCS) nanocapsules, a felodipine/chloroform mixture was dispersed in NMCS aqueous solution with the aid of a nonionic surface active agent. After charging initiator, the vinylated groups of NMCS were polymerized on the oil-water interface. As a result, felodipine was loaded into NMCS nanocapsule. The morphology and the size distribution of synthesized nanocapsules were characterized by field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS) techniques. The quantitative drug loading and sustained release behavior were investigated. The encapsulation efficiency and drug loading content were found to be strongly dependent on the feed felodipine concentration. The release dynamics showed strong correlation with the degree of maleoyl substitution and the feed NMCS concentration during the course of nanocapsules preparation.
Publisher: Elsevier BV
Date: 12-2005
DOI: 10.1016/J.JCIS.2005.05.079
Abstract: The aqueous solution of poly(ethylene oxide) (PEO) in the presence of different concentrations of sodium dodecyl sulfate (SDS) was examined by laser light scattering and isothermal titration calorimetric techniques. A small fraction of PEO aggregates were found to coexist with unimeric PEO chains in dilute solution. The presence of monovalent salt does not alter the hydrodynamic properties of PEO in aqueous solution. Addition of a monovalent anionic surfactant, such as SDS, induces cooperative binding of surfactant monomers to PEO backbones at SDS concentrations ranging from 4.0 mM (critical aggregation concentration) to 16.5 mM (saturation concentration). The hydrodynamic radius of PEO unimers decreases initially and then increases with SDS concentration, resulting from the structural reorganization of the PEO/SDS complex. Beyond the saturation concentration, the hydrodynamic radii of PEO/SDS complex are independent of SDS concentration.
Publisher: Wiley
Date: 09-08-2016
DOI: 10.1002/BIT.26061
Abstract: Mimicking the zonal organization of native articular cartilage, which is essential for proper tissue functions, has remained a challenge. In this study, a thermoresponsive copolymer of chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAAm) was synthesized as a carrier of mesenchymal stem cells (MSCs) to provide a support for their proliferation and differentiation. Microengineered three-dimensional (3D) cell-laden CS-g-PNIPAAm hydrogels with different microstripe widths were fabricated to control cellular alignment and elongation in order to mimic the superficial zone of natural cartilage. Biochemical assays showed six- and sevenfold increment in secretion of glycosaminoglycans (GAGs) and total collagen from MSCs encapsulated within the synthesized hydrogel after 28 days incubation in chondrogenic medium. Chondrogenic differentiation was also verified qualitatively by histological and immunohistochemical assessments. It was found that 75 ± 6% of cells encapsulated within 50 μm wide microstripes were aligned with an aspect ratio of 2.07 ± 0.16 at day 5, which was more organized than those observed in unpatterned constructs (12 ± 7% alignment and a shape index of 1.20 ± 0.07). The microengineered constructs mimicked the cell shape and organization in the superficial zone of cartilage whiles the unpatterned one resembled the middle zone. Our results suggest that microfabrication of 3D cell-laden thermosensitive hydrogels is a promising platform for creating biomimetic structures leading to more successful multi-zonal cartilage tissue engineering. Biotechnol. Bioeng. 2017 : 217-231. © 2016 Wiley Periodicals, Inc.
Publisher: Springer Science and Business Media LLC
Date: 07-2009
Abstract: The stable superparamagnetic colloidal suspension of chitosan-poly(acrylic acid) (CS-PAA)/Fe 3 O 4 nanoparticles was synthesized by graft copolymerization AA on the surface of CS stabilized Fe 3 O 4 nanoparticles. The size, size distribution, structure, and magnetic properties of the resultant CS-PAA/Fe 3 O 4 nanoparticles were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), dynamic light scattering, Fourier transform infrared spectroscopy, x-ray diffraction, and vibrating s le magnetometry (VSM). FE-SEM and TEM showed the spherelike morphology of CS-PAA/Fe 3 O 4 nanoparticles with their diameter ranging from 15 to 60 nm. VSM measurements indicated that CS-PAA/Fe 3 O 4 nanoparticles preserved the superparamagnetism. CS-PAA complex was proved to be a good stabilizer to prepare the well-dispersed suspension of superparamagnetic Fe 3 O 4 nanoparticles. The stabilizing mechanisms were attributed to the electrostatic repulsion and steric hindrance. The controlled release of entrapped c tothecin from these magnetic nanoparticles was studied and the release mechanism was analyzed.
Publisher: Wiley
Date: 26-06-2014
Abstract: Gene therapy presents a unique opportunity for the treatment of genetic diseases, but the lack of multifunctional delivery systems has hindered its clinical applications. Here, a new delivery vector, autofluorescent polyethyleneimine (PEI) nanogels, for highly efficient and traceable gene delivery is developed. Different from commercial high-molecular-weight PEI, the cationic nanogels are noncytotoxic and able to be fragmented due to their unique intracellular microenvironment-responsive structures. The biodegradable nanogels can effectively load plasmid DNA (pDNA), and the self-assembled polyplexes can be cleaved after cellular uptake to improve gene transfection efficiency. Most importantly, the nanogels and the nanogel DNA polyplexes are autofluorescent. The fluorescence is stable in blood plasma and responsive to the intracellular microenvironment. The breakup of the nanogels or polyplexes leads to the loss of fluorescence, and thus the gene delivery and carrier biodegradation processes can be monitored. The reported multifunctional system demonstrates excellent biocompatibility, high transfection efficiency, responsive biodegradability, controlled gene release, label-free and simultaneous fluorescence tracking, which will provide a new platform for future scientific investigation and practical implications in gene therapy.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.COLSURFB.2009.10.040
Abstract: N-maleoylchitosan (NMCS) is a biocompatible derivative of chitosan, but its solubility in water is dependent on the degree of maleoyl substitution. In this study, the NMCS s le with a maleoyl substitution degree of 70% was synthesized by the reaction of maleic anhydride and the amino groups of chitosan. The resulting NMCS can be ready to dissolve in water over a wide pH range (from 2 to 9). The aggregation behavior of NMCS in aqueous media was studied by steady-state fluorescence spectroscopy, viscometric, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The critical aggregation concentration (CAC) of NMCS in water is found to be 0.05-0.06mg/mL. With increasing NMCS concentration to approximately 0.5mg/mL, which is 10 times of the CAC, NMCS molecules self-assemble to fiber-like aggregates with an averaged diameter of approximately 2.5microm and length of more than 100microm. The driving force for the aggregation is attributed to the hydrophobic interaction as evident from isothermal titration calorimetry (ITC) study. These fiber-like aggregates might have potential applications in tissue engineering scaffold.
Publisher: Wiley
Date: 30-03-2011
DOI: 10.1002/APP.33925
Publisher: American Chemical Society (ACS)
Date: 09-07-2003
DOI: 10.1021/MA025728+
Publisher: Elsevier BV
Date: 09-2018
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.ACTBIO.2008.10.022
Abstract: Fe(3)O(4) nanoparticles were stabilized using different functional polysaccharides, such as chitosan (CS), O-carboxymethylchitosan (OCMCS) and (N-succinyl-O-carboxymethylchitosan (NSOCMCS) to improve their bioactivity. The release profile and the in vitro cancer cell inhibition activity of c tothecin (CPT) loaded polysaccharide modified Fe(3)O(4) nanoparticles were systematically studies. The particle size and size distribution of CPT-loaded polysaccharide modified Fe(3)O(4) nanoparticles were found to be strongly dependent on polysaccharide character. Such polysaccharide character could also affect CPT adsorption efficiency, CPT release behavior and bovine serum albumin (BSA) unspecific binding capacity. After 24 h incubation of 7721 cancer cells with CPT-loaded polysaccharide modified Fe(3)O(4) nanoparticles, significant changes in cell morphology could be discernible from phase contrast microscopy. Cytotoxicity assay showed these polysaccharide modified Fe(3)O(4) nanoparticles did not exhibit noteworthy cytotoxicity against 7721, however, the in vitro inhibition rate of CPT-loaded polysaccharide modified Fe(3)O(4) nanoparticles against 7721 liver cancer cell increased significantly in comparison with that of CPT-free drug.
Publisher: Wiley
Date: 10-2022
Publisher: Wiley
Date: 02-10-2015
Publisher: Elsevier BV
Date: 12-2016
Publisher: American Chemical Society (ACS)
Date: 22-09-2014
DOI: 10.1021/JA5082553
Abstract: Hybrid porous nanowire arrays composed of strongly interacting Co3O4 and carbon were prepared by a facile carbonization of the metal-organic framework grown on Cu foil. The resulting material, possessing a high surface area of 251 m(2) g(-1) and a large carbon content of 52.1 wt %, can be directly used as the working electrode for oxygen evolution reaction without employing extra substrates or binders. This novel oxygen evolution electrode can smoothly operate in alkaline solutions (e.g., 0.1 and 1.0 M KOH), affording a low onset potential of 1.47 V (vs reversible hydrogen electrode) and a stable current density of 10.0 mA cm(-2) at 1.52 V in 0.1 M KOH solution for at least 30 h, associated with a high Faradaic efficiency of 99.3%. The achieved ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the state-of-the-art noble-metal/transition-metal and nonmetal catalysts, originate from the unique nanowire array electrode configuration and in situ carbon incorporation, which lead to the large active surface area, enhanced mass/charge transport capability, easy release of oxygen gas bubbles, and strong structural stability. Furthermore, the hybrid Co3O4-carbon porous nanowire arrays can also efficiently catalyze oxygen reduction reaction, featuring a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices.
Publisher: Elsevier BV
Date: 10-2016
Publisher: Wiley
Date: 12-05-2015
Publisher: Wiley
Date: 24-07-2018
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4968084
Publisher: American Chemical Society (ACS)
Date: 02-07-2005
DOI: 10.1021/LA050651E
Abstract: At low pH conditions and in the presence of anionic, cationic, and nonionic surfactants, hydrophobically modified alkali-soluble emulsions (HASE) exhibit pronounced interaction that results in the solubilization of the latex. The interaction between HASE latex and surfactant was studied using various techniques, such as light transmittance, isothermal titration calorimetry, laser light scattering, and electrophoresis. For anionic surfactant, noncooperative hydrophobic binding dominates the interaction at concentrations lower than the critical aggregation concentration (CAC) (C or = CAC), where the cloudy solution becomes clear. For cross-linked HASE latex, anionic surfactant binds only noncooperatively to the latex and causes it to swell. For cationic surfactant, electrostatic interaction occurs at very low surfactant concentrations, resulting in phase separation. With further increase in surfactant concentration, noncooperative hydrophobic and cooperative hydrophobic interactions dominate the binding at low and high surfactant concentrations, respectively. For anionic and cationic surfactant systems, the CAC is lower than the critical micelle concentration (CMC) of surfactants in water. In addition, counterion condensation plays an important role during the binding interaction between HASE latex and ionic surfactants. In the case of nonionic surfactants, free surfactant micelles are formed in solution due to their relatively low CMC values, and HASE latexes are directly solubilized into the micellar core of nonionic surfactants.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: Start date not available
End Date: 2016
Funder: Australian Research Council
View Funded ActivityStart Date: 2011
End Date: 2016
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2016
Funder: Australian Research Council
View Funded Activity