A simple strategy was developed to prepare a tough, self-healing, antibacterial and moldable hydrogel by introducing the natural polyphenolic compound tannic acid(TA) as a cross-linking center for hydrogen bonds. Poly...A simple strategy was developed to prepare a tough, self-healing, antibacterial and moldable hydrogel by introducing the natural polyphenolic compound tannic acid(TA) as a cross-linking center for hydrogen bonds. Polyvinyl alcohol(PVA)-TA hydrogel was prepared by physical mixing using PVA as a main component and TA as a cross-linker. There were two types of physical cross linking bonds in the PVA-TA hydrogel network, which were weaker hydrogen bonds between PVA molecular chains and stronger hydrogen bonds between PVA and TA molecules. The mechanical properties and self-healing ability could be adjusted by changing the contents of PVA and TA. The hydrogel possessed not only high mechanical strength(305 kPa tensile strength and 864 kPa compressive strength), moldability and excellent self-healing properties(95% selfhealing efficiency) but also good antibacterial abilities against S. aureus and E. coli. In addition, after soaking the dried hydrogel in 90 ℃ deionized water for 4 h, they could also regain their self-healing ability to a certain extent. The hydrogels have potential applications in the biomedical fields.展开更多
A series of novel water soluble chitosan derivatives as gene vectors was synthesized. The delivery systems were tested for their ability to form complexes with plasmid DNA by utilizing agarose gel electrophoresis, par...A series of novel water soluble chitosan derivatives as gene vectors was synthesized. The delivery systems were tested for their ability to form complexes with plasmid DNA by utilizing agarose gel electrophoresis, particle size analysis, zeta potential measurement and scanning electron microscopy. Furthermore, cytotoxicity of chitosan derivatives and transfection efficiency of polyplexes were evaluated in vitro. The experimental results showed that the novel chitosan derivatives had lower cytotoxicity, good DNA condensation, and higher transfection efficiencies compared to chitosan in both 293T and HeLa cell lines. It was indicated that these chitosan derivatives were promising candidates for non-viral gene vectors.展开更多
A novel quaternary ammonium chitosan hydrogel modified by poly（amidoamine）（PAMAM） dendrimer was prepared by using glutaraldehyde as a cross-linker. The hydrogel was characterized by Fourier transform infrared spec...A novel quaternary ammonium chitosan hydrogel modified by poly（amidoamine）（PAMAM） dendrimer was prepared by using glutaraldehyde as a cross-linker. The hydrogel was characterized by Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. The results confirmed its highly porous three-dimensional network structure. The swelling test of hydrogel proved that it had excellent swelling and p H-sensitive properties. The increasing PAMAM content or quaternization degree led to the increase in swelling properties. And the hydrogel with lower cross-linking agent concentration or quaternary ammonium chitosan concentration exhibited better swelling properties. The antibacterial results indicated that with the increase in the PAMAM content, quaternary ammonium chitosan concentration or cross-linking agent concentration, the hydrogels showed better antibacterial activities against both Staphylococcus aureus（S. aureus） and Escherichia coli（E. coli）. Thus, the hydrogel could serve as a promising antibacterial material in the future.展开更多
Superabsorbent hydrogels were prepared successfully from N-succinyl chitosan grafted poly（acrylic acid-co-acrylamide）. The potassium persulfate（KPS）, N, N＇-methylenebisacrylamide（MBA） were used as the initiator...Superabsorbent hydrogels were prepared successfully from N-succinyl chitosan grafted poly（acrylic acid-co-acrylamide）. The potassium persulfate（KPS）, N, N＇-methylenebisacrylamide（MBA） were used as the initiator and crosslinker, respectively. Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM） were used to confirm the porous network structure of superabsorbent hydrogel. The effects of reaction parameters on the swelling behaviors of the superabsorbent hydrogels were investigated. The results indicated that water absorbency increased first, and then decreased gradually with the increase in the contents of monomer（AA＋AM）, KPS, MBA or acrylamide. The product had excellent water absorbency of 1375 g/g in distilled water and 83 g/g in 0.9wt% NaCl solution. Simultaneously, the superabsorbent hydrogels were p H sensitive. The antibacterial activities of the hydrogels against Escherichia coli（E. coli） were improved effectively because of polyamidoamine（PAMAM） dendrimer absorbed in the hydrogels.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.51773161,51303145,51373130,and 21975057)the Special Project of Technological Innovation of Hubei Province(No.2019ABA115)
文摘A simple strategy was developed to prepare a tough, self-healing, antibacterial and moldable hydrogel by introducing the natural polyphenolic compound tannic acid(TA) as a cross-linking center for hydrogen bonds. Polyvinyl alcohol(PVA)-TA hydrogel was prepared by physical mixing using PVA as a main component and TA as a cross-linker. There were two types of physical cross linking bonds in the PVA-TA hydrogel network, which were weaker hydrogen bonds between PVA molecular chains and stronger hydrogen bonds between PVA and TA molecules. The mechanical properties and self-healing ability could be adjusted by changing the contents of PVA and TA. The hydrogel possessed not only high mechanical strength(305 kPa tensile strength and 864 kPa compressive strength), moldability and excellent self-healing properties(95% selfhealing efficiency) but also good antibacterial abilities against S. aureus and E. coli. In addition, after soaking the dried hydrogel in 90 ℃ deionized water for 4 h, they could also regain their self-healing ability to a certain extent. The hydrogels have potential applications in the biomedical fields.
基金Funded by the National Natural Science Foundation of China(Nos.21204071,51273156)the Natural Science Foundation of Hubei Province(2014CFB833)the Innovation Research Fund of Wuhan university of Technology(20121049720006)
文摘A series of novel water soluble chitosan derivatives as gene vectors was synthesized. The delivery systems were tested for their ability to form complexes with plasmid DNA by utilizing agarose gel electrophoresis, particle size analysis, zeta potential measurement and scanning electron microscopy. Furthermore, cytotoxicity of chitosan derivatives and transfection efficiency of polyplexes were evaluated in vitro. The experimental results showed that the novel chitosan derivatives had lower cytotoxicity, good DNA condensation, and higher transfection efficiencies compared to chitosan in both 293T and HeLa cell lines. It was indicated that these chitosan derivatives were promising candidates for non-viral gene vectors.
基金Funded by the National Natural Science Foundation of China(Nos.51303145,51273156,51373130)
文摘A novel quaternary ammonium chitosan hydrogel modified by poly（amidoamine）（PAMAM） dendrimer was prepared by using glutaraldehyde as a cross-linker. The hydrogel was characterized by Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. The results confirmed its highly porous three-dimensional network structure. The swelling test of hydrogel proved that it had excellent swelling and p H-sensitive properties. The increasing PAMAM content or quaternization degree led to the increase in swelling properties. And the hydrogel with lower cross-linking agent concentration or quaternary ammonium chitosan concentration exhibited better swelling properties. The antibacterial results indicated that with the increase in the PAMAM content, quaternary ammonium chitosan concentration or cross-linking agent concentration, the hydrogels showed better antibacterial activities against both Staphylococcus aureus（S. aureus） and Escherichia coli（E. coli）. Thus, the hydrogel could serve as a promising antibacterial material in the future.
基金Funded by the National Natural Science Foundation of China(Nos.51303145,51273156,and 51373130)
文摘Superabsorbent hydrogels were prepared successfully from N-succinyl chitosan grafted poly（acrylic acid-co-acrylamide）. The potassium persulfate（KPS）, N, N＇-methylenebisacrylamide（MBA） were used as the initiator and crosslinker, respectively. Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM） were used to confirm the porous network structure of superabsorbent hydrogel. The effects of reaction parameters on the swelling behaviors of the superabsorbent hydrogels were investigated. The results indicated that water absorbency increased first, and then decreased gradually with the increase in the contents of monomer（AA＋AM）, KPS, MBA or acrylamide. The product had excellent water absorbency of 1375 g/g in distilled water and 83 g/g in 0.9wt% NaCl solution. Simultaneously, the superabsorbent hydrogels were p H sensitive. The antibacterial activities of the hydrogels against Escherichia coli（E. coli） were improved effectively because of polyamidoamine（PAMAM） dendrimer absorbed in the hydrogels.
文摘目的探索病原宏基因组二代测序(metagenomic next-generation sequencing,mNGS)在HPV感染、宫颈癌等宫颈相关疾病研究中的潜在价值。方法从6例宫颈癌或癌前病变患者中采集宫颈拭子标本;提取DNA后,分别进行病原mNGS和ⅡB型限制性内切酶相关DNA位点(2bRAD)测序,比较2种方法的微生物物种定量注释结果、高丰度物种检测能力及14种高危型HPV的检测能力,从而评估病原mNGS的宫颈微生态评价能力。对病原mNGS的宿主基因组数据进行染色体拷贝数变异(copy number variation,CNV)分析,比较临床病理结果与mNGS-CNV结果的一致性。为进一步探究病原mNGS的检测能力,在23例无宫颈疾病和存在不同等级宫颈病变的患者样本中进行初步验证。结果微生物定量注释结果显示,mNGS和2bRAD对于高丰度细菌物种的检出基本一致。对与宫颈癌高度相关的14种高危型HPV的分析结果显示,mNGS获得了与临床微生物实验室常规检测完全一致的结果。对mNGS的人源核酸数据进行CNV分析显示,3例宫颈癌中有1例存在CNV异常。此外,利用病原mNGS对存在宫颈病变和无宫颈病变患者的宫颈拭子进行分析显示,卷曲乳杆菌丰度、CNV阳性率和高危型HPV阳性率在两组患者之间存在差异,普雷沃菌属的某些物种可能与发生高级别病变和宫颈癌的高风险相关。结论病原mNGS作为一种无创且高效的病原微生物检测技术,能通过一次检查同时得到菌群微生态、HPV感染状态及宿主染色体稳定性3方面的信息,从而对健康和宫颈疾病患者进行鉴别,因此有望为HPV感染和宫颈癌筛查和诊断开辟新途径。
