ORCID Profile
0000-0002-9097-0179
Current Organisations
Macquarie University
,
The University of Dodoma
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Nanomedicine | Other Physical Sciences | Biomedical Instrumentation | Optical Properties of Materials | Medicinal and Biomolecular Chemistry | Nanotechnology | Nanochemistry and Supramolecular Chemistry | Biologically Active Molecules | Synchrotrons; Accelerators; Instruments and Techniques | Medical Biochemistry: Proteins and Peptides (incl. Medical Proteomics) | Bioprocessing, Bioproduction and Bioproducts | Analytical Biochemistry |
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in the Biological Sciences | Service Industries Standards and Calibrations | Nutraceuticals and Functional foods | Expanding Knowledge in the Medical and Health Sciences | Expanding Knowledge in Technology
Publisher: MDPI AG
Date: 29-09-2021
DOI: 10.3390/NANO11102565
Abstract: Gold nanoparticles have the potential to be used in biomedical applications from diagnostics to drug delivery. However, interactions of gold nanoparticles with different biomolecules in the cellular environment result in the formation of a “protein corona”—a layer of protein formed around a nanoparticle, which induces changes in the properties of nanoparticles. In this work we developed methods to reproducibly synthesize spheroidal and star-shaped gold nanoparticles, and carried out a physico-chemical characterization of synthesized anionic gold nanospheroids and gold nanostars through transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential (ZP), nanoparticles tracking analysis (NTA), ultraviolet-visible (UV–Vis) spectroscopy and estimates of surface-enhanced Raman spectroscopy (SERS) signal enhancement ability. We analyzed how they interact with proteins after pre-incubation with bovine serum albumin (BSA) via UV–Vis, DLS, ZP, NTA, SERS, cryogenic TEM (cryo-TEM) and circular dichroism (CD) spectroscopy. The tests demonstrated that the protein adsorption on the particles’ surfaces was different for spheroidal and star shaped particles. In our experiments, star shaped particles limited the protein corona formation at SERS “hot spots”. This benefits the small-molecule sensing of nanostars in biological media. This work adds more understanding about protein corona formation on gold nanoparticles of different shapes in biological media, and therefore guides design of particles for studies in vitro and in vivo.
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B704881E
Publisher: American Chemical Society (ACS)
Date: 16-08-2007
DOI: 10.1021/LA700899S
Abstract: The purpose of this work is to study the kinetics of self-assembly in the formation mechanism of anionic templated mesoporous solids (AMS-n) during the first few seconds of the synthesis as well as to demonstrate the use of alternating ion current (AIC) conductivity measurements to follow the self-assembly in complex hybrid systems. The formation of different AMS-n caged-type mesostructures through the delayed addition of the silica source is demonstrated and explained in terms of the interaction between the co-structure-directing agent (CSDA) and the oppositely charged surfactant headgroup regions. Our findings, supported by transmission electron microscopy, 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, dynamic light scattering (DLS) measurements, and powder X-ray diffraction suggest that the interaction of the CSDA with the surfactant headgroup occurs within seconds after its addition to the synthesis gel leading to interaction between the polymerizing CSDAs and the oppositely charged micelle and to an increase in the micelle-CSDA aggregate size. Both DLS and AIC measurements agree that this process occurs within the first 1000 s after addition of the CSDA to the synthesis gel at room temperature. In addition to the mechanistic study it was found that the intermediate materials are comprised of a three-layer entity. Time-dependent 29Si MAS NMR studies reveal that an organo-silica layer forms around the micelles prior to a condensed outer inorganic shell of silica.
Publisher: Wiley
Date: 17-04-2012
Abstract: Alum is the most frequently used adjuvant today, primarily inducing Th2 responses. However, Th1-type responses are often desirable within immune therapy, and therefore the development of new adjuvants is greatly needed. Mesoporous silica particles with a highly ordered pore structure have properties that make them very interesting for future controlled drug delivery systems, such as controllable particle and pore size they also have the ability to induce minor immune modulatory effects, as previously demonstrated on human-monocyte-derived dendritic cells (MDDCs). In this study, mesoporous silica particles are shown to be efficiently engulfed by MDDCs within 2 h, probably by phagocytic uptake, as seen by confocal microscopy and transmission electron microscopy. A co-culture protocol is developed to evaluate the capability of MDDCs to stimulate the development of naïve CD4(+) T cells in different directions. The method, involving ELISpot as a readout system, demonstrates that MDDCs, after exposure to mesoporous silica particles (AMS-6 and SBA-15), are capable of tuning autologous naïve T cells into different effector cells. Depending on the size and functionalization of the particles added to the cells, different cytokine patterns are detected. This suggests that mesoporous silica particles can be used as delivery vehicles with tunable adjuvant properties, which may be of importance for several medical applications, such as immune therapy and vaccination.
Publisher: Elsevier BV
Date: 09-2014
Publisher: American Chemical Society (ACS)
Date: 13-03-2021
Publisher: Elsevier BV
Date: 04-2005
Publisher: Research Square Platform LLC
Date: 21-06-2023
DOI: 10.21203/RS.3.RS-3081562/V1
Abstract: Purpose The impact of digital transformation in agriculture, including innovations in crop supply chains, is global. Despite that, the level of this technology practice varies across countries, regions, crop types, technologies, socio-economic statuses, and cultures. In the literature, there needs to be more evidence for digital technologies’ role in the role of equity, ersity, and inclusion (EDI) to improve agricultural supply chains (ASC). Thus, this scoping study synthesizes extant research on the extent to which Emerging Digital Technologies (EDTs) promote EDI in the ASC. Methodology: A scoping approach to systematic literature review (SLR) was applied to achieve the objective by deploying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. The methodology guided the process of conducting the scoping review step by step. Findings: Emerging technologies have been found to focus much on some parts of the ASC (such as transportation) where there are limited studies in other ASC parts. Most emerging technologies have been employed in the food supply chain where there is limited literature on the cash crops supply chain. Research limitations/implications: The evidence gathered through this study informs innovation policies and prioritizes opportunities for future research and practices in the area. IoT, Blockchain, and Machine Learning are among the technologies worth detailed study for EDI in agricultural supply chain innovations. Each of these provides unique contributions but is subject to further evaluation, re-development, and deployment that considers the local context, nature of innovation, and other dynamics within the ecosystem. Originality/value: This review provides insight into the current body of knowledge on the role of EDTs towards addressing EDI in ASC.
Publisher: MDPI AG
Date: 11-09-2014
DOI: 10.3390/NANO4030813
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.BBRC.2015.09.071
Abstract: While our understanding of the molecular events leading to disease onset and progression have increased exponentially, our capacity to therapeutically intervene in these events with new chemical ersity has clearly fallen short of that pace. In the quest to readdress this situation, the drug discovery sector is slowly but increasingly exploring sources of alternative chemical matter, such as the ones provided by material science and nanotechnology. While new functional nano-sized materials hold great promise for the future, our lack of understanding of the long term safety implications associated with systemic exposure as well as the unclear regulatory path ahead h er their present impact in drug development. Paradoxically, the exploitation of novel, functionally active micron-sized, synthetic, non-absorbable chemical matter, for the treatment or prevention of a number of epidemiologically significant conditions remains clearly underexplored. A combination of pre-existing evidence and future potential indicates that micron-sized mesoporous silica materials could be an untapped source of new drug candidates. These are free from both the dreaded high attrition associated with small molecule drug discovery and the uncertainties of nano-size technologies. This, together with the coming of age of synthetic methodologies to control particle size and shape pore size and geometry surface chemistry, bioconjugation and formulation, open up exciting possibilities to exploit this novel chemistry-biology therapeutic interface.
Publisher: American Chemical Society (ACS)
Date: 02-11-2007
DOI: 10.1021/NL0714785
Abstract: The effects of mesoporous silica nano- (270 nm) and microparticles (2.5 microm) with surface areas above 500 m2/g were evaluated on human monocyte-derived dendritic cells (MDDC). Size- and concentration-dependent effects were seen where the smaller particles and lower concentrations affected MDDC to a minor degree compared to the larger particles and higher concentrations, both in terms of viability, uptake, and immune regulatory markers. Our findings support the further development of mesoporous silica particles in drug and vaccine delivery systems.
Publisher: Wiley
Date: 20-08-2019
Publisher: Wiley
Date: 13-07-2011
Abstract: Helical organosilica materials were synthesized for the first time using a novel binaphthyl-based chiral co-monomer in less than 1 hour. The incorporation of a chiral co-monomer in the wall was shown to influence the curvature of the helical materials. As the amount of the chiral co-monomer was increased, the degree of curvature increased, illustrating the importance of this monomer to the overall morphology.
Publisher: MDPI AG
Date: 09-09-2021
DOI: 10.3390/PHARMACEUTICS13091436
Abstract: Melatonin (MLT) is a pineal hormone involved in the regulation of the sleep/wake cycle. The efficacy of exogenous MLT for the treatment of circadian and sleep disorders is variable due to a strong liver metabolism effect. In this work, MLT is encapsulated in mesoporous silica (AMS-6) with a loading capacity of 28.8 wt%, and the mesopores are blocked using a coating of cellulose acetate phthalate (CAP) at 1:1 and 1:2 AMS-6/MLT:CAP ratios. The release kinetics of MLT from the formulations is studied in simulated gastrointestinal fluids. The permeability of the MLT released from the formulations and its 6-hydroxylation are studied in an in vitro model of the intestinal tract (Caco-2 cells monolayer). The release of MLT from AMS-6/MLT:CAP 1:2 is significantly delayed in acidic environments up to 40 min, while remaining unaffected in neutral environments. The presence of CAP decreases the absorption of melatonin and increases its catabolism into 6-hydroxylation by the cytochrome P450 enzyme CYP1A2. The simple confinement of melatonin into AMS-6 pores slightly affects the permeability and significantly decreases melatonin 6-hydroxylation. Measurable amounts of silicon in the basolateral side of the Caco-2 cell monolayer might suggest the dissolution of AMS-6 during the experiment.
Publisher: Wiley
Date: 05-12-2011
Publisher: MDPI AG
Date: 28-02-2023
DOI: 10.3390/PHARMACEUTICS15030798
Abstract: There is potential for cannabidiol to act as an analgesic, anxiolytic and antipsychotic active ingredient however, there is a need to find alternate administration routes to overcome its low oral bioavailability. In this work, we propose a new delivery vehicle based on encapsulation of cannabidiol within organosilica particles as drug delivery vehicles, which are subsequently incorporated within polyvinyl alcohol films. We investigated the long-term stability of the encapsulated cannabidiol, as well as its release rate, in a range of simulated fluids with different characterization techniques, including Fourier Transform Infrared (FT-IR) and High-performance Liquid Chromatography (HPLC). Finally, we determined the transdermal penetration in an ex vivo skin model. Our results show that cannabidiol is stable for up to 14 weeks within polyvinyl alcohol films at a range of temperatures and humidity. Release profiles are first-order, consistent with a mechanism involving diffusion of the cannabidiol (CBD) out of the silica matrix. The silica particles do not penetrate beyond the stratum corneum in the skin. However, cannabidiol penetration is enhanced and is detected in the lower epidermis, which was 0.41% of the total CBD in a PVA formulation compared with 0.27% for pure CBD. This is partly due to an improvement of its solubility profile as it is released from the silica particles, but we cannot rule out effects of the polyvinyl alcohol. Our design opens a route for new membrane technologies for cannabidiol and other cannabinoid products, where administration via non-oral or pulmonary routes can lead to better outcomes for patient cohorts in a range of therapeutics.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.ADDR.2009.11.008
Abstract: The development of nanoparticles for biomedical applications including medical imaging and drug delivery is currently undergoing a dramatic expansion. However, as the range of nanoparticle types and applications increases, it is also clear that the potential toxicities of these novel materials and the properties driving such toxic responses must also be understood. Indeed, a detailed assessment of the factors that influence the biocompatibility and/or toxicity of nanoparticles is crucial for the safe and sustainable development of the emerging nanotechnologies. This review summarizes some of the recent developments in the field of nanomedicine with particular emphasis on inorganic nanoparticles for drug delivery. The synthesis routes, physico-chemical characteristics, and cytotoxic properties of inorganic nanoparticles are thus explored and lessons learned from the toxicological investigation of three common types of engineered nanomaterials of titania, gold, and mesoporous silica are discussed. Emphasis is placed on the recognition versus non-recognition of engineered nanomaterials by the immune system, the primary surveillance system against microorganisms and particles, which, in turn, is intimately linked to the issue of targeted drug delivery using such nanomaterials as carrier systems.
Publisher: MDPI AG
Date: 24-02-2022
DOI: 10.3390/PHARMACEUTICS14030502
Abstract: Brain endothelial cells mediate the function and integrity of the blood brain barrier (BBB) by restricting its permeability and exposure to potential toxins. However, these cells are highly susceptible to cellular damage caused by oxidative stress and inflammation. Consequent disruption to the integrity of the BBB can lead to the pathogenesis of neurodegenerative diseases. Drug compounds with antioxidant and/or anti-inflammatory properties therefore have the potential to preserve the structure and function of the BBB. In this work, we demonstrate the enhanced antioxidative effects of the compound probucol when loaded within mesoporous silica particles (MSP) in vitro and in vivo zebrafish models. The dissolution kinetics were significantly enhanced when released from MSPs. An increased reduction in lipopolysaccharide (LPS)-induced reactive oxygen species (ROS), cyclooxygenase (COX) enzyme activity and prostaglandin E2 production was measured in human brain endothelial cells treated with probucol-loaded MSPs. Furthermore, the LPS-induced permeability across an endothelial cell monolayer by paracellular and transcytotic mechanisms was also reduced at lower concentrations compared to the antioxidant ascorbic acid. Zebrafish pre-treated with probucol-loaded MSPs reduced hydrogen peroxide-induced ROS to control levels after 24-h incubation, at significantly lower concentrations than ascorbic acid. We provide compelling evidence that the encapsulation of antioxidant and anti-inflammatory compounds within MSPs can enhance their release, enhance their antioxidant effects properties, and open new avenues for the accelerated suppression of neuroinflammation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0BM00445F
Abstract: Mesoporous silica particles (MSPs) enhance and allow to control the release kinetics of poorly soluble compound probucol (PB) under the influence of a pore-blocking lysozyme protein corona.
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.EJPS.2019.105038
Abstract: Antioxidants play a vital role in scavenging reactive oxygen species (ROS) produced by the reduction of molecular oxygen from various cellular mechanisms. Under oxidative stress, an increase in the levels of ROS overwhelms the antioxidant response, causing oxidative damage to biological molecules, and leading to the development of various diseases. Drug compounds with potent antioxidant properties are typically poorly water soluble and highly hydrophobic. An extreme case is Probucol (PB), a potent antioxidant with reported water solubility of 5 ng/ml, and oral bioavailiability of <10%. In this study, PB was loaded in mesoporous silica at various drug loadings to understand the changes to the physical properties of the loaded drug, and it's in vitro drug release. Further in vitro studies were conducted in endothelial and microglia cell models to compare the free radical scavening efficiency of ascorbic acid, PB, and PB release from mesoporous silica particles. Out of the three different mesostructured particles studied, the maximum loading of PB was achieved for large pore mesoporous particles (SBA-15) at 50 wt% drug loading, before complete pore filling was observed. For all materials, loadings above complete pore filling resulted in the recrystallization of PB on the external surface. In vitro drug release measurements showed a rapid dissolution rate at low drug loadings compared to a bimodal release profile of amorphous and crystalline drug at higher drug loadings. PB loaded in mesoporous particle was shown to enhance the antioxidant response to extracellular ROS in the endothelial cell line model, and to intracellular ROS in the microglia cell model. Our results indicate that the antioxidant properties of PB can be significantly improved by using mesoporous silica as a delivery vehicle.
Publisher: WORLD SCIENTIFIC
Date: 29-09-2014
Publisher: Wiley
Date: 24-03-2006
Publisher: Bentham Science Publishers Ltd.
Date: 07-2008
DOI: 10.2174/156720108784911686
Abstract: We present here a detailed study of the controlled release of amino acid derived hiphilic molecules from the internal pore structure of mesoporous nanoparticle drug delivery systems with different structural properties namely cubic and hexagonal structures of various degrees of complexity. The internal pore surface of the nanomaterials presented has been functionalised with amine moieties through a one pot method. Release profiles obtained by Alternating Ionic Current measurements are interpreted in terms of specific structural and textural parameters of the porous nanoparticles such as pore geometry and connectivity. Results indicate that diffusion coefficients are lower by as much as four orders of magnitude in 2-dimensional structures in comparison to 3-dimensional mesoporous solids. A fast release in turn is observed from mesocaged materials AMS-9 and AMS-8 where the presence of structural defects is thought to lead to a slightly lower diffusion coefficient in the latter. Amount of pore wall functionalisation and number of binding sites on the model drug are found to have little effect on the drug release rate.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TB00445A
Abstract: The protein corona of nanodiamonds is dominated by low molecular weight proteins and is largely independent of surface chemistry. The pre-incubation of nanodiamonds in serum and the formation of a protein corona decrease the production of reactive oxygen species, increasing the cell viability of macrophages.
Publisher: American Chemical Society (ACS)
Date: 12-03-2009
DOI: 10.1021/LA900105U
Abstract: A new method to investigate the effect of pore geometry on diffusion processes in mesoporous silica nanoparticles and other types of micro- and mesoporous structures is put forward. The method is based on the study of proton diffusion from a liquid surrounding the mesoporous particles into the particle pore system. The proton diffusion properties are assessed for a variety of as-synthesized mesoporous nano- and microparticles with two-dimensional and three-dimensional connectivity. Results show that the diffusion coefficients are higher for the proton absorption process than for the release of surfactant template molecules, and that they overall follow the same trend with the more complex three-dimensional mesocaged particles showing the highest diffusion coefficients. The pore geometry (cylindrical pores versus cage-type pores) and structure connectivity are found to play a key role for the effects observed. The results put forward in the present work should offer a valuable tool in the development of porous nanomaterials in a range of applications including the use as catalysis and separation enhancers in the petrochemical industry, as scaffolds for hydrogen storage, and as drug delivery vehicles for sustained release and gene transfection.
Publisher: Elsevier BV
Date: 06-2021
Publisher: American Chemical Society (ACS)
Date: 06-09-2008
DOI: 10.1021/JP805123W
Abstract: We present a novel conducting polypyrrole-based composite material, obtained by polymerization of pyrrole in the presence of iron(III) chloride on a cellulose substrate derived from the environmentally polluting Cladophora sp. algae. The material, which was doped with chloride ions, was molded into paper sheets and characterized using scanning and transmission electron microscopy, N 2 gas adsorption analysis, cyclic voltammetry, chrono erometry and conductivity measurements at varying relative humidities. The specific surface area of the composite was found to be 57 m (2)/g and the fibrous structure of the Cladophora cellulose remained intact even after a 50 nm thick layer of polypyrrole had been coated on the cellulose fibers. The composite could be repeatedly used for electrochemically controlled extraction and desorption of chloride and an ion exchanging capacity of 370 C per g of composite was obtained as a result of the high surface area of the cellulose substrate. The influence of the oxidation and reduction potentials on the chloride ion exchange capacity and the nucleation of delocalized positive charges, forming conductive paths in the polypyrrole film, was also investigated. The creation of conductive paths during oxidation followed an effective medium rather than a percolative behavior, indicating that some conduction paths survive the polymer reduction steps. The present high surface area material should be well-suited for use in, e.g., electrochemically controlled ion exchange or separation devices, as well as sensors based on the fact that the material is compact, light, mechanically stable, and moldable into paper sheets.
Publisher: American Chemical Society (ACS)
Date: 09-08-2011
DOI: 10.1021/LA202033P
Publisher: American Chemical Society (ACS)
Date: 11-09-2013
DOI: 10.1021/LA401532J
Abstract: A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, and in situ conductivity measurements are used to investigate the organic-inorganic interactions and synthesis mechanism. The behavior of folate molecules in solution differs distinctively from that of surfactants commonly used for the preparation of ordered mesoporous silica phases, notably with the absence of a critical micellar concentration. In situ SAXS studies reveal fluctuations in X-ray scattering intensities consistent with the condensation of the silica precursor surrounding the folate template and the growth of the silica mesostructure in the initial stages. High-angle X-ray diffraction shows that the folate template is well-ordered within the pores even after a few minutes of synthesis. Direct structural data for the self-assembly of folates into chiral tetramers within the pores of mesoporous silica provide evidence for the in register stacking of folate tetramers, resulting in a chiral surface of rotated tetramers, with a rotation angle of 30°. Additionally, the self-assembled folates within pores were capable of adsorbing a considerable amount of CO2 gas through the cavity space of the tetramers. The study demonstrates the validity of using a naturally occurring template to produce relevant and functional mesoporous materials.
Publisher: American Chemical Society (ACS)
Date: 10-03-2010
DOI: 10.1021/LA1001495
Abstract: Adsorption-mediated CO(2) separation can reduce the cost of carbon capture and storage. The reduction in cost requires adsorbents with high capacities for CO(2) sorption and high CO(2)-over-N(2) selectivity. Amine-modified sorbents are promising candidates for carbon capture. To investigate the details of CO(2) adsorption in such materials, we studied mesocaged (cubic, Pm3n symmetry) silica adsorbents with tethered propylamines using Fourier transform infrared (FTIR) spectroscopy and volumetric uptake experiments. The degree of heterogeneity in these coatings was varied by either cosynthesizing or postsynthetically introducing the propylamine modification. In situ FTIR spectroscopy revealed the presence of both physisorbed and chemisorbed CO(2) in the materials. We present direct molecular evidence for physisorption using FTIR spectroscopy in mesoporous silica sorbents modified with propylamines. Physisorption reduced the CO(2)-over-N(2) selectivity in amine-rich sorbents. S les with homogeneous coatings showed typical CO(2) adsorption trends and large quantities of IR-observable physisorbed CO(2). The uptake of CO(2) in mesocaged materials with heterogeneous propylamine coatings was higher at high temperatures than at low temperatures. At higher temperatures and low pressures, the postsynthetically modified materials adsorbed more CO(2) than did the extracted ones, even though the surface area after modification was clearly reduced and the coverage of primary amine groups was lower. The principal mode of CO(2) uptake in postsynthetically modified mesoporous silica was chemisorption. The chemisorbed moieties were present mainly as carbamate-ammonium ion pairs, resulting from the quantitative transformation of primary amine groups during CO(2) adsorption as established by NIR spectroscopy. The heterogeneity in the coatings promoted the formation of these ion pairs. The average propylamine-propylamine distance must be small to allow the formation of carbamate-propylammonium ion pairs.
Publisher: Wiley
Date: 15-08-2005
Publisher: Springer New York
Date: 2014
Publisher: American Chemical Society (ACS)
Date: 03-12-2019
Publisher: Wiley
Date: 28-06-2019
Abstract: Chiral resolution using non-functionalized mesoporous particles is demonstrated for a variety of enantiomeric pairs. This is achieved through the use of supramolecular templated silica materials prepared with guanosine monophosphate (NGM-1) and folic acid (NFM-1) which enable direct chiral transcription onto the surface of the mesopores after solvent extraction and post calcination of the template. The chiral selectivity and kinetics of the mesoporous materials are measured by circular dichroism (CD) spectroscopy on adsorbed molecules with different affinities for the pore surface. NGM-1 and NFM-1 have opposite enantiomeric selectivity for enantiomeric pairs. These results significantly increase the potential of mesoporous materials for chiral separation and enantiomeric catalysis.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Future Medicine Ltd
Date: 03-2012
DOI: 10.2217/NNM.11.109
Abstract: Background: Mesoporous silica-based particles are of potential interest for the development of novel therapeutic targeted delivery vehicles. Their ability to load and release large quantities of active pharmaceutical products with varying properties, combining controlled and targeted release functions make them unique amongst nanotechnology-based carrier systems. Materials & methods: In this study, nanoporous folic acid-templated materials (NFM-1) were prepared and the synthetic strategies for the control of textural and morphology properties of NFM-1 are described. The potential biocompatibility of NFM-1 particles with different morphology (gyroid shaped, fibers and rod-shaped) was assessed using a panel of human cell lines. Results: The results reveal that NFM-1 morphology has an impact on cell viability such that particles showing higher aspect ratios possess increased cytotoxicity. Conclusion: These studies provide useful information for the development of novel mesoporous materials for biomedical applications, including cell-specific drug delivery. Original submitted: 12 April 2011 Revised submitted: 25 May 2011
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.JCIS.2021.12.161
Abstract: The characterization of the protein corona has become an essential part of understanding the biological properties of nanomaterials. This is also important in the case of mesoporous silica particles intended for use as drug delivery excipients. A combination of scattering, imaging and protein characterization techniques is used here to assess the effect of particle shape and growth of the reversible (soft) and strongly bound (hard) corona of three types mesoporous silica particles with different aspect ratios. Notable differences in the protein composition, surface coverage and particle agglomeration of the protein corona-particle complex point to specific protein adsorption profiles highly dependent on exposed facets and aspect ratio. Spherical particles form relatively homogeneous soft and hard protein coronas (approx.10 nm thick) with higher albumin content. In contrast to rod-shaped and faceted particles, which possess soft coronas weakly bound to the external surface and influenced to a greater extent by the particle morphology. These differences are likely important contributors to observed changes in biological properties, such as cell viability and immunological behaviour, with mesoporous silica particle shape.
Publisher: Future Medicine Ltd
Date: 07-2014
DOI: 10.2217/NNM.13.138
Abstract: Background: There is a need for medical treatments to curb the rising rate of obesity. Weight reduction is correlated with a decrease in associated risk factors and cholesterol levels in humans. Amorphous silica particles have been found to exert a hypocholesterolemic effect in humans, making them popular dietary additives. Aim: To investigate the effect of mesoporous silica, which possess sharp pore size distributions, on: weight loss, cholesterol, triglycerides and glucose blood levels in obese mice. Materials & methods: Mesoporous silicas with differing pore size were mixed in the high-fat diet of obese mice. Results: Animals receiving large pore mesoporous silica with a high-fat diet show a significant reduction in body weight and fat composition, with no observable negative effects. Conclusion: Pore size is an important parameter for reduction of body weight and body fat composition by mesoporous silica, demonstrating promising signs for the treatment of obesity. Original submitted 30 January 2013 Revised submitted 20 June 2013
Publisher: Future Medicine Ltd
Date: 2013
DOI: 10.2217/NNM.12.77
Abstract: Background: Mesoporous silica particles are highly promising nanomaterials for biomedical applications. They can be used to improve bioavailability, solubility and drug stability and to protect drugs from the acidic conditions of the stomach, leading to increased drug effectiveness. Their biocompatibility in vivo has recieved little attention, in particular regarding oral administration. Aim: To study the oral tolerance of micron-sized nanoporous folic acid-templated material-1 (cylindrical, 2D hexagonal pore structure) and nanometer-sized anionic-surfactant-templated mesoporous silica material-6 (cylindrical, 3D cubic pore structure) mesoporous silica particles in Sprague Dawley rats. Materials & methods: A dose stepwise procedure or range finding test was followed by a consequent confirmatory test. The confirmatory test included daily administrations of 2000 and 1200 mg/kg doses for nanoporous folic acid-templated material-1 and anionic-surfactant-templated mesoporous silica material-6, respectively. Results: The maximum tolerated dose for anionic-surfactant-templated mesoporous silica material-6 was not reached. Similar results were observed for nanometer-sized anionic-surfactant-templated mesoporous silica material-1 in most of the animals, although adverse effects were observed in some animals that are most probably due to the administration by oral gavage of the formulated particles. Conclusion: The results are promising for the use of mesoporous silica materials as drug-delivery systems in oral administration. Original submitted 8 February 2012 Revised submitted 30 April 2012 Published online 14 August 2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2002
DOI: 10.1039/B205470C
Publisher: Future Medicine Ltd
Date: 11-2014
DOI: 10.2217/NNM.14.23
Abstract: Aim: Stem cell-derived motor neurons (MNs) are utilized to develop replacement strategies for spinal cord disorders. Differentiation of embryonic stem cells into MN precursors involves factors and their repeated administration. We investigated if delivery of factors loaded into mesoporous nanoparticles could be effective for stem cell differentiation in vitro. Materials & methods: We used a mouse embryonic stem cell line expressing green fluorescent protein under the promoter for the MN-specific gene Hb9 to visualize the level of MN differentiation. The differentiation of stem cells was evaluated by expression of MN-specific transcription factors monitored by quantitative real-time PCR reactions and immunocytochemistry. Results: Mesoporous nanoparticles have strong affiliation to the embryoid bodies, penetrate inside the embryoid bodies and come in contact with differentiating cells. Conclusion: Repeated administration of soluble factors into a culture medium can be avoided due to a sustained release effect using mesoporous silica. Original submitted 28 August 2013 Revised submitted 23 January 2014
Publisher: Future Medicine Ltd
Date: 08-2014
DOI: 10.2217/NNM.13.170
Abstract: Aim: To study the adjuvant effect of mesoporous silica particles and their capability of modifying an already existing allergic Th2-like immune response. Materials & methods: The adjuvant effect of Santa Barbara Amorphous-15 (SBA-15) mesoporous silica particles was studied in an antigen-specific ovalbumin (OVA) system in vitro and in vivo. The capacity of the OVA-loaded SBA-15 particles (SBA-15-OVA) to modify an existing immune response was assessed in a murine allergy model. Results: SBA-15-OVA induced significantly stronger OVA-specific splenocyte proliferation compared with OVA alone. Significantly higher IFN-γ production was observed in ex vivo OVA-stimulated splenocytes from SBA-15-OVA-immunized mice compared with mice injected with only SBA-15 or OVA. Treatment of OVA-sensitized mice with SBA-15-OVA modified the immune response with significantly lower serum levels of OVA-specific IgE and higher IgG levels compared with the alum-OVA-treated group. Conclusion: The results are promising for the continued development of mesoporous silica materials for therapeutic applications. Original submitted 18 January 2013 Revised submitted 30 August 2013
Publisher: Wiley
Date: 20-11-2009
DOI: 10.1002/WNAN.13
Abstract: We present here a study of the controlled release of amino acid‐derived hiphilic molecules from the internal pore structure of mesoporous nanoparticle drug delivery systems with different structural properties, namely cubic and hexagonal structures of various degrees of complexity. The internal pore surface of the nanomaterials presented has been functionalised with amine moieties through a one‐pot method. Release profiles obtained by conductivity measurements are interpreted in terms of specific structural and textural parameters of the porous nanoparticles, such as pore geometry and connectivity. Results indicate that diffusion coefficients are lower by as much 4 orders of magnitude in two‐dimensional structures in comparison to three‐dimensional mesoporous solids. A fast release in turn is observed from mesocaged materials AMS‐9 and AMS‐8, where the presence of structural defects is thought to lead to a slightly lower diffusion coefficient in the latter. We conclude that the use of single or mixed phases of these porous systems can be utilized to provide sustained release over long time periods and expect their use in a variety of formulations. Copyright © 2008 John Wiley & Sons, Inc. This article is categorized under: Therapeutic Approaches and Drug Discovery Nanomedicine for Respiratory Disease
Publisher: International Union of Crystallography (IUCr)
Date: 29-02-2020
Publisher: American Chemical Society (ACS)
Date: 03-03-2022
DOI: 10.1021/ACS.MOLPHARMACEUT.1C00781
Abstract: SBA-15 mesoporous silica (MPS) has been widely used in oral drug delivery however, it has not been utilized for solidifying lipid-based formulations, and the impact of their characteristic intrawall microporosity remains largely unexplored. Here, we derive the impact of the MPS microporosity on the
Publisher: Oxford University Press (OUP)
Date: 02-10-2013
Abstract: Stem cell transplantation holds great hope for the replacement of damaged cells in the nervous system. However, poor long-term survival after transplantation and insufficiently robust differentiation of stem cells into specialized cell types in vivo remain major obstacles for clinical application. Here, we report the development of a novel technological approach for the local delivery of exogenous trophic factor mimetics to transplanted cells using specifically designed silica nanoporous particles. We demonstrated that delivering Cintrofin and Gliafin, established peptide mimetics of the ciliary neurotrophic factor and glial cell line-derived neurotrophic factor, respectively, with these particles enabled not only robust functional differentiation of motor neurons from transplanted embryonic stem cells but also their long-term survival in vivo. We propose that the delivery of growth factors by mesoporous nanoparticles is a potentially versatile and widely applicable strategy for efficient differentiation and functional integration of stem cell derivatives upon transplantation.
Publisher: Wiley
Date: 11-09-2014
Abstract: There is large interest in replicating biological supramolecular structures in inorganic materials that are capable of mimicking biological properties. The use of 5-guanosine monophosphate in the presence of Na(+) and K(+) ions as a supramolecular template for the synthesis of well-ordered mesostructured materials is reported here. Mesostructured particles with the confined template exhibit high structural order at both meso- and atomic scales, with a lower structural symmetry in the columnar mesophase. Although a chiral space group can not be deduced from X-ray diffraction, analysis by electron microscopy and circular dichroism confirms a chiral stacking arrangement along the c-axis. Guanosine monophosphate based mesophases thus illustrate the possibility for specific molecular imprinting of mesoporous materials by genetic material and the potential for higher definition in molecular recognition.
Publisher: American Chemical Society (ACS)
Date: 03-02-2004
DOI: 10.1021/CM035074Z
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.BIOMATERIALS.2016.12.029
Abstract: Mesoporous silica-based particles are promising candidates for biomedical applications. Here, we address the importance of macrophage activation status for internalization of AMS6 (approx. 200 nm in diameter) versus AMS8 (approx. 2 μm) mesoporous silica particles and the role of different phagocytosis receptors for particle uptake. To this end, FITC-conjugated silica particles were used. AMS8 were found to be non-cytotoxic both for M-CSF-stimulated (anti-inflammatory) and GM-CSF-stimulated (pro-inflammatory) macrophages, whereas AMS6 exhibited cytotoxicity towards M-CSF-stimulated, but not GM-CSF-stimulated macrophages this toxicity was, however, mitigated in the presence of serum. AMS8 triggered the secretion of pro-inflammatory cytokines in M-CSF-activated cells. Class A scavenger receptor (SR-A) expression was noted in both M-CSF and GM-CSF-stimulated macrophages, although the expression was higher in the former case, and gene silencing of SR-A resulted in a decreased uptake of AMS6 in the absence of serum. GM-CSF-stimulated macrophages expressed higher levels of the mannose receptor CD206 compared to M-CSF-stimulated cells, and uptake of AMS6, but not AMS8, was reduced following the downregulation of CD206 in GM-CSF-stimulated cells particle uptake was also suppressed by mannan, a competitive ligand. These studies demonstrate that macrophage activation status is an important determinant of particle uptake and provide evidence for a role of different macrophage receptors for cell uptake of silica particles.
Publisher: American Chemical Society (ACS)
Date: 10-02-2009
DOI: 10.1021/LA803727U
Abstract: The synthesis of cubic Pm3n mesocaged solid templated by cetyltrimethyl ammonium bromide (C16TMABr) surfactant by direct cocondensation of (3-aminopropyl)triethoxysilanes (APES) under strong alkaline conditions is reported. The novel route gives direct incorporation of amino functional groups on the porous silica wall, and the structural formation has been followed by means of in situ SAXS studies performed at a synchrotron beam line. Data shows that a molar ratio of C16TMABr/APES = 0.6 favors the formation of 3D cubic mesocaged solid with Pm3n symmetry which transforms to a cylindrical mesoporous phase with p6mm symmetry at higher molar ratios. Further structural evaluation has been performed by means electron crystallography (EC). Reconstructed 3D models based on EC show the presence of spherical cages (A-cages, 45 angstroms) and ellipsoidal cages (B-cages, 48 x 43 angstroms) whereby every cage in the unit cell is connected to 14 nearest cages with a window size of 18 angstroms. Finally, a mechanism is proposed, denoted S+ approximately NoI-, in which penetration of the neutral aminopropyl moiety within the micellar corona is responsible for the formation of the Pm3n phase, accounting for the formation of the hexagonal phase at higher molar ratios and higher temperatures. In comparison to other mesocaged materials with the same symmetry this structure possesses a more open porous network which will help assess its potential in a variety of applications discussed herein.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0MA00188K
Abstract: The hard and soft protein corona of mesoporous silica particles and its integrity is significantly affected by their morphology, with spherical particles offering a homogenous protein coating which results in enhanced cellular uptake.
Publisher: American Scientific Publishers
Date: 11-2010
Abstract: Mesoporous NFM-1 silica with folic acid as template was prepared taking advantage of the supramolecular self-assembly of pterin groups and their abilities to form hexagonal liquid crystal phases. NFM-1 materials with the varied morphologies such as fiber, chiral twisting long-rod, gyroid, and amorphous particles were prepared by varying the amount of the co-structure directing agent, stirring speed and changing pH value of the synthesis. The release kinetics of NFM-1 s les with different morphologies were studied in phosphate buffer with pH = 7.4 in 37 degrees C under stirring. All the release kinetic curves are fitted by the power law and Higuchi equations. The fitting of the power law equation was separately done as for the released amount up to 60% or 100%. The materials show slow, long-term and sustained release of folic acid from mesoporous NFM-1 silica, which establishes a new foundation for the potential application in drug delivery and bioimaging.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2003
DOI: 10.1038/NMAT1022
Publisher: MDPI AG
Date: 29-10-2021
DOI: 10.3390/BIOMEDICINES9111578
Abstract: Colonization of distant organs by tumor cells is a critical step of cancer progression. The initial avascular stage of this process (micrometastasis) remains almost inaccessible to study due to the lack of relevant experimental approaches. Herein, we introduce an in vitro/in vivo model of organ-specific micrometastases of triple-negative breast cancer (TNBC) that is fully implemented in a cost-efficient chick embryo (CE) experimental platform. The model was built as three-dimensional (3D) tissue engineering constructs (TECs) combining human MDA-MB-231 cells and decellularized CE organ-specific scaffolds. TNBC cells colonized CE organ-specific scaffolds in 2–3 weeks, forming tissue-like structures. The feasibility of this methodology for basic cancer research, drug development, and nanomedicine was demonstrated on a model of hepatic micrometastasis of TNBC. We revealed that MDA-MB-231 differentially colonize parenchymal and stromal compartments of the liver-specific extracellular matrix (LS-ECM) and become more resistant to the treatment with molecular doxorubicin (Dox) and Dox-loaded mesoporous silica nanoparticles than in monolayer cultures. When grafted on CE chorioallantoic membrane, LS-ECM-based TECs induced angiogenic switch. These findings may have important implications for the diagnosis and treatment of TNBC. The methodology established here is scalable and adaptable for pharmacological testing and cancer biology research of various metastatic and primary tumors.
Publisher: Wiley
Date: 28-06-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 26-11-2002
DOI: 10.1039/B108259K
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.XPHS.2018.03.029
Abstract: Pharmaceutical compounds with poor solubility are loaded within mesoporous materials to understand the effect of mesoscale confinement on their dissolution behavior. Structural and calorimetric characterization is combined with atomic pair distribution function analysis probing the interactions between the silica surface and the loaded amorphous compound. While different degrees of amorphism are not identifiable from X-ray diffraction data or calorimetric techniques, the atomic pair distribution function analysis can help identify local ordering of the drug molecules. Together with a list of drug descriptors such as crystallization properties, molecular size, and glass transition temperature, the behavior of encapsulated compounds and their release kinetics may be rationalized. Dissolution experiments confirm that different release rates can be achieved with small differences in mesopore design, such as the presence of micropores in Santa Barbara Amorphous-15 and loading amount.
Publisher: MDPI AG
Date: 11-01-2021
DOI: 10.3390/MOLECULES26020338
Abstract: Adsorption kinetic studies are conducted to investigate the potential to use chiral mesoporous materials nanoporous guanosine monophosphate material-1 (NGM-1) and nanoporous folic acid material-1 (NFM-1) for the enantiomeric separation of l- and d-valine. A pseudo-second-order (PSO) kinetic model is applied to test the experimental adsorption equilibrium isotherms, according to both the Langmuir and Freundlich models and the characteristic parameters for each model are determined. The calcined versions of both NGM-1 and NFM-1 fit the Langmuir model with maximum sorption capacities of 0.36 and 0.26 g/g for the preferred adsorption enantiomers, d-valine and l-valine, respectively. Experimental results and the analysis of adsorption models suggest a strong adsorbate–adsorbent interaction, and the formation of a monolayer of tightly packed amino acid on the internal mesopore surface for the preferred enantiomers.
Publisher: Wiley
Date: 28-02-2020
Publisher: Future Medicine Ltd
Date: 07-2011
DOI: 10.2217/NNM.11.82
Abstract: Although ordered mesoporous silica materials have been studied for almost 20 years, their utilization within life science applications is relatively new and unexplored. An increasing number of researchers are transcending their respective fields in order to bridge the knowledge gap between materials chemistry and biotechnology, and to exploit the potential of mesoporous materials. Their intricate porosity with order in the nanoscale translates into high surface areas above 1000 m 2 /g, high selectivity for the encapsulation of biorelevant molecules as well as controlled surface chemistry. Their uses in pharmaceutics to improve drug formulation, drug bioavailability, mitigate drug toxicity and in cellular targeting, through controlled drug delivery strategies, have been shown. The incorporation of a high concentration of fluorescent and nuclear markers within their pores, whilst retaining good diffusion through their porous matrix, has shown them to be ideal candidates for sensing devices, in immunoassays such as flow cytometry and for their use in novel theranostic applications. This article aims to bring to the forefront some of the most important properties of mesoporous materials, which prove advantageous for their use in nanomedical applications and to highlight some of the potential areas into which the field may now emerge.
Publisher: American Chemical Society (ACS)
Date: 05-02-2018
DOI: 10.1021/ACS.LANGMUIR.7B03705
Abstract: A colloidal dispersion of uniform organosilica nanoparticles could be produced via the disassembly of the non-surfactant-templated organosilica powder nanostructured folate material (NFM-1). This unusual reaction pathway was available because the folate and silica-containing moieties in NFM-1 are held together by noncovalent interactions. No precipitation was observed from the colloidal dispersion after a week, though particle growth occurred at a solvent-dependent rate that could be described by the Lifshitz-Slyozov-Wagner equation. An organosilica film that was prepared from the colloidal dispersion adsorbed folate-binding protein from solution but adsorbed ions from a phosphate-buffered saline solution to a larger degree. To our knowledge, this is the first instance of a colloidal dispersion of organosilica nanoparticles being derived from a macroscopic material rather than from molecular precursors.
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.FOODCHEM.2016.08.027
Abstract: The ability of a number of mesoporous silica materials (SBA-15, SBA-3, and MCM-48) to immobilize polyphenol oxidase (PPO) at different pH has been tested. Pore size and volume are the structural characteristics with higher influence on the PPO immobilization. Mesoropous material SBA-15 adsorbs a larger quantity of PPO at pH 4.00 and offers an inhibition of enzymatic activity close the 50% in apple extracts.
Publisher: Wiley
Date: 29-11-2010
Abstract: The pressure-swing adsorption method for carbon dioxide capture would ideally be facilitated by adsorbents with a high capacity and a high selectivity for CO₂. Several aluminophosphates with 8-ring window apertures (AlPO₄-17, AlPO₄-18, AlPO₄-53, and AlPO₄-25) were synthesized by hydrothermal crystallization, calcined, and their CO₂ uptake and CO₂/N₂ selectivity were studied. CO₂ and N₂ uptake was determined for pressures up to 101 kPa at 273 and 293 K. Langmuir and Toth adsorption models were used to describe the adsorption isotherms. The CO₂ and N₂ uptakes strongly indicated that the squeezed 8-ring windows of certain aluminophosphates can sieve CO₂ from a CO₂ and N₂ gas mixture. Both AlPO₄-53 and AlPO₄-25 exhibited a remarkably higher uptake of CO₂ compared to N₂. The hydrophilicity of the AlPO₄ materials was investigated by means of water adsorption, and the results showed that all of the tested aluminophosphates were less water sensitive than a benchmark zeolite (13X). In particular, AlPO₄-53 and AlPO₄-25 showed a very low degree of water uptake with up to 20-30 % relative humidity. Determination of cyclic adsorption and desorption confirmed the relatively hydrophobic nature of the aluminophosphates, which render them less energy costly for the regeneration of adsorbents.
Publisher: MDPI AG
Date: 06-09-2021
DOI: 10.20944/PREPRINTS202109.0085.V1
Abstract: Colonization of distant organs by tumor cells is a critical step of cancer progression. The initial avascular stage of this process (micrometastasis) remains almost inaccessible to study due to the lack of relevant experimental approaches. Here, we introduce an in vitro/in vivo model of organ-specific micrometastases of triple-negative breast cancer (TNBC) that is fully implemented in a cost-efficient chick embryo (CE) experimental platform. The model is built as three-dimensional (3D) tissue engineering constructs (TECs) combining human MDA-MB-231 cells and decellular-ized CE organ-specific scaffolds. TNBC cells colonized CE organ-specific scaffolds in 2-3 weeks, forming tissue-like structures. The feasibility of this methodology for basic cancer research, drug development and nanomedicine was demonstrated on a model of hepatic micrometastasis of TNBC. We revealed that MDA-MB-231 differentially colonize parenchymal and stromal com-partments of the liver-specific extracellular matrix (LS-ECM) and become more resistant to the treatment with molecular Doxorubicin (Dox) and Dox-loaded mesoporous silica nanoparticles than in monolayer cultures. When grafted on CE chorioallantoic membrane, LS-ECM-based TECs induced angiogenic switch. These findings may have important implications for the diag-nosis and treatment of TNBC. The methodology established here is scalable and adaptable for pharmacological testing and cancer biology research of various metastatic and primary tumors.
Publisher: American Chemical Society (ACS)
Date: 10-2005
DOI: 10.1021/JP053511M
Abstract: A combination of colloidal crystal planarization, stabilization, and novel infiltration techniques is used to build a bimodal porous silica film showing order at both the micron and the nanometer length scale. An infiltration method based on the spin-coating of the mesophase precursor onto a three-dimensional polystyrene colloidal crystal film allows a nanometer control tuning of the filling fraction of the mesoporous phase while preserving the optical quality of the template. These materials combine a high specific surface arising from the nanopores with increased mass transport and photonic crystal properties provided by the order of the macropores. Optical Bragg diffraction from these type of hierarchically ordered oxides is observed, allowing performing of optical monitoring of the different processes involved in the formation of the bimodal silica structure.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NR00371A
Abstract: The protein corona of nanoparticles is becoming a tool to understand the relation between intrinsic physicochemical properties and extrinsic biological behaviour.
Publisher: American Chemical Society (ACS)
Date: 20-05-2008
DOI: 10.1021/CM702440N
Publisher: Royal Society of Chemistry (RSC)
Date: 23-06-2014
DOI: 10.1039/C4TB00418C
Publisher: Elsevier BV
Date: 09-2010
Publisher: Cold Spring Harbor Laboratory
Date: 09-01-2020
DOI: 10.1101/2020.01.08.898163
Abstract: Early stages of colonization of distant organs by metastatic cancer cells (micrometastasis) remain almost inaccessible to study due to lack of relevant experimental approaches. Here, we show the first 3D tissue engineered model of hepatic micrometastasis of triple negative breast cancer (TNBC). It reproduces characteristic histopathological features of the disease and reveals that metastatic TNBC cells colonize liver parenchymal and stromal extracellular matrix with different speed and by different strategies. These engineered tumors induce the angiogenic switch when grafted in vivo, confirming their metastatic-specific behaviour. Furthermore, we proved feasibility and biological relevance of our model for drug and nanoparticle testing and found a down-regulatory effect of the liver microenvironment of the sensitivity of TNBC cells to chemotherapeutic drug doxorubicin in free and nanoformulated forms. The convenient and affordable methodology established here can be translated to other types of metastatic tumors for basic cancer biology research and adapted for high-throughput assays.
Publisher: Elsevier BV
Date: 15-09-2009
DOI: 10.1016/J.TAAP.2009.06.011
Abstract: Macrophage recognition and ingestion of apoptotic cell corpses, a process referred to as programmed cell clearance, is of considerable importance for the maintenance of tissue homeostasis and in the resolution of inflammation. Moreover, macrophages are the first line of defense against microorganisms and other foreign materials including particles. However, there is sparse information on the mode of uptake of engineered nanomaterials by primary macrophages. In this study, mesoporous silica particles with cubic pore geometries and covalently fluorescein-grafted particles were synthesized through a novel route, and their interactions with primary human monocyte-derived macrophages were assessed. Efficient and active internalization of mesoporous silica particles of different sizes was observed by transmission electron microscopic and flow cytometric analysis and studies using pharmacological inhibitors suggested that uptake occurred through a process of endocytosis. Moreover, uptake of silica particles was independent of serum factors. The silica particles with very high surface areas due to their porous structure did not impair cell viability or function of macrophages, including the ingestion of different classes of apoptotic or opsonized target cells. The current findings are relevant to the development of mesoporous materials for drug delivery and other biomedical applications.
Publisher: American Chemical Society (ACS)
Date: 16-02-2009
DOI: 10.1021/JA8096477
Abstract: Hoogsteen-bonded tetrads and pentamers are formed by a large variety of organic molecules through H-donor and acceptor groups capable of inducing self-organization to form columnar and hexagonal mesophases. The biological importance of such macromolecular structures is exemplified by the assembly of guanosine-rich groups of telomere units and their implication in chromosomal replication. Folic acid is composed of a pterin group, chemically and structurally similar to guanine, conjugated to an l-glutamate moiety via a p-amino benzoic acid. Our aim has been to develop a delivery vehicle for folic acid and at the same time provide a novel synthetic route for ordered mesoporous materials without the use of hiphilic surfactants. We present a new nonsurfactant route for the synthesis of highly ordered mesoporous materials, based on the supramolecular templating of stacked arrays of the tetramer-forming pterin groups of folic acid under a variety of synthetic conditions. This method leads to hexagonally ordered mesoporous structures with gyroid, spherical, and chiral morphologies with pores on the order of 25-30 A in diameter and surface areas above 1000 m(2)/g. More importantly circular dichroism studies reveal that the folate template possesses a chiral signature within the pores in the as-synthesized solid and that chirality is transferred from the folate template to the pore surface via the aminopropyl triethoxysilane costructure directing agent used in the supramolecular assembly. This novel templating approach for ordered mesoporous materials breaks the hegemony of surfactant micellar systems for the preparation of these exciting high surface area solids and opens new opportunities for structural control, design of pore geometry, and novel applications.
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.BCP.2011.01.023
Abstract: Targeted drug therapy or "smart" drug delivery, potentially combined with simultaneous imaging modalities to monitor the delivery of drugs to specific tissues, is arguably the "holy grail" of pharmacology. Therapeutic approaches that exploit nanoparticles to deliver drugs selectively to cancer cells are currently considered one of the most promising avenues in the area of cancer therapeutics and imaging. The potential to deliver active chemotherapeutic drugs in the vicinity or directly within specific tumors via receptor mediated pathways, and to image tumors through the use of nanoparticles has been conceptually and experimentally shown for several classes of nanoparticles. Nanoparticles functionalized with the vitamin folic acid are of particular interest as a variety of malignant tumors are known to overexpress the folate receptor(s). Indeed, several nanoparticle architectures with improved retention time, administration route, biocompatibility, absorption, and clearance are being proposed and are in late stage clinical development. This commentary highlights some of the most important concepts related to nanoparticles and folate-mediated drug delivery and imaging in cancer research.
Location: Tanzania, United Republic of
Start Date: 04-2016
End Date: 04-2020
Amount: $674,352.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2019
End Date: 12-2019
Amount: $1,480,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2022
End Date: 02-2027
Amount: $4,997,903.00
Funder: Australian Research Council
View Funded Activity