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ABSTRACT In this article, a temperature- and pH-responsive delivery system based on block-copolymer-capped mesoporous silica nanoparticles (MSNs) is presented. A poly[2-(diethylamino)ethyl methacrylate)] (PDEAEMA)- b-poly( N-isopropyl acrylamide) (PNIPAM) shell on MSNs was obtained through the surface-initiated atom transfer radical polymerization. The block copolymer PDEAEMA- b-PNIPAM showed both temperature- and pH-responsive properties. The release of the loaded model molecules from PDEAEMA- b-PNIPAM-coated MSNs could be controlled by changes in the temperature or pH value of the medium. The as-desired drug-delivery carrier may be applied to biological systems in the future. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42395. [ABSTRACT FROM AUTHOR]

A facile strategy for the fabrication of multi-functional polymer/inorganic hybrid nanoparticles for efficient gene and drug co-delivery was developed. A therapeutic gene (p53 plasmid) and a chemotherapy drug (doxorubicin hydrochloride, DOX) were co-loaded simultaneously in hybrid nanoparticles during co-precipitation with high encapsulation efficiency. The prepared heparin-biotin/heparin/ CaCO3/calcium phosphate/ DNA/ DOX ( HPB/ HP/ CaCO3/ CaP/ DNA/ DOX) nanoparticles exhibited pH sensitivity and tumor-targeting property due to the presence of the CaCO3/ CaP inorganic component and biotin moiety in the polymer chain, respectively. For comparison, HPB/ HP/ CaCO3/ CaP/ DOX hybrid nanoparticles for drug delivery were also fabricated. The cell inhibition effects of different nanoparticles on HeLa cells were evaluated using methylthiazole tetrazolium assay. In vitro study indicated that the gene and drug co-delivery system ( HPB/ HP/ CaCO3/ CaP/ DNA/ DOX) showed a stronger cell growth inhibition effect as compared with the drug delivery system ( HPB/ HP/ CaCO3/ CaP/ DOX), indicating that HPB/ HP/ CaCO3/ CaP/ DNA/ DOX hybrid nanoparticles could effectively mediate gene transfection and deliver the drug. The hybrid nanoparticles with good biocompatibility have great promise for gene and drug co-delivery. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

ABSTRACT Polycarbonate microspheres TT-PC containing tetanus toxoid vaccine (TT) were prepared by the modified water-in-oil-in-water (W/O/W) solvent evaporation technique, using poly(trimethylene carbonate- co−5,5-dimethyl trimethylene carbonate) (P(TMC- co-DTC), or PC) as a polymeric carrier. TT release studies showed that the microspheres sustained a steady release rate of TT in the phosphate buffer saline solution (0.1 mol L−1, pH 7.4) in vitro for 60 days. In vivo cytotoxicity assays demonstrated that the polycarbonate microspheres had low toxicity and high safety in vivo in guinea pigs. Immunity and inoculation tests indicated that the TT-PC microspheres acted as an immunological adjuvant in vivo in guinea pigs. In guinea pigs attacked with an active tetanus toxoid, an injection of the TT-PC microspheres with a single-dose and booster vaccination induced high levels of antitoxin efficiencies in the blood serum, showing good immunoprotection. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 40048. [ABSTRACT FROM AUTHOR]

Novel random copolymers of 1,4-dioxane-2-one (DON) and 2,2-ethylenedioxy-1,3-propanediol carbonate (EOPDC) are synthesized in bulk at 120 °C using Sn(Oct)2 as a catalyst. The effects of different molar feed ratios of EOPDC/DON on the yield and molecular weight of the copolymers are investigated. The copolymers are obtained with a yield of 55.4-98%. The number-average molecular weight of the copolymer is 0.49-4.18 × 104 g mol−1 with a polydispersity of 1.52-1.68. The poly(DON- co-EOPDC)s obtained are characterized by FTIR, 1H NMR, and 13C NMR spectroscopy, gel-permeation chromatography (GPC), and DSC. The hydrolytic degradation of the copolymer in phosphate buffered saline (PBS) is also investigated. The results show that both the hydrophilicity and the degradation rate of the copolymers increase with increasing copolymer DON content. [ABSTRACT FROM AUTHOR]

A graphene oxide hydrogel (GOH) is fabricated via suspending the graphene oxide (GO) in water without any additional processing steps. At the hydrogel/air interface, a well-defined hydrogel membrane forms once the solvent is removed by vacuum drying. The microstructure of the resulting GOH film can be tailored by different dehydration approaches, as well as by varying the GO concentration in the hydrogel. This GOH exhibited pH-responsiveness and good mechanical properties. Meanwhile, the GOH presented good adsorption capacity to the organic dye rhodamine B and anionic chromate Cr2O72−. This GOH may find great potential in many fields, such as wastewater treatment, biodetection, etc. [ABSTRACT FROM AUTHOR]

We synthesized poly(amidoamine)s with pendant primary amines and flexible backbone (polymers 1-3) by Michael polyaddition of N- tert-butyloxycarbonyl (N-Boc) protected diamine to 1,6-Bis(acrylamido)hexane, followed by the deprotection of N-Boc under acidic conditions. The physicochemical properties of polymers 1-3, including buffer capacity, DNA-binding capacity, cytotoxicity, particle sizes, and zeta potentials of polycation/DNA complexes, were explored. All the three polymers possess high buffer capacity and excellent DNA-binding capacity. In vitro MTT assay revealed that these synthesized poly(amidoamine)s were less cytotoxic than commercial branched PEI (25 kDa). These poly(amidoamine)s with pendant primary amines and flexible backbone were evaluated as in vitro nonviral gene delivery vectors for 293T and COS-7 cells. All the three polymers exhibited high transfection efficiencies, which were even higher than branched PEI (25 kDa) at optimized conditions. Further evidences from confocal laser scanning microscope (CLSM) demonstrated that the high transfection efficiencies of polymers 1-3 were due to the efficient uptake and intracellular trafficking of plasmid DNA in the cells during the transfection. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012. [ABSTRACT FROM AUTHOR]

A new 'plug and play' polymeric template with the driving force of host-guest interaction between β-CD and naphthalene-modified functional groups was designed and studied. Multiple functional groups can be loaded into the template directly and conveniently. Importantly, the 'plug and play' effect of the polymeric template is reversible and the functional groups could be removed from the polymeric template conveniently by adding AD-HCl. The studies on the cell viability and phagocytosis proved that the loading and unloading process of this template could be realized in vitro. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012. [ABSTRACT FROM AUTHOR]

A series of amphiphilic diblock copolypeptides (ADCs), 5-(4-aminophenyl)-10,15,20-triphenyl-porphyrin (APP) conjugated poly( L-leucine)- block-polylysine (APP-LnKm) with different molar ratios of L-leucine unit and lysine unit were designed and synthesized. The optimized composition of the polypeptide was determined to be APP-L109K186, which has high fluorescence quantum yield and could self-assemble into micelles in an aqueous medium with mean particle size <30 nm. The in vitro study indicates that APP-L109K186 shows no significant dark cytotoxicity when the concentration is below 200 mg L−1 for HepG2 and HeLa cells. In contrast, the polymer exhibits apparent phototoxicity with low IC50 values toward HepG2 and HeLa cells, implying that the potential high photodynamic therapy efficacy of the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [ABSTRACT FROM AUTHOR]

Background To overcome extracellular barriers in gene therapy, controlled release technology has been adapted to protect DNA from degradation and maintain elevated DNA concentration. Although cell-penetrating peptides (CPPs) have been widely utilized to enhance the transfection efficiency of solution-based transfections, as far as we are aware, the effect of these peptides on substrate-mediated transfection has not yet been reported. Methods In the present study, the effect of a CPP, KALA, on the substrate-mediated gene delivery was studied. A fast degrading cholic acid functionalized star poly(DL-lactide) was used to fabricate Ca-P/DNA/KALA co-precipitates-deposited films and Ca-P/DNA/KALA co-precipitates-encapsulated films for mediating substrate-mediated transfection. The in vitro gene transfections in HEK293T and HepG2 cells mediated by the different films were investigated. The effect of KALA content on gene transfection was studied. Results Gene expression of film-mediated transfections could be significantly enhanced by the addition of KALA at a quite low content with a DNA/KALA ratio of 10 : 1. As a result of the surface erosion mechanism of the functionalized star poly(DL-lactide), our substrate-mediated transfection system could rapidly release Ca-P/DNA/KALA to mediate efficient gene expression. During the transfection, the degradation of the polymer films could be observed and the degradation did not show any unfavorable effects on gene expression. Conclusions The presence of a CPP could significantly enhance the gene expression of substrate-mediated transfections. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A peptide containing a RGD (arginine‐glycine‐aspartic acid) sequence as well as a hydrophobic N‐fluorenyl‐9‐methoxycarbonyl (FMOC) tail was prepared via a standard FMOC solid‐phase peptide synthesis technique. The supramolecular self‐assembly of such peptide through π–π stacking from FMOC tail can transfer the peptide aqueous solution into a three‐dimensional hydrogel. The biocompatibility of the peptide hydrogel was evaluated via clinical follow‐up and histological analysis. The data obtained demonstrated that the peptide hydrogel exhibited good biocompatibility when injected to the subconjunctival space and anterior chamber of rabbit, indicating a potential application in ophthalmology as an implantable drug delivery system for the treatment to ocular anterior segment diseases such as glaucoma, iridocyclitis, and keratopathy. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010 [ABSTRACT FROM AUTHOR]

Calcium‐phosphate/deoxyribose nucleic acid (Ca‐P/DNA) co‐precipitates were deposited on or encapsulated in fast‐degrading polymer films with surface erosion degradation mechanism to mediate cell transfection. The polymer, cholic acid functionalized star poly(DL‐lactide), was synthesized through the ring‐opening polymerization of DL‐lactide initiated by cholic acid. The releases of DNA from the Ca‐P/DNA co‐precipitates deposited film and the Ca‐P/DNA co‐precipitates encapsulated film were determined and compared. The in vitro gene transfections of HEK293 cells, Hela cells, and NIH 3T3 cells showed that the expression of pGL3‐Luc plasmid could be effectively mediated by the Ca‐P/DNA co‐precipitates deposited and encapsulated polymer films. In addition, the films did not exhibit any additional cytotoxicity to the cells during the transfections, indicating that the fast‐degrading polymer films have great potential in localized gene delivery. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [ABSTRACT FROM AUTHOR]

Thermosensitive and biotinylated biotin‐poly (N‐isopropylacrylamide‐co‐N‐hydroxymethylacrylamide)‐block‐poly(methyl methacrylate) (biotin‐P(NIPAAm‐co‐HMAAm)‐b‐PMMA) block copolymers were designed and synthesized. The conjugation of biotin molecule with the copolymer as well as the capability of easily functionalizing with ligands for pretargeting approach of the biotinylated multifunctional drug carrier was confirmed by a novel method called capillary electrophoresis immunoassay (CEIA) based on enhanced chemiluminescence (CL) detection. The biotin‐P(NIPAAm‐co‐HMAAm)‐b‐PMMA copolymer was capable of self‐assembling into nanometer‐sized micelle. The anticancer drug methotrexate (MTX), used as a model drug, was loaded in the self‐assembled micelles and the thermo‐triggered release behavior of MTX was investigated. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009 [ABSTRACT FROM AUTHOR]

Background To overcome the extracellular barriers in gene delivery and direct gene delivery to target tissues, substrate-mediated transfection, which sustains the release of naked DNA or vector/DNA complexes, and also supports cell growth, has been developed. Methods In the present study, polyamidoamine (PAMAM) dendrimer/DNA complexes encapsulated functional biodegradable polymer films for substrate-mediated gene delivery were prepared. To maintain the activity of DNA during dehydration, the dendrimer/DNA complexes were encapsulated in a water soluble polymer, poly α,β-[ N-(2-hydroxyethyl)-L-aspartamide], and then deposited on or sandwiched in functional polymer films with a fast degradation rate to mediate gene transfection. The in vitro gene transfections of pGL3-Luc and pEGFP-C1 plasmids in HEK293 cells mediated by different films were studied. For comparison, the transfection mediated by the film fabricated by conventional linear poly(DL-lactide) was also investigated. Results The expression of pGL3-Luc and pEGFP-C1 plasmids could effectively be mediated by the PAMAM/DNA complexes deposited or sandwiched polymer films, with transfection efficiencies comparable to that of solution-based transfections. The cells on the functionalized star poly(DL-lactide) film exhibited much higher gene expression compared to the cells on the conventional linear poly(DL-lactide) film because the fast degradation rate of star poly(DL-lactide) facilitated the access of PAMAM/DNA complexes for the cells seeded on the film. In addition, the films did not exhibit any additional cytotoxicity to the cells during the degradation and transfection. Conclusions The fast degrading functional polymer has great potential for localized transfection. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article presents a study on the development of temperature-sensitive poly(N-isopropylacrylamide) (PNIPAAm)/β-cyclodextrin-grafred polyethylenimine hydrogels for drug delivery. For the study, researchers purified NIPAAm through recrystallization from a mixed solvent of benzene and n-hexane. They found that the semi-interpenetrating network hydrogels resulted a higher swelling ratio at room temperature and manifester a more aggressive shrinking kinetics when the temperature was increased.