含硅水凝胶角膜接触镜材料的脱水行为

采用重量法研究了γ–（甲基丙烯酰氧）丙基三甲氧基硅烷（KH570）与甲基丙烯酸–2–羟基乙酯（HEMA）及N–乙烯基吡咯烷酮（NVP）共聚物水凝胶角膜接触镜材料的脱水行为。结果表明,含硅水凝胶接触镜材料的脱水机理可采用两种极限情况下的幂律模型来描述,即脱水动力学级数n=0.5和n=1;当n=1时,水凝胶的失水率（Mt/M0c）与时间t成正比,为蒸发阶段;随后的脱水阶段中n=0.5,水凝胶的Mt/M0c与时间t1/2成正比,为扩散阶段;含硅水凝胶接触镜材料的脱水速率随单体NVP和 KH570含量增大而降低,随脱水温度的升高而提高,随盐离子浓度的增加而降低。     

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。     

水凝胶角膜接触镜材料的研究进展

分析了角膜接触镜对所需高分子材料性能的要求;介绍了角膜接触镜材料的研发历程,特别介绍了仿生材料水凝胶、互穿网络水凝胶、NVP-CS-HEMA半互穿网络水凝胶等新型角膜接触材料及其性能;在材料制备方面,重点讨论了化学引发和光引发技术;最后对本领域的发展进行了展望。     

表面接枝MPC硅水凝胶的制备及生物学评价

采用常压辉光放电等离子体处理硅水凝胶材料表面并引发2-甲基丙烯酰氧乙基磷酰胆碱（MPC）在其表面接枝聚合。硅水凝胶膜接枝MPC后,水接触角由103°下降到53°,表明接枝MPC后硅水凝胶材料具有良好的亲水性。采用四唑盐比色实验（MTT法）和直接接触细胞培养法评价材料对鼠成纤维细胞（1929）的细胞毒性,结果显示,与硅水凝胶一起培养的细胞生长状况良好,呈现较高的细胞相对增殖率,细胞毒性为1级,血小板粘附实验显示接枝MPC的硅水凝胶表面吸附的血小板数量明显减少。     

水凝胶接触镜材料的溶胀行为与脱水行为

INTRODUCTION Most contact lens are made by organic hydrogel, and thepermeability of hydrogel to oxygen is critical because comea requiresoxygen for metabolism of its principal nutrient.     

硅凝胶制备中水玻璃的应用

本文介绍了硅凝胶制备中水玻璃的应用情况。     

硅水凝胶隐形眼镜材料的合成与性能研究

以甲基丙烯酸羟乙酯（HEMA）、N-乙烯基毗咯烷酮（NVP）和γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH-570）为单体,以偶氮二异丁腈（AIBN）为引发剂,通过本体聚合反应合成新型硅水凝胶角膜接触镜.考察了各单体配比、反应温度等对聚合的影响.结果表明,当反应温度为90℃,反应时间为2h,V（HEMA）：V（NVP）：V（KH-570） =8∶ 1∶1时,合成的隐形眼镜透氧量（DK/t）达到64.0×10-9（cm3O2·cm）/（cm2·s·mmHg）,含水量38％,透光率95.5％以上.     

用掺杂有机颜料的硅凝胶制备玻璃表面装饰膜

采用溶胶－凝胶法掺杂酞菁绿,汉莎黄制备装饰膜,玻璃表面镀膜利用旋转法。用椭圆偏光仪测量了膜厚,用色度计测量了装饰膜的颜色,结果表明有机颜料的掺杂量和热处理的温度对装饰膜的主波长和色纯度有关重要影响。     

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。     

PVA/SA复合水凝胶溶胀及无机三氮离子传递性能

以聚乙烯醇（PVA）、海藻酸钠（SA）、活性炭、硼酸和氯化钙为原料,制备复合水凝胶微生物固定化载体材料,分析了离子在水凝胶膜中的扩散渗透机理,采用池膜法测定水凝胶的NH⁺₄、NO^-₂、NO^-₃离子扩散性能。结果表明,在PVA、SA、活性炭含量分别为4％、2.0%及0.2%时,以5%的氯化钙的饱和硼酸溶液为交联剂,交联时间15 min的条件下制备的固定化脱氮微生物载体传递性能最佳。复合水凝胶平衡溶胀度、扩散系数随PVA浓度升高而增大,随SA浓度升高溶胀度降低,离子扩散系数起初随SA浓度升高而升高,随后出现拐点。3种无机氮离子在水凝胶中的传递速率依次为NH⁺₄>NO^-₂>NO^-₃,遵从离子有效截面积小,传递速率大的规律。改变水凝胶制备条件、原料配比对NO^-₂、NH⁺₄的渗透系数影响较大,而对NO^-₃影响较小。     

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.     

丙烯酰胺在水凝胶角膜接触镜材料制备中的应用研究

对丙烯酰胺(AM)在水凝胶角膜接触镜材料制备中的应用进行了探讨,确定了AM/甲基丙烯酸β-羟乙酯(HEMA)交联共聚水凝胶角膜接触镜材料适宜的制备工艺,即:采用本体聚合法,以过氧化苯甲酰(BPO)作引发剂,其质量分数为0.2%(基于单体混合物质量),反应温度为70℃左右,反应时间为24 h。在饱和溶解度以下,AM可与HEMA以任意摩尔比共聚,所得聚合物的透光率、饱和含水率和机械强度均能满足水凝胶角膜接触镜材料相关要求。     

Synthesis and characterization of polyamphoteric hydrogel membrane based on chitosan

Polyamphoteric hydrogel membranes were synthesized by graft copolymerization of N‐isopropylacrylamide (NIPAm) and 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) onto chitosan (CS). The incorporation of poly(NIPAm) (PNIPAm) and poly(AMPS) (PAMPS) into CS was confirmed by FTIR spectroscopy. The swelling behavior of membranes as a function of pH, temperature, and ionic strength was studied. Permeability of solutes through these membranes was investigated at different temperatures. The results showed the dual sensitivity of membranes toward pH and temperature. The formation of the polyelectrolyte complex between CS and PAMPS showed influence on the lower critical solution temperature of PNIPAm. The permeabilities of solutes through these membranes were strongly dependent on the size of solutes, solution temperature, and hydrophilicity of the membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1454–1461, 2004     

Determination of the oxygen transmissibility and permeability of hydrogel contact lenses

To test the validity of the method of stacked hydrogel contact lenses to obtain the oxygen permeability and transmissibility coefficients of the lenses, the coefficients of one low hydration (38% water) and two high hydration (55 and 58% water) hydrogel contact lenses stacked one to five on an oxygen electrode were determined. From the oxygen diffusion through the lenses, the current intensity in the stationary state was determined, and from this the “instrument” the oxygen transmissibility was obtained. The permeability coefficients of the lenses, corrected for edge effects, were obtained from the slope of the plot of the reciprocal of the transmissibility coefficients versus the lens thicknesses. The oxygen permeability and transmissibility coefficients of the lenses obtained neglected the boundary layers resistance between the stacked lenses and, therefore, these are not the “true” coefficients. This article compares the “apparent” oxygen permeability coefficients of the hydrogel contact lenses, obtained by others, with the “true” oxygen permeability coefficients obtained with a corrected equation that takes into account the boundary layers between the stacked lenses. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 321–327, 1999     

Activation of Piezo1 Increases Na,K-ATPase-Mediated Ion Transport in Mouse Lens

Lens ion homeostasis depends on Na,K-ATPase and NKCC1. TRPV4 and TRPV1 channels, which are mechanosensitive, play important roles in mechanisms that regulate the activity of these transporters. Here, we examined another mechanosensitive channel, piezo1, which is also expressed in the lens. The purpose of the study was to examine piezo1 function. Recognizing that activation of TRPV4 and TRPV1 causes changes in lens ion transport mechanisms, we carried out studies to determine whether piezo1 activation changes either Na,K-ATPase-mediated or NKCC1-mediated ion transport. We also examined channel function of piezo1 by measuring calcium entry. Rb uptake was measured as an index of inwardly directed potassium transport by intact mouse lenses. Intracellular calcium concentration was measured in Fura-2 loaded cells by a ratiometric imaging technique. Piezo1 immunolocalization was most evident in the lens epithelium. Potassium (Rb) uptake was increased in intact lenses as well as in cultured lens epithelium exposed to Yoda1, a piezo1 agonist. The majority of Rb uptake is Na,K-ATPase-dependent, although there also is a significant NKCC-dependent component. In the presence of ouabain, an Na,K-ATPase inhibitor, Yoda1 did not increase Rb uptake. In contrast, Yoda1 increased Rb uptake to a similar degree in the presence or absence of 1 µM bumetanide, an NKCC inhibitor. The Rb uptake response to Yoda1 was inhibited by the selective piezo1 antagonist GsMTx4, and also by the nonselective antagonists ruthenium red and gadolinium. In parallel studies, Yoda1 was observed to increase cytoplasmic calcium concentration in cells loaded with Fura-2. The calcium response to Yoda1 was abolished by gadolinium or ruthenium red. The calcium and Rb uptake responses to Yoda1 were absent in calcium-free bathing solution, consistent with calcium entry when piezo1 is activated. Taken together, these findings point to stimulation of Na,K-ATPase, but not NKCC, when piezo1 is activated. Na,K-ATPase is the principal mechanism responsible for ion and water homeostasis in the lens. The functional role of lens piezo1 is a topic for further study.     

有机硅改性共聚物水凝胶接触镜材料的合成与性能研究

以N-乙烯基吡咯烷酮(NVP)、甲基丙烯酸羟乙酯(HEMA)以及γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)为原料单体,N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,偶氮二异丁氰(AIBN)为引发剂,采用本体聚合法制备有机硅改性共聚物水凝胶接触镜材料,并研究了材料拉伸强度的影响因素。结果表明,所得材料的折光度为1．51,透光率达99%以上;有机硅的引入能显著提高材料的拉伸强度,NVP含量的增加使材料的拉伸强度下降。     

Improved protein resistance of silicone hydrogels by grafting short peptides for ophthalmological application

A simple and facile approach to impart the antifouling properties of silicone hydrogels was developed in this report. Short peptides were first tethered to silicone hydrogels through terminal amino group-induced epoxy ring-opening click reaction. The modified silicone hydrogels have improved hydrophilicity and protein adsorption resistance because of the formation of zwitterionic structure of the grafted peptides. Furthermore, glycylglycine and diglycyl glycine-modified silicone hydrogel contact lenses were fabricated. They exhibited favorable antifouling property and no damage to rabbits’ eyes after continuous wearing. The short peptide modified silicone hydrogel contact lenses have potential application in ophthalmology.