羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶的制备及吸附重金属离子

以N-异丙基丙烯酰胺和羧甲基壳聚糖(CMCS)为原料成功制备了羧甲基壳聚糖/聚(N-异丙基丙烯酰胺)半互穿网络水凝胶,通过扫描电镜(SEM)﹑测溶胀比对凝胶性能进行了表征。考察了羧甲基壳聚糖对于凝胶内部微观结构的影响及其对Fe3+吸附性能的变化。发现随着CMCS用量的增加,凝胶内部结构的孔状网络结构更为明显,水凝胶对Fe3+离子吸附能力增强。     

交联剂结构对可生物降解壳聚糖水凝胶性能影响的研究

通过NaIO₄氧化制备不同的醛基多糖,结果表明,在同一氧化条件下制备的氧化多糖醛基含量不同。以醛基多糖和羧甲基壳聚糖(CMCS)为原料通过席夫碱反应制备了一系列多糖水凝胶。结果表明,不同醛基多糖交联的CMCS水凝胶在结构性能上具有较大的差异性,包括：孔径、吸水性和力学强度。细胞毒性测试表明,不同结构的多糖水凝胶均具有较好的细胞相容性。该研究有望依据水凝胶应用的目标性能合理地定制多糖水凝胶的制备方案,为多糖水凝胶进一步的功能改性及在伤口敷料、细胞支架等生物医学领域的应用奠定基础。     

聚氨酯-Ch水凝胶的制备及其作为伤口敷料的性能

以2,4-二羟基苯甲醛(DDBA)为扩链剂,丙烯酸羟乙酯(HEA)为封端剂制备了含有醛基的水性聚氨酯(DPU),在温和的条件下引入不同含量的羧甲基壳聚糖(CMCh)溶液合成了CMCh席夫碱,接着其与丙烯酰胺经自由基反应合成了聚氨酯-羧甲基壳聚糖席夫碱水凝胶(DPU-Ch).通过FTIR、SEM、力学性能、溶胀保水性、抗菌性和血液相容性测试等对水凝胶结构和性能进行了表征.结果表明,水凝胶的机械性能随着CMCh含量的增加先增大后减小,水凝胶显示出良好的溶胀能力和保水能力;水凝胶对革兰氏阳性和阴性细菌菌株均显示出良好的抗菌性能;水凝胶溶血率均低于5％,表明其具有良好的细胞相容性,小鼠成纤维细胞(NIH3T3)存活率在90％以上证明其细胞毒性较低.当CMCh添加量为DPU树脂固含量的4％时,DPU-Ch水凝胶综合性能最佳,溶胀比为10.58,24 h失水率为31.1％,压缩强度为0.70 MPa,溶血率为2.4％,细胞存活率为101％±1.7％,抗菌性能良好.     

羧甲基壳聚糖/氧化魔芋葡甘聚糖复合海绵的制备与性能评价

以羧甲基壳聚糖(CMCS)和氧化魔芋葡甘聚糖(OKGM)为原料,采用冷冻干燥法制备羧甲基壳聚糖/氧化魔芋葡甘聚糖(CMCS/OKGM)复合海绵,通过FTIR、~1HNMR、SEM等对其结构进行表征,通过吸水率、孔隙率、透气率、对NIH-3T3细胞增殖的影响、抗菌能力及急性全身毒性等测试来评价其性能。确定CMCS/OKGM复合海绵的最优制备工艺为:先采用高碘酸钠氧化制备OKGM,再按5∶5的体积比将质量浓度均为5%的CMCS溶液和OKGM溶液混合,加入2%的甘油作为塑化剂,冷冻干燥即得。CMCS/OKGM复合海绵具有良好的吸水率、孔隙率、透气率、抗菌活性、生物安全性且能促进表皮细胞增殖,是优良的医用慢性伤口敷料基础底料。     

温度及pH敏感性聚乙烯醇/羧甲基壳聚糖水凝胶的制备与性能研究

以聚乙烯醇(PVA)和羧甲基壳聚糖(CMCh)为原料,采用60Co-γ射线辐照交联制备聚乙烯醇/羧甲基壳聚糖(PVA/CMCh)水凝胶;研究了PVA与CMCh的配比、温度、pH及离子强度等对PVA/CMCh水凝胶溶胀率的影响。结果表明适当配比的PVA/CMCh水凝胶具有一定的温度、pH及离子敏感性。该水凝胶在5~20°C时具有较高的溶胀率,温度在20°C以上溶胀率较低,并且有一定的可逆性;水凝胶在pH较低(pH<4.0)和较高(pH>6.0)时溶胀率均较大,而当pH为4.0~6.0时溶胀率较小,显示出一定的pH敏感性。     

羧甲基壳聚糖及其纤维的制备及表征

用氯乙酸改性处理壳聚糖(CS)制备羧甲基壳聚糖(CMCS),采用湿法纺丝法制备CMCS纤维,考察了纺丝原液浓度、醋酸水溶液体积分数、凝固时间对CMCS纤维力学性能的影响;通过傅里叶变换红外光谱、X射线衍射以及热失重分析对CS,CMCS及其纤维进行表征。结果表明:CMCS发生了羧甲基取代,同时CMCS结晶度降低;CMCS纤维结构中含有结合水,热分解温度为270℃;纺丝原液CMCS的质量分数为50%,醋酸水溶液的体积分数为2%、凝固时间为12 min时,CMCS纤维的断裂强度达0.644 cN/dtex。     

自组装法制备CMCS/PEG纳米粒子及其pH值响应性研究

以壳聚糖(CS)为原料与氯乙酸反应制备羧甲基壳聚糖(CMCS),再将聚乙二醇(PEG)和CMCS以不同的质量比溶解在不同pH值的溶液中,通过氢键相互作用自组装形成CMCS/PEG纳米粒子,并研究其粒径大小与二者配比和溶液pH值之间的关系。结果表明,不同配比下的粒子粒径均随pH值的增大先增大后减小;当pH5时,在相同pH值溶液中,随着PEG比例的增加,粒子的粒径先减小后增大,在pH=1.22、PEG∶CMCS=4∶1时粒径最小,约为160nm;当pH≥5时,在相同pH值溶液中,粒径随PEG用量的增加而增大;通过自组装法制备的CMCS/PEG纳米粒子粒径大小具有pH值响应性。     

羧甲基壳聚糖-丙烯酸高吸水性树脂的制备及性能

以羧甲基壳聚糖(CMCS)为基体,丙烯酸(AA)为接枝单体,过硫酸铵(APS)为引发剂,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备出羧甲基壳聚糖-丙烯酸高吸水性树脂(CMCS-AA SAP)。研究了CMCS粘度对树脂吸液性能的影响。结果表明,一定范围内,随着CMCS粘度的增加,CMCS-AA高吸水性树脂网络结构更加紧密,吸水性能得到提高。合成工艺优化结果显示,在交联剂(MBA)用量为0.025%(以AA质量为基准,下同),引发剂(APS)用量为0.093 75%,AA中和度为80%的条件下,树脂的吸水倍率达1 011.21 g/g,吸盐倍率达85.74 g/g,树脂有着良好的pH敏感性。     

聚氨酯-羧甲基壳聚糖席夫碱水凝胶的制备与性能

将2,4-二羟基苯甲醛（DDBA）作为扩链剂，丙烯酸羟乙酯(HEA)作为封端剂制备了含有醛基的水性聚氨酯（DPU），在温和的条件下引入羧甲基化壳聚糖（CMCh）合成了聚氨酯-CMCh席夫碱，再由自由基聚合法引入聚丙酰胺合成了聚氨酯-羧甲基壳聚糖席夫碱水凝胶（DPU-Ch）。通过FTIR、SEM、力学性能、溶胀保水试验、抗菌试验和血液相容性测试等对水凝胶结构和性能进行表征。结果表明，水凝胶的机械性能随着CMCh质量分数的增加而提升，同时水凝胶也显示出良好的溶胀能力和保水能力；当CMCh添加量为2%时，水凝胶对革兰氏阳性和阴性细菌菌株均显示出良好的抗菌性能；水凝胶溶血率均低于5%表明其具有良好的细胞相容性，NIH3T3细胞存活率在90%以上证明其没有细胞毒性，因此在生物医疗领域中具有潜在的应用前景。     

还原氧化石墨烯负载纳米银/聚乙烯醇型抗菌水凝胶的制备与性能

以聚乙烯醇（PVA）、氧化石墨烯（GO）、硝酸银为原料,在不添加引发剂和交联剂的情况下,使用物理交联法（冷冻-解冻法）制得了一系列还原氧化石墨烯（rGO）负载不同质量分数纳米银（AgNPs）/PVA型抗菌水凝胶（rGO-AgNPs/PVA）(PGA-1～PGA-6,阿拉伯数字代表AgNPs的质量分数)。通过FTIR、SEM、TGA、电子万能材料试验机和流变仪对水凝胶的结构、形貌、力学性能和流变性能进行了表征,并对其生物性能进行了测试。结果表明,rGO的加入增强了PVA水凝胶的机械强度,rGO-AgNPs/PVA抗菌水凝胶断裂伸长率比PVA水凝胶提高约60%,拉伸应变达到125%。PVA水凝胶的储能模量和损耗模量均低于rGO-AgNPs/PVA水凝胶;rGO与AgNPs协同抗菌,PGA-3(AgNPs质量分数0.33%)对大肠杆菌和金黄色葡萄球菌的抑菌带宽度分别约为4.5和5.5 mm;相较于PVA水凝胶,rGO-AgNPs/PVA水凝胶的孔洞增多,r GO通过π-π作用形成网络结构,r GO-Ag NPs/PVA水凝胶显示出多孔互联的微观结构。     

Photosensitive antibacterial and cytotoxicity performances of a TiO2/carboxymethyl chitosan/poly(vinyl alcohol) nanocomposite hydrogel by in situ radiation construction

Nano‐TiO₂/carboxymethyl chitosan (CMCS)/poly(vinyl alcohol) (PVA) ternary nanocomposite hydrogels were prepared by freezing–thawing cycles and electron‐beam radiation with PVA, CMCS, and nano‐TiO₂ as raw materials. The presence of nano‐TiO₂ nanoparticles in the composite hydrogels was confirmed by thermogravimetry, Fourier transform infrared spectroscopy, and X‐ray powder diffraction. Field emission scanning electron microscopy images also illustrated that the TiO₂/CMCS/PVA hydrogel exhibited a porous and relatively regular three‐dimensional network structure; at the same time, there was the presence of embedded nano‐TiO₂ throughout the hydrogel matrix. In addition, the nano‐TiO₂/CMCS/PVA composite hydrogels displayed significant antibacterial activity with Escherichia coli and Staphylococcus aureus as bacterial models. The antibacterial activity was demonstrated by the antibacterial circle method, plate count method, and cell density method. Also, with the Alamar Blue assay, the cytotoxicity of the composite hydrogel materials to L929 cells was studied. The results suggest that these materials had no obvious cytotoxicity. Thus, we may have developed a novel, good biocompatibility hydrogel with inherent photosensitive antibacterial activity with great potential for applications in the fields of cosmetics, medical dressings, and environmental protection. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44150.     

A novel pH‐sensitive and freeze‐thawed carboxymethyl chitosan/poly(vinyl alcohol) blended hydrogel for protein delivery

BACKGROUND: Blended hydrogels are widely applied in medical fields. They can provide many advantages, such as biocompatibility and biodegradability. Many materials and methods are used to obtain blended hydrogels. In this work, carboxymethyl chitosan (CMCS) and poly(vinyl alcohol) (PVA) blended hydrogels were prepared using the freezing and thawing technique. The properties of the hydrogels prepared, i.e. gel fraction, swelling and pH‐responsive behaviors, were investigated. RESULTS: The gel fraction increased with increasing time of freezing and thawing as determined through gravimetric analysis. It was also found that the equilibrium degree of swelling improved obviously due to the addition of CMCS compared to pure PVA hydrogel. The blended hydrogel with composition CMCS/PVA 80/20 (by weight) possessed the highest swelling ratio. The results of the influence of pH values on the swelling behavior showed that minimum swelling ratios of the hydrogels occurred near the isoelectric point of CMCS. Protein release studies were performed under various pH conditions: the release was much slower under acid than under basic conditions. The release showed a burst in the first 15 h and then steadily increased. CONCLUSION: The addition of CMCS can improve the physical properties of pure PVA hydrogels and provide pH sensitivity. It is concluded that PVA hydrogels containing CMCS could be potentially applied as oral delivery systems for protein drugs. Copyright © 2009 Society of Chemical Industry     

Gamma irradiation synthesis and characterization of AgNP/gelatin/PVA hydrogels for antibacterial wound dressings

An antibacterial hydrogel wound dressing was successfully synthesized by the gamma irradiation method. A gelatin solution was mixed with a poly(vinyl alcohol) (PVA) solution of similar concentrations at different weight ratios of 100 : 0, 80 : 20, and 60 : 40 w/w, and irradiated at 30, 40, or 50 kGy. The testing of physical properties showed that the addition of PVA could improve both durability and mechanical integrity. The 60 : 40 hydrogels irradiated at 30 kGy were optimal, and chosen to add silver nitrate at 0.25, 0.50, 0.75, or 1.00 wt % (based on the solid content) to improve the antibacterial properties. After gamma irradiation, silver nanoparticles (AgNPs) were formed. The AgNP/gelatin/PVA hydrogels were characterized for physical properties, cytotoxicity, and antibacterial activity. The AgNP/gelatin/PVA hydrogels could be used as antibacterial wound dressings because they exhibited appropriate physical properties, noncytotoxicity, and could inhibit the growth of tested bacteria. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41138.     

Preparation and antibacterial effects of PVA‐PVP hydrogels containing silver nanoparticles

The poly(vinyl alcohol)/poly(N‐vinyl pyrrolidone) (PVA–PVP) hydrogels containing silver nanoparticles were prepared by repeated freezing–thawing treatment. The silver content in the solid composition was in the range of 0.1–1.0 wt %, the silver particle size was from 20 to 100 nm, and the weight ratio of PVA to PVP was 70 : 30. The influence of silver nanoparticles on the properties of PVA–PVP matrix was investigated by differential scanning calorimeter, infrared spectroscopy and UV–vis spectroscopy, using PVA–PVP films containing silver particles as a model. The morphology of freeze‐dried PVA–PVP hydrogel matrix and dispersion of the silver nanoparticles in the matrix was examined by scanning electron microscopy. It was found that a three‐dimensional structure was formed during the process of freezing–thawing treatment and no serious aggregation of the silver nanoparticles occurred. Water absorption properties, release of silver ions from the hydrogels and the antibacterial effects of the hydrogels against Escherichia coli and Staphylococcus aureus were examined too. It was proved that the nanosilver‐containing hydrogels had an excellent antibacterial ability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 125–133, 2007     

Radiation synthesis and characterization of poly(vinyl alcohol)/poly(N-vinyl-2-pyrrolidone) based hydrogels containing silver nanoparticles

A series of PVA/PVP based hydrogels at different compositions were prepared by gamma irradiation. The gel fraction degree of swelling were investigated. Highly stable and uniformly distributed silver nanoparticles have been obtained onto hydrogel networks. The morphology and structure of (PVA/PVP) hydrogel and dispersion of the silver nanoparticles in the polymeric matrix were examined by scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR), respectively. The formation of silver nanoparticles has been confirmed by ultraviolet visible (UV–vis) spectroscopy. A strong characteristic absorption peak was found to be around 420 nm for the silver nanoparticles in the hydrogel nanocomposite. The X-ray diffraction pattern confirmed the formation of silver nanoparticles with average particle size of 12 nm. The diameter distribution of silver nanoparticles was determined by dynamic light scattering DLS. Transmission electron microscope (TEM) showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network and the mean size of silver nanoparticles ranging is 23 nm. The good swelling properties and antibacterial of PVA/PVP-Ag hydrogel suggest that it can be a good candidate as wound dressing.     

High strength and toughness of double physically cross-linked hydrogels composed of polyvinyl alcohol and calcium alginate

The weak mechanical properties of hydrogels, especially physically cross-linked hydrogels are usually a major factor to hinder their application. To solve this problem, in this work, we prepared a high strength and toughness of double physically cross-linked (PDN) hydrogels composed of crystalline domain cross-linked polyvinyl alcohol (PVA) and Ca²⁺-cross-linked alginate (Alg). With a further annealing treatment, the noncovalent cross-linked network via the formed crystalline promote the as-prepared PDN PVA/Alg hydrogel to exhibit well mechanical properties with the tensile strength of ~1.94 MPa, elongation at break of ~607% and Young's modulus of ~0.45 MPa (above 70 wt% of water content). By analyzing the mechanism of improving the hydrogel mechanical properties, it is found that annealing can effectively improve the crystallinity of PVA in the hydrogel, and then greatly improve the mechanical properties of the hydrogel. This provides a general method for improving the mechanical properties of PVA PDN hydrogels. In addition, the PDN PVA/Alg hydrogel was also proved to have good ionic conductivity of 1.70 S m⁻¹. These desirable properties make the prepared physically cross-linked hydrogels promising materials for medical and biosensing fields.     

Biodegradability, antimicrobial activity and properties of PVA/PVP hydrogels prepared by γ-irradiation

Polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) hydrogel has been prepared by using γ-irradiation technique. In the present study the conclusion on miscibility of PVA/PVP blends, confirmed qualitatively and quantitatively by using Fourier transform infrared spectroscopy and differential scanning calorimetry, respectively. PVA and PVP are found to form a thermodynamically miscible pair. The physical properties such as gel fraction and water absorption performance of the prepared hydrogels were measured, it was found that the gel fraction increases with increasing irradiation dose while the swelling of PVA/PVP blended hydrogels nearly tends to increase with increasing PVP content and reduced with enhanced irradiation doses. The hydrogel pore structure of various PVA/PVP compositions were tested with SEM. Ability of PVA/PVP hydrogels to absorb and release antimicrobial compounds was tested using amoxicillin as an antibacterial and ketoconazole as an antifungal. Antimicrobial activity of PVA/PVP hydrogels was examined using four bacteria, and four fungi. No antibacterial or antifungal activities of non-loaded PVA/PVP of various compositions were detected while the loading ones found to have antimicrobial activity. Results showed resistance of Pseudomonas aeruginosa and Candida albicans to PVA/PVP, while Bacillus subtilis was very sensitive. Biodegradation of PVA/PVP hydrogels was investigated by burial method in two types of local soils (clay and sandy soils). The highest degradation rate was found to be achieved using clay soil. Also, effect of irradiation dose on its biodegradability was tested. The results showed that the radiation prepared PVA/PVP hydrogels can be use as biomaterials.     

High performances of dual network PVA hydrogel modified by PVP using borax as the structure-forming accelerator

A dual network hydrogel made up of polyvinylalcohol (PVA) crosslinked by borax and polyvinylpyrrolidone (PVP) was prepared by means of freezing-thawing circles. Here PVP was incorporated by linking with PVA to form a network structure, while the introduction of borax played the role of crosslinking PVA chains to accelerate the formation of a dual network structure in PVA/PVP composite hydrogel, thus endowing the hydrogel with high mechanical properties. The effects of both PVP and borax on the hydrogels were evaluated by comparing the two systems of PVA/PVP/borax and PVA/borax hydrogels. In the former system, adding 4.0% PVP not only increased the water content and the storage modulus but also enhanced the mechanical strength of the final hydrogel. But an overdose of PVP just as more than 4.0% tended to undermine the structure of hydrogels, and thus deteriorated hydrogels’ properties because of the weakened secondary interaction between PVP and PVA. Likewise, increasing borax could promote the gel crosslinking degree, thus making gels show a decrease in water content and swelling ratio, meanwhile shrinking the pores inside the hydrogels and finally enhancing the mechanical strength of hydrogels prominently. The developed hydrogel with high performances holds great potential for applications in biomedical and industrial fields.     

Development of Gelatin Based Inorganic Nanocomposite Hydrogels for Inactivation of Bacteria

In this investigation, silver nanocomposite hydrogels were developed by using acrylamide and biodegradable gelatin. Silver nanoparticles were generated throughout the hydrogel networks using in situ method by incorporating Ag⁺ ions and the subsequent treatment with sodium borohydride. The effect of gelatin on the swelling studies was investigated. The hydrogel synthesized silver nanocomposites were characterized by using Fourier transform infrared, UV–Visible spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron and transmission electron microscopy techniques. The biodegradable gelatin-based silver nanocomposite hydrogels were tested for antibacterial properties. The results indicate that these biodegradable silver nanocomposite hydrogels can be useful in medical applications, as antibacterial agents.     

Preparation and characterization of acrylic acid/itaconic acid hydrogel coatings containing silver nanoparticles

Hydrogel silver nanocomposites have been used in applications with excellent antibacterial performance. Acrylic acid (AA)/itaconic acid (IA) hydrogels silver nanocomposites were prepared and applied as a coating on a textile substrate. Hydrogel matrices were synthesized first by the polymerization of an AA/IA aqueous (80/20 v/v) solution and mixed with 2‐2‐azobis(2‐methylpropionamide) diclorohydrate and N,N′‐methylene bisacrylamide until the hydrogel was formed. Silver nanoparticles were generated throughout the hydrogel networks with an in situ method via the incorporation of the silver ions and subsequent reduction with sodium borohydride. Cotton (C) and cotton/polyester (CP) textile fibers were then coated with these hydrogel silver nanocomposites. The influence of these nanocomposite hydrogels on the properties of the textile fiber were investigated by infrared spectroscopy (attenuated total reflectance), scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and antibacterial tests against Pseudomona aeruginosa and Staphylococcus aureus. The better conditions, in which no serious aggregation of the silver nanoparticles occurred, were determined. It was proven that the textiles coated with hydrogels containing nanosilver had an excellent antibacterial abilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2713–2721, 2013