ORCID Profile
0000-0001-6785-6645
Current Organisations
California State University
,
Max Planck Institute of Colloids and Interfaces
,
Donghua University
,
Universidade da Madeira
,
Tsinghua University
,
University of Michigan
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Publisher: Informa UK Limited
Date: 07-2013
DOI: 10.2147/IJN.S46177
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.BIOMATERIALS.2012.11.010
Abstract: We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped gold nanoparticles (Gd-Au DENPs) for dual mode computed tomography (CT)/magnetic resonance (MR) imaging applications. In this study, amine-terminated generation five poly(amidoamine) dendrimers (G5.NH₂) modified with gadolinium (Gd) chelator and polyethylene glycol (PEG) monomethyl ether were used as templates to synthesize gold nanoparticles (AuNPs). Followed by sequential chelation of Gd(III) and acetylation of the remaining dendrimer terminal amine groups, multifunctional Gd-Au DENPs were formed. The formed Gd-Au DENPs were characterized via different techniques. We show that the formed Gd-Au DENPs are colloidally stable and non-cytotoxic at an Au concentration up to 50 μM. With the coexistence of two radiodense imaging elements of AuNPs and Gd(III) within one NP system, the formed Gd-Au DENPs display both r₁ relaxivity for MR imaging mode and X-ray attenuation property for CT imaging mode, which enables CT/MR dual mode imaging of the heart, liver, kidney, and bladder of rat or mouse within a time frame of 45 min. Furthermore, in vivo biodistribution studies reveal that the Gd-Au DENPs have an extended blood circulation time and can be cleared from the major organs within 24 h. The strategy to use facile dendrimer technology to design dual mode contrast agents may be extended to prepare multifunctional platforms for targeted multimode molecular imaging of various biological systems.
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.BIOMATERIALS.2013.03.009
Abstract: We report the synthesis and characterization of folic acid (FA)-modified multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) loaded with gadolinium (Gd) for targeted dual mode computed tomography (CT)/magnetic resonance (MR) imaging of tumors. In this work, amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) modified with Gd(III) chelator, polyethylene glycol (PEG) monomethyl ether, and PEGylated FA were used as templates to entrap gold nanoparticles (AuNPs). Further chelation of Gd(III) ions and acetylation of the remaining dendrimer terminal amines led to the formation of multifunctional FA-targeted Au DENPs loaded with Gd(III) (Gd-Au DENPs-FA). The formed Gd-Au DENPs-FA probes were characterized via different techniques. We show that the Gd-Au DENPs-FA probes with an Au NP core size of 4.0 nm are water dispersible, stable under different pH and temperature conditions, and cytocompatible in the given concentration range. With the co-existence of AuNPs and Gd(III) ions within the single multifunctional particles, Gd-Au DENPs-FA displayed high X-ray attenuation intensity and reasonable r1 relaxivity. These properties of the particles enabled them to be used as dual mode nanoprobes for targeted CT/MR imaging of cancer cells in vitro and xenograft tumor model in vivo via FA receptor-mediated active targeting pathway. The strategy to design multifunctional nanoprobes using the versatile dendrimer nanotechnology may be extended to design various dual mode or multimode imaging agents for accurate diagnosis of different types of cancer.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3BM60138B
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2PY20993D
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB00543A
Abstract: Multifunctional 99m Tc-labeled dendrimer-entrapped gold nanoparticles modified with different surface groups can be used for preferential SPECT/CT imaging of different organs.
Publisher: American Chemical Society (ACS)
Date: 26-02-2013
DOI: 10.1021/LA4001363
Abstract: We report a facile approach to using laponite (LAP) nanodisks as a platform for efficient delivery of doxorubicin (DOX) to cancer cells. In this study, DOX was encapsulated into the interlayer space of LAP through an ionic exchange process with an exceptionally high loading efficiency of 98.3 ± 0.77%. The successful DOX loading was extensively characterized via different methods. In vitro drug release study shows that the release of DOX from LAP/DOX nanodisks is pH-dependent, and DOX is released at a quicker rate at acidic pH condition (pH = 5.4) than at physiological pH condition. Importantly, cell viability assay results reveal that LAP/DOX nanodisks display a much higher therapeutic efficacy in inhibiting the growth of a model cancer cell line (human epithelial carcinoma cells, KB cells) than free DOX drug at the same DOX concentration. The enhanced antitumor efficacy is primarily due to the much more cellular uptake of the LAP/DOX nanodisks than that of free DOX, which has been confirmed by confocal laser scanning microscope and flow cytometry analysis. The high DOX payload and enhanced antitumor efficacy render LAP nanodisks as a robust carrier system for different biomedical applications.
Publisher: American Chemical Society (ACS)
Date: 29-07-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TB00286F
Abstract: Multifunctional PEI-entrapped gold nanoparticles modified with lactobionic acid enable efficient targeted dual mode CT/MR imaging of human hepatocellular carcinoma.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TB20399A
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0NR00833H
Abstract: In molecular biology, polymerase chain reaction (PCR) has played an important role but suffers a general problem with low efficiency and specificity. Development of suitable additives to improve the PCR specificity and efficiency and the understanding of the PCR enhancing mechanism still remain a great challenge. Here we report the use of polyethyleneimine (PEI)-modified multiwalled carbon nanotubes (MWCNTs) with different surface charge polarities as a novel class of enhancers to improve the specificity and efficiency of PCR. The materials used included the positively charged PEI-modified MWCNTs (CNT/PEI), the neutral CNT/PEI modified with acetic anhydride (CNT/PEI.Ac), and the negatively charged CNT/PEI modified with succinic anhydride (CNT/PEI.SAH). We show that the specificity and efficiency of an error-prone two-round PCR are greatly impacted by the surface charge polarity of the PEI-modified MWCNTs. Positively charged CNT/PEI could significantly enhance the specificity and efficiency of PCR with an optimum concentration as low as 0.39 mg L(-1), whereas neutral CNT/PEI.Ac had no such effect. Although negatively charged CNT/PEI.SAH could enhance the PCR, the optimum concentration required (630 mg L(-1)) was more than 3 orders of magnitude higher than that of positively charged CNT/PEI. The present study suggests that the PCR enhancing effect may be primarily based on the electrostatic interaction between the positively charged CNT/PEI and the negatively charged PCR components, rather than only on the thermal conductivity of MWCNTs.
Publisher: Elsevier BV
Date: 02-2013
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.BIOMATERIALS.2012.10.071
Abstract: We report a facile approach to fabricating electrospun drug-loaded organic/inorganic hybrid nanofibrous system for antibacterial applications. In this study, nano-hydroxyapatite (n-HA) particles loaded with a model drug, amoxicillin (AMX) were dispersed into poly(lactic-co-glycolic acid) (PLGA) solution to form electrospun hybrid nanofibers. The loading of AMX onto n-HA surfaces (AMX/n-HA) and the formation of AMX/n-HA/PLGA composite nanofibers were characterized using different techniques. We show that AMX can be successfully adsorbed onto the n-HA surface and the formed AMX/n-HA/PLGA composite nanofibers have a uniform and smooth morphology with improved mechanical durability. Cell viability assay and cell morphology observation reveal that the formed AMX/n-HA/PLGA composite nanofibers are cytocompatible. Importantly, the loaded AMX within the n-HA/PLGA hybrid nanofibers shows a sustained release profile and a non-compromised activity to inhibit the growth of a model bacterium, Staphylococcus aureus. With the significantly reduced burst-release profile, good cytocompatibility, improved mechanical durability, as well as the remained antibacterial activity, the developed AMX/n-HA/PLGA composite nanofibers should find various potential applications in the fields of tissue engineering and pharmaceutical science.
Publisher: Wiley
Date: 28-02-2013
Abstract: We report the use of multifunctional dendrimer-modified multi-walled carbon nanotubes (MWCNTs) for targeted and pH-responsive delivery of doxorubicin (DOX) into cancer cells. In this study, amine-terminated generation 5 poly(amidoamine) (PAMAM) dendrimers modified with fluorescein isothiocyanate (FI) and folic acid (FA) were covalently linked to acid-treated MWCNTs, followed by acetylation of the remaining dendrimer terminal amines to neutralize the positive surface potential. The formed multifunctional MWCNTs (MWCNT/G5.NHAc-FI-FA) were characterized via different techniques. Then, the MWCNT/G5.NHAc-FI-FA was used to load DOX for targeted and pH-responsive delivery to cancer cells overexpressing high-affinity folic acid receptors (FAR). We showed that the MWCNT/G5.NHAc-FI-FA enabled a high drug payload and encapsulation efficiency both up to 97.8% and the formed DOX/MWCNT/G5.NHAc-FI-FA complexes displayed a pH-responsive release property with fast DOX release under acidic environment and slow release at physiological pH conditions. Importantly, the DOX/MWCNT/G5.NHAc-FI-FA complexes displayed effective therapeutic efficacy, similar to that of free DOX, and were able to target to cancer cells overexpressing high-affinity FAR and effectively inhibit the growth of the cancer cells. The synthesized multifunctional dendrimer-modified MWCNTs may be used as a targeted and pH-responsive delivery system for targeting therapy of different types of cancer cells.
Publisher: Wiley
Date: 15-03-2013
Abstract: We report a facile approach to fabricating low-generation poly(amidoamine) (PAMAM) dendrimer-stabilized gold nanoparticles (Au DSNPs) functionalized with folic acid (FA) for in vitro and in vivo targeted computed tomography (CT) imaging of cancer cells. In this study, amine-terminated generation 2 PAMAM dendrimers were employed as stabilizers to form Au DSNPs without additional reducing agents. The formed Au DSNPs with an Au core size of 5.5 nm were covalently modified with the targeting ligand FA, followed by acetylation of the remaining dendrimer terminal amines to endow the particles with targeting specificity and improved biocompatibility. Our characterization data show that the formed FA-modified Au DSNPs are stable at different pH values (5-8) and temperatures (4-50 °C), as well as in different aqueous media. MTT assay data along with cell morphology observations reveal that the FA-modified Au DSNPs are noncytotoxic in the particle concentration range of 0-3000 nM. X-ray attenuation coefficient measurements show that the CT value of FA-modified Au DSNPs is much higher than that of Omnipaque (a clinically used CT contrast agent) at the same concentration of the radiodense elements (Au or iodine). Importantly, the FA-modified Au DSNPs are able to specifically target a model cancer cell line (KB cells, a human epithelial carcinoma cell line) over-expressing FA receptors and they enable targeted CT imaging of the cancer cells in vitro and the xenografted tumor model in vivo after intravenous administration of the particles. With the simple synthesis approach, easy modification, good cytocompatibility, and high X-ray attenuation coefficient, the FA-modified low-generation Au DSNPs could be used as promising contrast agents for targeted CT imaging of different tumors over-expressing FA receptors.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM16851K
Publisher: Informa UK Limited
Date: 02-2012
DOI: 10.2147/IJN.S28947
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3AY41331D
Publisher: American Chemical Society (ACS)
Date: 07-08-2018
Publisher: American Chemical Society (ACS)
Date: 19-02-2013
DOI: 10.1021/AM302883M
Abstract: We report the facile hydrothermal synthesis and surface functionalization of branched polyethyleneimine (PEI)-coated iron oxide nanoparticles (Fe3O4-PEI NPs) for biomedical applications. In this study, Fe3O4-PEI NPs were synthesized via a one-pot hydrothermal method in the presence of PEI. The formed Fe3O4-PEI NPs with primary amine groups on the surface were able to be further functionalized with polyethylene glycol (PEG), acetic anhydride, and succinic anhydride, respectively. The formed pristine and functionalized Fe3O4-PEI NPs were characterized via different techniques. We showed that the sizes of the Fe3O4-PEI NPs were able to be controlled by varying the mass ratio of Fe(II) salt and PEI. In addition, the formed Fe3O4-PEI NPs with different surface functionalities had good water dispersibility, colloidal stability, and relatively high R2 relaxivity (130-160 1/(mM·s)). Cell viability assay data revealed that the surface PEGylation and acylation of Fe3O4-PEI NPs rendered them with good biocompatibility in the given concentration range, while the pristine aminated Fe3O4-PEI NPs started to display slight toxicity at the concentration of 50 μg/mL. Importantly, macrophage cellular uptake results demonstrated that both PEGylation and acetylation of Fe3O4-PEI NPs were able to significantly reduce the nonspecific macrophage uptake, likely rendering the particles with prolonged circulation time. With the proven hemocompatibility and rich amine conjugation chemistry, the Fe3O4-PEI NPs with different surface functionalities may be applied for various biomedical applications, especially for magnetic resonance imaging and therapy.
Publisher: Wiley
Date: 12-10-2012
DOI: 10.1002/APP.38444
Publisher: American Chemical Society (ACS)
Date: 05-08-2021
No related grants have been discovered for Xiangyang Shi.