Co-reporter:Yuzheng Wu;Haifeng Li;Zhouquan Rao;Huaqiang Li;Yan Wu;Jianhua Rong
Journal of Materials Chemistry B 2017 vol. 5(Issue 39) pp:7974-7984
Publication Date(Web):2017/10/11
DOI:10.1039/C7TB01824J
The controlled protein adsorption and delivery of thermosensitive poly(N-isopropylacrylamide) (PNIPAM) nanogels were investigated under different temperatures, pH values and ionic strengths by using bovine serum albumin (BSA) as a model protein. The BSA adsorption in deionized water was due to one or several of four contributions, i.e. the electrostatic attraction between BSA and nanogels, the seizing action of nanogels to BSA, the hydrophobic interaction between BSA and nanogels, and the physical diffusion of BSA, depending on the temperature and pH value. At 37 °C and pH 4.0, the largest BSA adsorption of 23.5 μg mg−1 was achieved by the above four contributions following electrostatic attraction (48%) > seizing action (21%) > hydrophobic interaction (16%) > physical diffusion (15%). The BSA adsorption in different sodium chloride solutions exhibited a maximum of 17.2 μg mg−1 at 0.03 M, which was influenced by the charge shielding of Na+ ions, salting out of BSA and nanogel aggregation. Most adsorbed BSA molecules were distributed on the nanogel surface except a few standing in the nanogel interior. The adsorbed BSA could be controllably delivered by tailoring the temperature and pH value, and with the aid of sodium dodecyl sulfate. The conformation of BSA adsorbed in hydrochloric acid solution (pH 4.0) significantly changed due to the acid environment and the electrostatic attraction between BSA and nanogels, but it could be completely recovered when BSA was delivered in deionized water or physiological saline. This work is instructive to design the controllable adsorption and delivery of proteins by using PNIPAM-based hydrogels as carriers.
Co-reporter:Yuzheng Wu, Wen Xiong, Hanyu Zhou, Haifeng Li, Guoguang Xu, Jianhao Zhao
Polymer Degradation and Stability 2016 Volume 126() pp:22-30
Publication Date(Web):April 2016
DOI:10.1016/j.polymdegradstab.2016.01.009
The biodegradation of poly(butylene succinate) (PBS) films by compost microorganisms were studied for insight into the composition of water soluble products and their effect on the surroundings, including medium pH, microorganism viability and mung beans germination. After degradation by compost microorganisms adhering to the film surface, PBS films showed a lot of cracks and holes, accompanied by a continuous decrease of remaining mass and molecular weight. In the initial two weeks, the water soluble products acidified the medium from pH7.2 to pH5.2 and inhibited the microbe growth. With the assimilation of these products as carbon sources by microorganisms, the medium pH value gradually returned to neutral and the microbes fast proliferated as well. The ultra performance liquid chromatography-mass spectrum analysis confirmed that the water soluble products were composed of 1,4-butanediol (B), succinic acid (S), and their oligomers BS, BSB, SBS, BSBS, BSBSB and SBSBS, whose contents depended on their production, microbial assimilation and instability. The germination test revealed that the water soluble products themselves were little hazardous to mung beans, but the acidified medium significantly inhibited the mung beans germination. Fortunately, PBS-degrading microorganisms were able to recover the safe neutral environment by assimilating these acid products.
Co-reporter:Ruicong Li;Xiaoting Zhang;Qiuyu Zhang;Huahua Liu;Jianhua Rong;Mei Tu;Rong Zeng
Journal of Applied Polymer Science 2016 Volume 133( Issue 9) pp:
Publication Date(Web):
DOI:10.1002/app.43072
ABSTRACT
In order to develop a potential drug sustained delivery carrier suitable for wound healing, a series of β-cyclodextrin conjugated hyaluronan hydrogels (β-CD-HA) with adjustable crosslink densities were synthesized and characterized, meanwhile the delivery kinetics and mechanism of diclofenac as a model anti-inflammatory drug from these hydrogels were investigated. By controlling the feeding molar ratio of β-CD/HA, a β-CD substitution degree of 4.65% was obtained by 1H-NMR analysis. The incorporation of β-CD modification had little effect on the internal porous structure, water swelling ratio, and rheological property of HA hydrogel, which however were influenced by the crosslink density. Although the crosslink density had an influence on the drug loading and release profile by altering the water swelling property, the interaction between β-CD and drug was the primary factor for the high loading capacity and long-term sustained delivery of diclofenac. The semiempirical equation fit showed that the release of diclofenac from HA-based hydrogels followed a pseudo-Fickian diffusion mechanism. By the aid of β-CD and controlled crosslink density, a β-CD-HA hydrogel with a diclofenac sustained delivery period of over 28 days and desirable physicochemical properties was achieved, which will be a promising drug sustained delivery carrier for wound healing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43072.
Co-reporter:Guoguang Xu;Xiao Liu;Yanqun Lin;Guoshan He;Wanjuan Wang;Wen Xiong;Haiying Luo;Zhong Liu
Journal of Applied Polymer Science 2015 Volume 132( Issue 25) pp:
Publication Date(Web):
DOI:10.1002/app.42064
ABSTRACT
In this study, the thermal hydrolysis of the poly(l-lactic acid) (PLLA) films was investigated for its potential use as a food-packaging ecomaterial. The surface morphology, mass loss, molecular weight, thermal properties, and medium pH were routinely investigated; meanwhile, in particular, the composition and cytotoxicity of the water-soluble degradation products were studied. The changes in the mass loss and molecular weight revealed a random chain-scission mechanism. Differential scanning calorimetry analysis implied that the hydrolysis preferentially took place in the amorphous region. The medium pH decreased with time because of the accumulation of acid water-soluble products in the medium. Liquid chromatography/mass spectrometry analysis proved that these products were composed of 1–13 lactic acid units, in which the content of l-lactic acid increased with time and reached 9.71 mmol/L after hydrolysis for 84 days. The in vitro cell culture indicated that the water-soluble degradation products from the PLLA films had no cytotoxicity to human umbilical vein endothelial cells. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42064.
Co-reporter:Chunhong Luo, Guoguang Xu, Xinghui Wang, Mei Tu, Rong Zeng, Jianhua Rong, Jianhao Zhao
Materials Science and Engineering: C 2015 Volume 46() pp:316-324
Publication Date(Web):1 January 2015
DOI:10.1016/j.msec.2014.10.066
•New self-reinforcing HA hydrogels with a dually cross-linked network were developed.•Self-reinforcing HA hydrogels greatly enhanced the mechanical properties.•Self-reinforcing HA hydrogels prolonged the sustained delivery of BSA.•The self-reinforcing mechanism and BSA diffusion mechanism were discussed.•Self-reinforcing HA hydrogels had no cytotoxicity to 3T3 fibroblast cells.A series of self-reinforcing hyaluronan hydrogels were developed to improve mechanical properties and protein sustained delivery thanks to a dually cross-linked network. Hyaluronan gel particles (HGPs, 1–5 μm in diameter) with different cross-linking densities, i.e. HGPs-1.5, HGPs-3 and HGPs-15, were prepared in an inverse emulsion system and used as the reinforcing phase after glycidyl methacrylation, while glycidyl methacrylated hyaluronan with a substitution degree of 45.2% was synthesized as the matrix phase. These two phases were cross-linked under ultraviolet irradiation to form self-reinforcing hyaluronan hydrogels (srHAs) that showed typical cross-linked structure of HGPs connecting the matrix phase by cross-section observation. In comparison to hyaluronan bulk gels and their blends with HGPs, srHAs distinctly enhanced the mechanical properties and BSA long-term sustained delivery, especially srHA-1.5 showed the highest compressive modulus of 220 ± 15 kPa and the slowest BSA delivery (67% release at 14 d). The 3T3 fibroblast cell culture showed that all the srHAs had no cytotoxicity.
Co-reporter:Chunhong Luo, Jianhao Zhao, Mei Tu, Rong Zeng, Jianhua Rong
Materials Science and Engineering: C 2014 Volume 36() pp:301-308
Publication Date(Web):1 March 2014
DOI:10.1016/j.msec.2013.12.021
•HA microgels with different crosslink densities were prepared.•The crosslinker content had little effect on the morphology and size of HA microgels.•The crosslink density increased with the crosslinker content.•Higher crosslink density led to lower water swelling ratio and slower degradation.•Increasing the crosslink density decreased the BSA loading but prolonged its delivery.Hyaluronan (HA) microgels with different crosslink network, i.e. HGPs-1, HGPs-1.5, HGPs-3, HGPs-6 and HGPs-15, were synthesized using divinyl sulfone (DVS) as the crosslinker in an inverse microemulsion system for controlling the sustained delivery of bovine serum albumin (BSA). With increasing the crosslinker content, the average particle size slightly increased from 1.9 ± 0.3 μm to 3.6 ± 0.5 μm by dynamic laser scattering analysis. However, the crosslinker content had no significant effect on the morphology of HA microgels by scanning and transmission electron microscopes. Fourier transform infrared spectroscopy and elemental analysis proved more sulfur participated in the crosslink reaction when raising the crosslinker amount. The water swelling test confirmed the increasing crosslink density with the crosslinker content by calculating the average molecular weight between two crosslink points to be 8.25 ± 2.51 × 105, 1.26 ± 0.43 × 105, 0.96 ± 0.09 × 105, 0.64 ± 0.03 × 105, and 0.11 ± 0.01 × 105 respectively. The degradation of HA microgels by hyaluronidase slowed down by enhancing the crosslink density, only about 5% of HGPs-15 was degraded as opposed to over 90% for HGPs-1. BSA loading had no obvious influence on the surface morphology of HA microgels but seemed to induce their aggregation. The increase of crosslink density decreased the BSA loading capacity but facilitated its long-term sustained delivery. When the molar ratio of DVS to repeating unit of HA reached 3 or higher, similar delivery profiles were obtained. Among all these HA microgels, HGPs-3 was the optimal carrier for BSA sustained delivery in this system because it possessed both high BSA loading capacity and long-term delivery profile simultaneously.
Co-reporter:Wanqing Han;Mei Tu;Rong Zeng;Zhengang Zha;Changren Zhou
Journal of Applied Polymer Science 2013 Volume 128( Issue 3) pp:
Publication Date(Web):
DOI:10.1002/app.38177
Abstract
A biomimetic nanofibrous poly(L-lactide) scaffold strengthened by nanohydroxyapatite particles was fabricated via a thermally induced phase separation technique. Scanning electron microscopy results showed that nanohydroxyapatite particles uniformly dispersed in the nanofibrous poly(L-lactide) scaffold (50–500 nm in fiber diameter) with slight aggregation at a high nHA content, but showed no influence on the interconnected macroporous and nanofibrous structure of the scaffold. The nanofibrous poly(L-lactide) scaffold presented a specific surface area of 34.06 m2 g−1, which was much higher than that of 2.79 m2 g−1 for the poly(L-lactide) scaffold with platelet structure. Moreover, the specific surface area of the nanofibrous scaffold was further enhanced by incorporating nanohydroxyapatite particles. With increasing the nanohydroxyapatite content, the compressive modulus and amount of bovine serum albumin adsorbed on the surface of the nanofibrous composite scaffold were markedly improved, as opposed to the decreased crystallinity. In comparison to poly(L-lactide) scaffold, both the nanofibrous poly(L-lactide) and poly(L-lactide)/nanohydroxyapatite scaffolds exhibited a faster degradation rate for their much larger specific surface area. The culture of bone mesenchymal stem cell indicated that the composite nanofibrous poly(L-lactide) scaffold with 50 wt % nanohydroxyapatite showed the highest cells viability among various poly(L-lactide)-based scaffolds. The strengthened biomimetic nanofibrous poly(L-lactide)/nanohydroxyapatite composite scaffold will be a potential candidate for bone tissue engineering. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Co-reporter:Jianhao Zhao, Wanqing Han, Minjian Tang, Mei Tu, Rong Zeng, Zhihong Liang, Changren Zhou
Materials Science and Engineering: C 2013 Volume 33(Issue 3) pp:1546-1553
Publication Date(Web):1 April 2013
DOI:10.1016/j.msec.2012.12.060
Poly(l-lactide) films with a nano-structured surface by immobilizing chitosan nanofibers (CSNFs) for improving the cell affinity were fabricated via a solid-liquid phase separation technique. The successful grafting of CSNFs on the surface of poly(l-lactide) films was confirmed by the binding energy of N1s at 398.0 eV in the X-ray photoelectron spectroscopy and the amide I and II bands of chitosan at 1650 and 1568 cm− 1 in the Fourier transform infrared spectroscopy. Compared with the poly(l-lactide) film, the hydrophilicity was improved with a lower water contact angle of 83.3 ± 1.9° and 75.3 ± 2.5° for the CSNFs-grafted and CSNFs-grafted/anchored poly(l-lactide) films respectively. The scanning electron microscopy and atomic force microscopy analyses showed that the grafted CSNFs with 50–500 nm in diameter were randomly arranged on the film surface and entangled with the anchored CSNFs on the outermost layer. The 3T3 fibroblasts culture indicated cells tended to attach and stretch along the CSNFs on the film surface. The cell viability measurement revealed that among all the samples, the film with both grafted and anchored CSNFs exhibited the highest cell proliferation rate that was twice as much of the poly(l-lactide) film at 7 d. Herein, engineering a nano-structured surface by solid–liquid phase separation will be a promising tool for surface modification of biomaterials.Highlights► A surface nano-structured poly(l-lactide) film with chitosan nanofibers was prepared. ► Grafted and anchored chitosan nanofibers were obtained by different treatment ways. ► Hydrophilicity was improved by immobilizing chitosan nanofibers on the film surface. ► Cell viability was enhanced on modified poly(l-lactide) film with chitosan nanofibers. ► Cells tended to attach and stretch along chitosan nanofibers on the film surface.
Co-reporter:Jianhao Zhao, Wanqing Han, Mei Tu, Songwei Huan, Rong Zeng, Hao Wu, Zhengang Cha, Changren Zhou
Materials Science and Engineering: C 2012 Volume 32(Issue 6) pp:1496-1502
Publication Date(Web):1 August 2012
DOI:10.1016/j.msec.2012.04.031
A biomimetic nanofibrous poly(l-lactide) scaffold decorated by chitosan nanofiber network inside the macropores was fabricated using a dual thermally induced phase separation technique. The first phase separation was used to build a nanofibrous poly(l-lactide) scaffold with interconnected macropores, where chitosan nanofibers about 500 nm in diameter were incorporated via the second phase separation. The content of nanofibrous chitosan was determined to be 5.76 in weight percentage by elemental analysis. The composite scaffold showed the highest protein adsorption of 7225 ± 116 μg/cm3 and the most hydroxyapatite crystal deposition in the mineralization. Compared with non-nanofibrous poly(l-lactide) scaffold, nanofibrous poly(l-lactide) scaffold exhibited a much faster degradation, but it could be restrained by the introduced chitosan nanofibers. The bone mesenchymal stem cell culture results indicated that the cells would rather attach and stretch along the chitosan nanofibers in the composite scaffold that showed the highest viability and the best cytocompatibility may be attributed to the biomimetic nanofibrous network and good cell affinity of chitosan nanofibers.Highlights► A nanofibrous poly(l-lactide) scaffold with chitosan nanofiber network was prepared. ► Chitosan nanofibers had no effect on the structure of poly(l-lactide) scaffold. ► The composite scaffold showed the best protein adsorption and mineralization ability. ► Fast degradation of nanofibrous poly(l-lactide) was resisted by chitosan nanofibers. ► Chitosan nanofibers favored cell attachment and growth in the macropore space.
Co-reporter:Jianhao Zhao, Chunhong Luo, Yuqi Chen, Dan Wu, Chaoxuan Shen, Wanqing Han, Mei Tu, Rong Zeng
Carbohydrate Polymers 2011 Volume 86(Issue 2) pp:806-811
Publication Date(Web):15 August 2011
DOI:10.1016/j.carbpol.2011.05.026
Heparin-conjugated hyaluronan (HA-Hp) microgels with different heparin content, i.e., 1%, 5% and 10% (w/w), were synthesized by an inverse emulsion polymerization technique for the controlled release of bone morphogenetic protein-2 (BMP-2). A heparin conjugation percentage of about 90% was obtained by elemental analysis. Hyaluronan microgels showed a smooth surface and dense network, whereas HA-Hp microgels exhibited a rougher surface with holes and concaves, and a looser internal structure with increasing the heparin content instead. However, the major microgel size of about 3 μm was independent of the heparin amount. Among the samples, HA-Hp-10% microgels existed the highest equilibrium swelling ratio of 11.8 due to its least cross-linking network. A higher BMP-2 loading efficiency and a slower release profile with increasing the heparin content indicated the conjugated heparin in HA-Hp microgels was in favor of BMP-2 binding and the sustained delivery maybe attributed to the electrostatic interaction between heparin and BMP-2.Highlights► Heparin-conjugated hyaluronan microgels are prepared for BMP-2 controlled release. ► Rougher surface and looser interior are formed by increasing heparin content. ► The water equilibrium swelling ratio of microgels increases with heparin content. ► The BMP-2 loading efficiency of microgels increases with heparin content. ► A slower BMP-2 release profile is obtained by increasing heparin content.
![Poly[oxy(1,4-dioxo-1,4-butanediyl)oxy-1,4-butanediyl]](http://img.cochemist.com/ccimg/26300/26247-20-1.png)
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![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2.png)
![Poly[oxy[(1S)-1-methyl-2-oxo-1,2-ethanediyl]]](http://img.cochemist.com/ccimg/26200/26161-42-2_b.png)
