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Publications (3)13.93 Total impact

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    ABSTRACT: Thrombus formation and microbial invasion are two major complications that impede the widespread application of blood-contacting devices. The development of new materials that have blood compatibility and antibacterial adhesion activity has gained increased attention. In this study, a new class of polymers composed of hydrophilic dendronized polyethylene glycol (PEG) methacrylate and hydrophobic octyne monomethyl ether-glycidyl methacrylate was synthesized via click chemistry and free radical polymerization. Different polymers were synthesized by changing the ratio of the two monomers. The structures of the synthesized polymers were characterized by (1)H nuclear magnetic resonance and Fourier-transform infrared spectroscopy. Their physical properties such as molecular weight, polydispersity, and glass transition temperature were determined using gel permeation chromatography and differential scanning calorimetry. The synthesized polymers were coated on glass slides to prepare a series of polymeric surfaces. Contact angle measurements and attenuated total reflection Fourier-transform infrared spectroscopy analysis showed that the polymeric surfaces had long-lasting stability. The introduction of the monomer dendronized PEG methacrylate to the polymers greatly improved the hydrophilicity of the polymeric surfaces. The blood compatibility of the synthesized polymers was evaluated by protein (bovine serum albumin and fibrinogen) adsorption and platelet adhesion assays. Their antibacterial adhesion ability was investigated using the Gram-negative Pseudomonas aeruginosa and the Gram-positive Staphylococcus aureus. The results demonstrated that the amount of adsorbed protein, platelets, and bacteria on the polymeric surfaces decreased with increased content of the hydrophilic monomer dendronized PEG methacrylate in the polymers. However, no obvious difference was observed when such content exceeded 50 mol%. The results suggested that the new kind of polymer could be developed as a promising blood-contact coating material that may have extensive medical applications.
    Colloids and surfaces B: Biointerfaces 04/2012; 97:226-35. · 4.28 Impact Factor
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    ABSTRACT: The current paper reports the synthesis of a highly hydrophilic, antifouling dendronized poly(3,4,5-tris(2-(2-(2-hydroxylethoxy)ethoxy)ethoxy)benzyl methacrylate) (PolyPEG) brush using surface initiated atom transfer radical polymerization (SI-ATRP) on PDMS substrates. The PDMS substrates were first oxidized in H(2)SO(4)/H(2)O(2) solution to transform the Si-CH(3) groups on their surfaces into Si-OH groups. Subsequently, a surface initiator for ATRP was immobilized onto the PDMS surface, and PolyPEG was finally grafted onto the PDMS surface via copper-mediated ATRP. Various characterization techniques, including contact angle measurements, attenuated total reflection infrared spectroscopy, and X-ray photoelectron spectroscopy, were used to ascertain the successful grafting of the PolyPEG brush onto the PDMS surface. Furthermore, the wettability and stability of the PDMS-PolyPEG surface were examined by contact angle measurements. Anti-adhesion properties were investigated via protein adsorption, as well as bacterial and cell adhesion studies. The results suggest that the PDMS-PolyPEG surface exhibited durable wettability and stability, as well as significantly anti-adhesion properties, compared with native PDMS surfaces. Additionally, our results present possible uses for the PDMS-PolyPEG surface as adhesion barriers and anti-fouling or functional surfaces in biomedical applications.
    Colloids and surfaces B: Biointerfaces 06/2011; 88(1):85-92. · 4.28 Impact Factor
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    ABSTRACT: In this study, folate-functionalized hybrid polymeric nanoparticles (NPs) were prepared as carriers of low water solubility paclitaxel for tumor targeting, which were composed of monomethoxy-poly(ethylene glycol)-b-poly(lactide)-paclitaxel (MPEG-PLA-paclitaxel) and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)-folate (TPGS-FOL). NPs with various weight ratios of MPEG-PLA-paclitaxel and TPGS-FOL were prepared using a solvent extraction/evaporation method, which can also physically encapsulate paclitaxel. The size, size distribution, surface charge, and morphology of the drug-loaded NPs were characterized using a Zetasizer Nano ZS, scanning electron microscope (SEM), and atomic force microscopy (AFM). The encapsulation and drug loading efficiencies of these polymeric NPs are analyzed using high-performance liquid chromatography (HPLC) at 227 nm. The combination of covalent coupling and physical encapsulation is found to improve the loading of paclitaxel in NPs greatly. The in vitro antitumor activity of the drug-loaded NPs is assessed using a standard method of transcriptional and translational (MTT) assays against HeLa and glioma C6 cells. When the cells were exposed to NPs with the same paclitaxel weights, cell viability decreases in relation to the increase in TPGS-FOL in drug-loaded NPs. To investigate drug-loaded NP cellular uptake, the fluorescent dye coumarin-6 is utilized as a model drug and enveloped in NPs with 0 or 50% TPGS-FOL. Confocal laser scanning microscopy (CLSM) analysis shows that cellular uptake is lower for coumarin-6-loaded NPs with 0% TPGS-FOL than those with 50% TPGS-FOL. However, no difference for NIH 3T3 cells with normally expressed folate receptors is found. Results from in vitro antitumor activity and cellular uptake assay demonstrate that folic acid promotes drug-loaded NP cellular uptake through folate receptor-mediated endocytosis (RME). All of these results demonstrate that folate-decorated hybrid polymeric NPs are potential carriers for tumor-targeted drug delivery.
    Biomacromolecules 01/2011; 12(1):228-34. · 5.37 Impact Factor