三油酸甘油酯在共聚物水凝胶膜上的沉积作用

以N-乙烯吡咯烷酮、甲基丙烯酸羟乙酯以及甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯为原料,采用本体共聚法制备共聚物水凝胶角膜接触镜材料,通过材料样品在三油酸甘油酯溶液中浸泡前后的浓度变化,计算沉积量,评价人眼泪液组分三油酸甘油酯在共聚物水凝胶角膜接触镜材料上的沉积作用。结果表明,三油酸甘油酯的沉积量随溶液浓度增大、沉积温度升高、沉积时间延长而增大;共聚物水凝胶材料中N-乙烯吡咯烷酮组分的含量越大,沉积量越大;而甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯组分导致三油酸甘油酯的沉积量减小,以甲基丙烯酸甲酯最为明显。     

AM与HEMA共聚制备水凝胶接触镜材料及其溶胀性能

采用丙烯酰胺(AM)与甲基丙烯酸β-羟乙酯(HEMA)进行本体共聚制备水凝胶接触镜材料,研究了水凝胶的溶胀性能及其温度和pH值敏感性。结果表明,引发剂过氧化苯甲酰(BPO)用量为反应单体总质量的0.3%、反应温度80℃,产物溶胀之后为无色透明的玻璃状水凝胶;共聚物水凝胶具有较好的pH值敏感性,水凝胶在酸性溶液中溶胀,在碱性溶液中收缩:含有AM的水凝胶,其pH值敏感性较大:随AM的含量增大,共聚物水凝胶的溶胀速度和饱和含水量增大,随温度升高,水凝胶的饱和含水量下降,共聚物水凝胶中AM的含量对其温度敏感性无显著影响:SEM照片显示,AM与HEMA共聚物存在均匀的纤维状结构,并且共聚物中AM的含量越大,这种纤维状结构越大、越明显。     

NVP-HEMA-AM三元共聚物水凝胶对氯霉素的缓释作用

采用本体共聚法制备了丙烯酰胺(AM)与甲基丙烯酸-2羟-基乙酯(HEMA)以及N-乙烯基吡咯烷酮(NVP)共聚物水凝胶,研究了AM-HEMA-NVP共聚物水凝胶对广谱抗菌药物氯霉素的缓释作用。结果表明,随氯霉素溶液浓度增大、NaC l浓度降低、温度升高以及NVP或者AM组分的含量增大,AM-HE-MA-NVP三元共聚物水凝胶对氯霉素的吸收量增大;随AM-HEMA-NVP三元共聚物水凝胶中NVP或者AM组分含量的增大,氯霉素的释放速度明显增大;氯霉素从水凝胶中缓释的动力学可采用Fick扩散动力学描述,其释放过程受水凝胶溶胀过程以及氯霉素扩散过程控制。     

温敏型水凝胶的制备及溶胀特性

采用N-异丙基丙烯酰胺(NIPA)与N-乙烯基-2-吡咯烷酮(NVP)为共聚单体,以N,N-亚甲基双丙烯酰胺(BIS)为交联剂,过硫酸钾(KPS)为引发剂,通过化学交联的方法在水溶液中制备出P(NIPA-co-NVP)共聚物水凝胶。分别探讨了单体配比、交联剂用量等实验条件对水凝胶的温敏特性和溶胀性能的影响。利用傅里叶红外(FT-IR)对共聚物水凝胶的结构进行了表征。通过实验可知:当交联剂BIS和引发剂KPS分别为单体用量的5%和0.8%,制备的水凝胶具有较高的转化率、较好的机械强度和共聚性质。共聚物水凝胶中NVP含量越高,溶胀率越大,升温时溶胀率下降程度越大,自然条件下脱水速率越快;BIS用量越大,溶胀率越小,保水率越高,需要更长时间达到溶胀平衡。     

共聚物水凝胶角膜接触镜材料的初期脱水行为

以N-乙烯基吡咯烷酮、甲基丙烯酸羟乙酯以及甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯为原料,制备共聚物水凝胶角膜接触镜材料,建立了膜状水凝胶材料的脱水模型,采用重量法和热失重法研究了该材料的初期脱水行为.结果表明,水凝胶膜的初期脱水速度与其交联密度的平方成反比;共聚物水凝胶中N-乙烯基吡咯烷酮的含量越大,脱水速率越大;甲基丙烯酸甲酯、甲基丙烯酸乙酯以及甲基丙烯酸丁酯的含量越大,脱水速率越低,以甲基丙烯酸乙酯最明显;在初期脱水阶段,水凝胶膜的脱水行为可用一级动力学描述.     

壳聚糖交联聚甲基丙烯酸水凝胶对二价铜离子的吸附

以甲基丙烯酸为单体、壳聚糖为交联剂、过硫酸钾为引发剂,通过自由基聚合制备了聚甲基丙烯酸水凝胶,利用扫描电镜对水凝胶内部结构进行表征。考察了Cu~(2+)质量浓度、水凝胶质量、水凝胶中壳聚糖质量分数、溶液pH值、吸附温度及时间等不同条件对水凝胶吸附Cu~(2+)吸附量的影响。发现当Cu~(2+)质量浓度越大、水凝胶质量越小、吸附时间越长时,水凝胶对Cu~(2+)吸附量越大;壳聚糖质量分数为7%、吸附溶液pH值为6、吸附温度为25℃时,水凝胶对Cu~(2+)吸附量较大。     

β-环糊精/海藻酸钠水凝胶的制备及性能研究

将海藻酸钠(SA)和β-环糊精(β-CD)共混制备了复合水凝胶,并讨论了交联剂浓度、原料配比对水凝胶溶胀性能的影响。结果表明,当两者的共混比例为1∶2、w(交联剂)为6%、交联时间为1h时,水凝胶的溶胀性能较好。水凝胶在pH=1.2时的溶胀率仅为1.2,而在pH=7.4时的溶胀率达到14.2,具有良好的pH敏感性。以牛血清蛋白(BSA)为模型药物,研究了β-CD/SA水凝胶作为药物载体对BSA的负载及释放性能,结果表明:在模拟胃液中的累计释放量较小(21.5%),且释放速率较慢;在模拟肠液中的累计释放量为70.2%,具有良好的pH敏感控制释放性能。     

PVC-b-PEG共聚物的合成及其改性PVC微滤膜

采用聚乙二醇单甲醚和4,4’-偶氮双(4-氰基戊酸)反应合成制备了含偶氮基团的聚乙二醇大分子引发剂(Azo MPEG),由Azo MPEG引发氯乙烯聚合制备了聚氯乙烯-b-聚乙二醇(PVC-b-PEG)共聚物,用凝胶渗透色谱、核磁共振和红外光谱等表征了共聚物的结构,并研究PVC-b-PEG共聚物添加量对PVC微滤膜水接触角、形貌、拉伸力学性能、水和牛血清蛋白(BSA)溶液通量的影响。结果表明,PVC-b-PEG共聚物的亲水性优于PVC;随着PVC-b-PEG共聚物含量的增加,PVC微滤膜的孔隙结构连通性提高,水通量明显增强,水通量保持率较高。抗污性能测试表明,随着PVC-b-PEG共聚物含量的增加,微滤膜的BSA溶液通量明显增加,经过再生后的通量恢复率也保持较高水平,表明PVC-b-PEG共聚物能有效提高PVC微滤膜的抗污性能。     

AMA-m-P(AA-co-NVP)共聚物水凝胶的合成与溶胀性能研究

合成了金刚烷胺改性丙烯酸-N-乙烯基吡咯烷酮(AMA-m-P(AA-co-NVP))共聚物水凝胶,通过改变原料配比可有效调控水凝胶的溶胀率.金刚烷胺(AMA)的比例越大,反应中和效率越低.随着反应物中AMA/AA和NVP/AA比例的升高,共聚物水凝胶的溶胀率逐渐增大.产物AMA-m-P(AA-co-NVP)聚合物水凝胶...     

Poly(HEMA-co-AAm)水凝胶对氯霉素的缓释作用

采用本体共聚法制备poly(HEMA-co-AAm)（甲基丙烯酸羟乙酯与丙烯酰胺共聚物）水凝胶,采用恒温释放方法研究了poly(HEMA-co-AAm)水凝胶对氯霉素的缓释作用。结果表明,随水凝胶中AAm组分的含量增大,水凝胶对氯霉素的吸收量增大,氯霉素的释放速率也相应增大;随缓释介质的pH值下降,氯霉素的释放速率增大;在初始释放阶段,氯霉素的迁移速率随水凝胶中AAm组分的含量增大而增大,但随后并无明显影响。     

Polyacrylamide‐grafted carboxymethyl cellulose: Smart pH‐sensitive hydrogel for protein concentration

A novel application, utilizing polyacrylamide‐g‐carboxymethyl cellulose (CMC‐g‐PAM) in concentrating dilute solutions of Bovine serum albumin (BSA), was investigated. The grafting reaction parameters were investigated and the hydrogel smartness was verified. FT‐IR proved that the grafting reaction occurred between the hydroxyl group located in anhydroglucose C₂ position of CMC and the π‐bond of PAM and SEM confirmed a changed morphology to a fibrillar structure. The pH sensitivity was proved; as the grafted polymer attained its maximum swelling at pH 7.2 while the minimum swelling was observed under acidic conditions (pH 1‐3). The rate of water uptake in the grafted polymer hydrogel was higher than that of the homopolymer hydrogel and the swelling behaviors of both hydrogels obeyed second‐order kinetics. The tested hydrogel showed a high potency towards concentrating BSA solutions with a concentration factor of 1 to 4.5 times and recovery of 60–90%. The concentration factor increased linearly with increasing both the polymer concentration and the process time and decreased with the increase in the protein concentration. The grafted polymer had stable efficiency in the concentration process for 20 cycles. The obtained results have recommended the employment of the prepared CMC‐g‐PAM hydrogel in the down stream protein concentration process in the industrial scale. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

The imprinting induce‐fit model of specific rebinding of macromolecularly imprinted polymer microspheres

The rebinding behavior of protein‐imprinted hydrogel is different from classical small molecularly imprinted polymer especially in protein aggregating state and interaction changeability between protein and imprinted sites. BSA‐imprinted calcium alginate‐hydroxy ethyl cellulose microspheres were prepared, and the rebinding behavior was studied. An “imprinting induce‐fit model” was proposed to describe the rebinding property of protein‐imprinted hydrogel. Three kinds of different interacting forms between protein and imprinted hydrogel were discovered by Scatchard analysis. Slogistic fit analysis of rebinding rate coefficient was carried out, and the imprinted hydrogel was found capable of promoting rebinding through induce‐fit behavior. Higher imprinting efficiency was found in microsphere samples with lower crosslinking density. Rebinding regression equation was established, and the rebinding quantity was computable with parameters including BSA aggregate concentration [P_n], dissociating rate (k₁), and single molecule rebinding rate (k₂). The experimental and calculated rebinding concentration were compared, and errors between ?9.43% and 5.59% were found. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:1847–1856, 2011     

PEG/a-环糊精准聚轮烷水凝胶与BSA相互作用的光谱学研究

聚乙二醇（PEG）与环糊精（CD）自组装形成的准聚轮烷水凝胶可作为蛋白缓释载体。在此三元体系中,PEG、CD和蛋白质之间可能存在一定的相互作用。本文以牛血清白蛋白（BSA）为模型蛋白,通过紫外-可见吸收光谱,荧光光谱,X射线粉末衍射（XRD）和NOESY谱分析等技术,研究BSA在PEG/a-CD准聚轮烷水凝胶中结构的变化。结果表明BSA对水凝胶的生成速率具有显著的影响。通过荧光光谱和同步荧光光谱分析可知,BSA在水凝胶中其三级结构发生轻微变化,致使最大荧光发射波长发生红移,而Trp和Tyr残基在水凝胶中其微环境发生了微小变化。这些变化随着BSA浓度的提高而趋于显著。对比XRD谱图发现,水凝胶在加入BSA前后,2q = 6.56°、11.54°、12.06°、20.56°、22.04°、26.04°这些衍射角位置的谱峰发生明显变化,说明BSA对PEG/a-CD准聚轮烷的晶型有一定的改变,反映了BSA与水凝胶不只是单纯的混合,而且存在形成复合物而改变蛋白质结构的可能性。2D NOESY谱图也表明BSA与PEG/a-CD准聚轮烷之间存在氢原子的相互耦合作用,证明了两者之间的相互作用。     

Properties of Aqueous Bismuth Titanate Suspensions Stabilized by Acrylic Acid/Acrylic Ester Copolymer

The properties of an aqueous Bi₄Ti₃O₁₂ suspension stabilized by an acrylic acid/acrylic ester copolymer have been investigated. The adsorption of a copolymer on Bi₄Ti₃O₁₂ surface resulted in a dramatic increase in the absolute zeta potential at pH 3–11. Coincidentally, the rheological property of the suspension was significantly improved. The adsorption quantity increased with increasing copolymer concentration at first, then decreased as the copolymer concentration was beyond 1.5 wt%. The viscosity varied in a complicated manner with copolymer concentration, due to the variations in the adsorption quantity and adsorption configuration of the copolymer molecules on Bi₄Ti₃O₁₂ particle surface. High-quality tapes were prepared through tape casting.     

Synthesis and characterization of electrically responsive poly(acrylamide)-grafted-chondroitin sulfate hydrogel for transdermal drug delivery application

Abstract

Electrically-responsive transdermal delivery systems (ETDS) were developed utilizing poly(acrylamide)-grafted-chondroitin sulfate (PAAm-g-CS) copolymer. A nitrogen environment based free radical polymerization was used to synthesize electrically responsive PAAm-g-CS copolymer. This PAAm-g-CS hydrogel was used as drug reservoir and cross-linked blend films of CS and poly(vinyl alcohol) as rate controlling membranes (RCM). The drug permeation decreased with increase in the concentration of glutaraldehyde and RCM thickness; while drug permeation was increased with increasing electric stimulus from 2 to 8?mA. Nearly, three-fold increase in flux was observed with the application of electric stimulus. The permeation study under “on–off” electric stimulus suggested that the higher drug permeation was observed under “on” condition of electric stimulus and permeation was decreased when electric stimulus was “off”. The histopathology evaluation confirmed the changes in skin structure when electrical stimulus was applied. Hence, the PAAm-g-CS hydrogel could be a resourceful material for on-demand discharge of medication.     

Preparation,characterization, and drug-release properties of PEG-DA-based copolymer hydrogel microspheres

The research was to design a carrier used in tissue engineering and drug-release system. In this article, a new dispersion polymerization system without organic solvent was described to prepare poly(ethylene glycol) diacrylate/2-hydroxyethyl methacrylate (PEG-DA/HEMA) copolymer hydrogel microspheres as carrier, which introduced chitosan (CS) as reaction medium and costabilizer, polyvinylpyrrolidone (PVP) as steric stabilizer and benzoy peroxide (BPO) as initiator. The effects of mass ratios of monomers, concentration of stabilizer and initiator on partilcle size and polydispersity index (PDI) of microspheres were investigated. Furthermore, bovine serum albumin (BSA) as protein model, the composition of copolymer, size, and polydispersity index of microspheres were employed to study the amount and released ratio of loaded BSA in this article. The results showed that hydrogel microspheres with 3.26 ± 0.24 μm in particle size and 1.03 ± 0.008 in PDI, obtained with mass ratios of PEG-DA 60/HEMA 40, 2 wt % of stabilizer content and 2 wt % of initiator content (relative to total mass of monomers), had 124.57 ± 3.14 mg/g in the amount of loaded BSA and 59.09 ± 1.43% of released ratio. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Hydrophobicities and antibacterial activities of silicone polyester/titanium dioxide composites on nylon fabrics after argon plasma treatment

To be more biocompatible, poly(N-isopropyl acrylamide) (PNIPAM) hydrogel, as a typical temperature-sensitive hydrogel, is expected to be linked with other materials of excellent biocompatibility. For this propose, poly(N-isopropyl acrylamide)-block-poly(3-O-allyl-α-D-glucose) (PNIPAM-b-POAG), a new diblock copolymer, was successfully synthesized from N-isopropyl acrylamide (NIPAM) and 3-O-allyl-1,2:5,6-di-O-isopropynylene-α-D-glucose (OAIG) via reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of cumyl dithiobenzoate (CDB). PNIPAM-b-POAG was characterized byFourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H NMR) spectroscopy, and gel permeation chromatography (GPC). The critical micelle concentration (CMC) of the copolymer was 0.045 mg/ml measured by fluorescence spectroscopy. The copolymer solution exhibited a reversible sol-gel phase transitions with the increase or decrease of temperature. An in situ gel formed rapidly after subcutaneously injecting the copolymer solution into a Sprague Dawley (SD) rat, which indicated the copolymer has a good injectable property. The in vitro release result showed that methylene blue (MB) as a model was sustainably released by the temperature-sensitive PNIPAM-b-POAG diblock copolymer at 37 °C within 120 h. The copolymer showed no apparent cytotoxicity on L929 cells by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The novel temperature-sensitive hydrogel is a promising candidate for drug delivery.     

Thermoresponsive poly (N-vinylcaprolactam)-g-galactosylated chitosan hydrogel: synthesis,characterization, and controlled release properties

Abstract

A dual (thermo- and pH-) responsive hybrid copolymer, poly(N-vinylcaprolactam) grafted galactosylated chitosan (PNVCL-g-GC) was synthesized by EDC/NHS crosslinking. PNVCL-g-GC exhibited a temperature-dependent phase change (LCST) at 32?°C in aqueous solutions. PNVCL-g-GC hydrogel scaffold was fabricated by freeze-drying, and evaluated as a delivery vehicle dependent on environmental pH and temperature. PNVCL-g-GC was characterized using ATR-FTIR, 1H-NMR, DSC, TGA, rheometry, and SEM. The swelling degree increased by the decrease both in temperature and pH. A faster BSA release was observed at 40?°C and at pH 7.2 from the cytocompatible and hemocompatible copolymer.     

Preparation and characterization of EVAL hollow fiber membrane adsorbents filled with cation exchange resins

EVAL hollow fiber membrane adsorbents filled with powder D061-type cation exchange resin were prepared through dry-wet spinning process, using hydrophilic copolymer EVAL as the fiber substrate. The microstructures of the membrane adsorbents were observed, and the pure water fluxes, BSA rejection, and static adsorption capacities of membrane adsorbents for BSA were measured. The effect of the resin-filled content on membrane performance has been discussed. The results showed that EVAL hollow fiber membrane adsorbents filled with D061-type cation exchange resins had good adsorption capacity, and the adsorption capacity increased with the quantity of the resin-filled content. The static protein adsorption capacity was 77.14 mg BSA/g membrane adsorbents when D061 resin loading content was 65% at pH 4.5.