人工髓核材料-聚乙烯醇水凝胶的溶胀性能研究

利用冷冻-解冻法制得聚乙烯醇(PVA)水凝胶弹性体,研究了其用于人工髓核材料的溶胀特性,以及聚乙烯醇浓度、溶胀温度、溶胀体系的pH值对其溶胀性能的影响,采用扫描电镜对其微观形貌进行了观察,并对其溶胀动力学进行了探讨。结果表明,聚乙烯醇水凝胶是一种多孔网状结构,网络孔径大小与水凝胶中聚乙烯醇的含量有关;增加聚乙烯醇的浓度,提高溶胀温度以及溶胀体系的pH值,其平衡溶胀率减小;通过溶胀动力学方程对其溶胀过程进行了描述,水凝胶中聚乙烯醇的含量,试样尺寸以及溶胀体系的pH值,是溶胀速率快慢的重要影响因素。     

沉淀法原位复合聚乙烯醇(PVA)/羟基磷灰石(HA)水凝胶的结构与性能研究

研究了制备聚乙烯醇(PVA)，羟基磷灰石(HA)复合水凝胶的沉淀法原位复合技术，对该法制备的复合水凝胶的力学强度、结晶性能和微观形貌进行了分析，并与物理共混法加以比较。结果表明，沉淀法原位复合技术可在PVA水凝胶基体中合成得到粒度细，分散好的晶相HA陶瓷微粒，复合后水凝胶的结晶度和拉伸强度比之基体试样均有大幅度提高。     

直接心辅装置CRG/PVA复合水凝胶隔离层的制备与性能研究

基于气动肌肉的直接心辅装置近年来成为研究热点,针对该装置,提出一种水凝胶生物材料隔离层,用于避免气动肌肉与心脏直接接触,减小摩擦力与排异反应。首先选取聚乙烯醇(PVA)作为水凝胶隔离层3D打印的前驱体材料,并进行PVA水凝胶的制备;然后针对水凝胶固化时间长无法应用于3D打印的问题,加入卡拉胶(CRG)进行优化,并进行力学以及溶胀性能探究;最后将3D成型技术运用到隔离层的成型过程,并对水凝胶隔离层的摩擦磨损性能进行研究。结果表明,CRG/PVA复合水凝胶材料拉伸断裂应变及应力分别为280%、0.84 MPa,力学性能良好;CRG不仅能缩短水凝胶固化时间,且其含量从1%增加至5%,水凝胶溶胀度提高到3.70;水凝胶隔离层在120个工作周期后表面仅轻微损伤,进一步验证该结构能改善心脏摩擦环境。     

γ射线辐照交联PVA水凝胶关节软骨修复材料 的结构与性能研究

目的 研究制备工艺对γ射线辐照交联PVA水凝胶关节软骨修复材料的结构与摩擦学性能的影响,为其在关节软骨损伤修复提供理论基础。方法 采用冷冻解冻和辐照交联相结合的方法制备聚乙烯醇(PVA)水凝胶,研究其微观形貌、含水量及与自然软骨配副的摩擦学性能。结果 (1)微观结构的观察表明,制备的PVA水凝胶具有三维多孔网络结构,辐照交联使得网络结构更加致密和完善;(2) 水凝胶的含水量随着辐照剂量和PVA浓度的增加而减小;(3) 在往复式销-盘摩擦磨损试验机上研究本水凝胶材料与自然关节软骨配副时的摩擦学性能,结果表明,摩擦的起始阶段,双相润滑机制其主导作用,载荷主要由水凝胶中的液体相所承担,摩擦系数较小,随着载荷作用时间的延长,固体相所承受载荷的比例相对增高,摩擦系数渐渐增大且趋于稳定,润滑机制转为边界润滑。摩擦系数随着辐照剂量和PVA浓度的增加而减小。     

PVP/PVA水凝胶力学性能的分子动力学模拟

目的从分子微观角度研究复合材料的力学性能及其单组份间发生相互作用的本质。方法用分子动力学(molecular dynamics,MD)方法模拟研究聚乙烯毗咯烷酮(PVP)、聚乙烯醇(PVA)以及其混合体系PVP/PVA的力学性能、径向分布函数等性质。结果 PVP与PVA有机结合之后的混合体系PVP/PVA较纯PVP体系力学性能有了明显的提高,且复合材料的力学性能不受温度的影响;混合体系两单组份间的相互作用主要是通过PVP分子单元中的氧原子与PVA中的羟基形成较强的氢键作用。结论 MD分析结果从分子层面揭示PVP/PVA复合水凝胶组份间相互作用机理,其力学性能较单组份PVP水凝胶有较大提高且不受温度影响;为临床制备水凝胶假体组织及其理化性能研究提供了一种可靠的理论研究方法。     

人工髓核材料-聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性研究*

目的评估人工髓核材料聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性。方法根据ISO10993-1标准,采用细胞毒性试验(琼脂扩散法)、皮内刺激试验、Ame's致突变试验、微核试验和体内植入(360天)试验对聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性进行评估。结果聚乙烯醇水凝胶/聚乙烯纤维复合物的细胞毒性评分小于Ⅰ级,细胞生长无明显抑制现象,对皮内无刺激作用,Ames致突变试验为阴性,微核出现率为3.48‰,无致突变反应。体内植入符合植入材料生物学评价要求。结论聚乙烯醇水凝胶/聚乙烯纤维复合物具有良好的生物安全性,是一种无毒、对皮肤及肌肉、椎间隙无刺激作用的生物医用材料,在动物体内不引起排异反应,可应用于临床。     

掺锶复合PVA/生物活性玻璃水凝胶的制备及其体外软骨修复性能研究

目的研究以聚乙烯醇(PVA)、生物活性玻璃(BG)及氯化锶为主要原料,制备的PVA水凝胶、PVA/生物活性玻璃水凝胶、掺锶复合PVA/生物活性玻璃水凝胶的可降解性能、离子释放性能和促软骨修复性能。方法PVA溶液与BG溶胶凝胶溶液在加热搅拌下生成PB水凝胶,PVA溶液与Sr-BG溶胶凝胶溶液加热搅拌生成PBSr水凝胶,将PB和PB-Sr水凝胶浸泡于磷酸盐缓冲液(PBS)中,研究其体外降解性能、离子释放性能和结构变化。在水凝胶上培养软骨细胞,经细胞增殖能力实验和细胞荧光染色观察细胞增殖情况。结果 PB和PB-Sr水凝胶在PBS溶液中逐渐降解,28 d后PB水凝胶降解率为25%,PB-Sr水凝胶降解率为16%,水凝胶表面均有羟基磷灰石形成。细胞实验结果显示培养7 d后PB-Sr水凝胶的OD值为0.76±0.04,PB水凝胶的OD值为0.52±0.02,均显著高于对照组,PVA水凝胶的OD值0.45±0.04,差异具有统计学意义(0.05)。结论该掺锶复合PVA/生物活性玻璃水凝胶具有良好的降解性能和离子释放性能,能有效促进软骨细胞增殖。     

PVA /HA复合水凝胶力学性能分析及有限元模拟

目的通过实验与有限元模拟对羟基磷灰石(HA)改变聚乙烯醇/羟基磷灰石(PVA/HA)复合水凝胶的力学性能本质及其承载特性进行研究。方法在UMT试验机上进行PVA/HA复合水凝胶的压缩及应力松弛实验。通过模拟与实验结果相结合,研究PVA/HA复合水凝胶的承载特性及HA对其性能的影响。结果随着HA含量的增加,PVA/HA复合水凝胶的压缩模量先增大后减小,而渗透系数先减小后增大;HA含量为3%的PVA/HA复合水凝胶压缩模量最大、渗透系数最小,分别为1.25 MPa和1.59×10-3 mm4.N-1.s-1。PVA/HA复合水凝胶的液体承载比例随着施载时间的增加呈现先增加后减小的非线性变化,加入HA的PVA/HA复合水凝胶的液体承载比例明显增加。应力松弛速率随着HA含量增加呈先上升后下降趋势,下压相同位移HA,含量为3%时,PVA/HA复合水凝胶所能分散的应力更多。结论 PVA/HA复合水凝胶内部的承载特性影响着其力学性能,HA含量为3%时的PVA/HA复合水凝胶力学性能最优,更接近于天然关节软骨的力学性能。     

羟基磷灰石/聚乙烯醇水凝胶的制备与生物活性评价

背景:先前的研究表明,羟基磷灰石/聚乙烯醇水凝胶复合水凝胶(hydroxyapatite/polyvinylalcoholhydrogel,HA/PVA-H)具有较好的机械性能和耐摩擦磨损性能,这说明HA/PVA-H复合材料具有早期承载能力和较好的生物活性。那么HA/PVA-H复合材料能否通过羟基磷灰石粒子与周围骨组织较快地形成活性结合呢?目的:制备羟基磷灰石/聚乙烯醇水凝胶,并对其进行生物学评价。方法:将Ca(OH)2研磨过筛后,配制成一定浓度的悬浮分散液;加入质量分数15%的PVA水溶液中,添加二甲亚砜,最后按Ca/P比1.67:1加入H3PO4的乙醇溶液,制备HA/PVA-H。对试样进行体外模拟体液培养实验,测试浸泡前后SBF浸泡液的变化,并利用扫描电镜、FTIR、XRD对材料的结构进行了表征和分析。结果与结论:扫描电镜观察可知羟基磷灰石/聚乙烯醇水凝胶表面有结晶体形成,经XRD分析确认为弱结晶的羟基磷灰石晶体;浸泡之后浸泡液的pH值与Ca、P离子浓度下降,同时FTIR结果显示试样中的PO43-特征峰得到增强,且有CO32-的特征峰形成。结果提示,羟基磷灰石/聚乙烯醇水凝胶复合材料具有较好的生物活性。     

聚乙烯醇水凝胶及其复合物的研究与在人工软骨替代材料上的应用

聚乙烯醇水凝胶是一种具有良好生物相容性和力学性能的高弹性材料。本文介绍了聚乙烯醇水凝胶的成型方法，复合改性技术的研究进展，着重对聚乙烯醇水凝胶作为替代材料在关节软骨损伤修复中的研究现状和存在问题进行了综述，并概述了其应用前景和发展方向。     

Synthesis and Characterization of High-Transparent Poly(vinyl alcohol)/Poly(vinyl pyrrolidone)(PVA/PVP) Hydrogels

In this paper, transparent poly(vinyl alcohol)/poly(vinyl pyrrolidone)(PVA/PVP) hydrogels were prepared by using the solvent of dimethyl sulfoxide(DMSO) aqueous solution and the method of freeze/thawing. The effect of PVP interaction, mechanical property and transparence of PVA/PVP hydrogel was investigated and evaluated by FT-IR analysis, mechanical test machine and UV spectrophotometer. The results showed that when the content of PVP was 8% in the DMSO aqueous solution, the highest transparence of PVA/PVP hydrogel was obtained, with excellent tensile strength values higher than 3.5 MPa. Therefore, the PVA/PVP hydrogel composite has a potential to be used as the transparent core of a novel artificial cornea.     

人工髓核材料-聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性研究*

目的评估人工髓核材料聚乙烯醇水凝胶／聚乙烯纤维复合物的生物相容性。方法根据ISO10993-1标准，采用细胞毒性试验（琼脂扩散法）、皮内刺激试验、Ame’s致突变试验、微核试验和体内植入（360天）试验对聚乙烯醇水凝胶／聚乙烯纤维复合物的生物相容性进行评估。结果聚乙烯醇水凝胶／聚乙烯纤维复合物的细胞毒性评分小于Ⅰ级，细胞生长无明显抑制现象，对皮内无刺激作用，Ames致突变试验为阴性，微核出现率为3．48‰，无致突变反应。体内植入符合植入材料生物学评价要求。结论聚乙烯醇水凝胶／聚乙烯纤维复合物具有良好的生物安全性，是一种无毒、对皮肤及肌肉、椎间隙无刺激作用的生物医用材料，在动物体内不引起排异反应，可应用于临床。     

Wound healing properties of PVA/starch/chitosan hydrogel membranes with nano Zinc oxide as antibacterial wound dressing material

In this work, hydrogel membranes were developed based on poly vinyl alcohol (PVA), starch (St), and chitosan (Cs) hydrogels with nano Zinc oxide (nZnO). PVA/St/Cs/nZnO hydrogel membranes were prepared by freezing-thawing cycles, and the aqueous PVA/St solutions were prepared by dissolving PVA in distilled water. After the dissolution of PVA, starch was mixed, and the mixture was stirred. Then, chitosan powder was added into acetic acid, and the mixture was stirred to form a chitosan solution. Subsequently, Cs, St and PVA solutions were blended together to form a homogeneous PVA/St/Cs ternary blend solution. Measurement of Equilibrium Swelling Ratio (ESR), Water Vapor Transmission Test (WVTR), mechanical properties, scanning electron microscopy (SEM), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide] assay, antibacterial studies, in vivo wound healing effect and histopathology of the hydrogel membranes were then performed. The examination revealed that the hydrogel membranes were more effective as a wound dressing in the early stages of wound healing and that the gel could be used in topic applications requiring a large spectrum of antibacterial activity; namely, as a bandage for wound dressing.     

Optimizing the tensile properties of polyvinyl alcohol hydrogel for the construction of a bioprosthetic heart valve stent

Although bioprosthetic heart valves offer the benefits of a natural opening and closing, better hemodynamics, and avoidance of life-long anticoagulant therapy, they nevertheless tend to fail in 10-15 years from tears and calcification. Several authors, including the present ones, have identified the rigid stent as a factor contributing to these failures. The ultimate solution is an artificial heart valve that has mechanical properties that allow it to move in conformity with the aortic root during the cardiac cycle, has superior hemodynamics, is nonthrombogenic, will last more than 20 years, and mitigates the need for anticoagulants. We have identified a polymer, polyvinyl alcohol (PVA) hydrogel, that has mechanical properties similar to soft tissue. The purpose of this research is to match the tensile properties of PVA to the porcine aortic root and to fabricate a stent prototype for a bioprosthetic heart valve with the use of the PVA hydrogel. Specimens of 15% w/w PVA were prepared by processing through 1-6 cycles of freezing (-20 degrees C) at 0.2 degrees C/min freeze rate and thawing (+20 degrees C) at different thawing rates (0.2 degrees C/min and 1 degrees C/min), for different holding times (1 and 6 h) at -20 degrees C. Subsequently tensile tests and stress-relaxation tests were conducted on the specimens. The different holding times at -20 degrees C demonstrated no difference in the result. The slower thawing rate improved the tensile properties but did not produce significant changes on the stress-relaxation properties. The nonlinear stress-strain curve for the PVA after the fourth freeze-thaw cycle matched the porcine aortic root within the physiological pressure range. The stress-relaxation curve for PVA also approximated the shape of the aortic root. The complex geometry of an artificial heart valve stent was successfully injection molded. These results, in combination with other preliminary findings for biocompatibility and fatigue behavior, suggest that PVA hydrogel is a promising biomaterial for implants, catheters, and artificial skin.     

Functional compressive mechanics of a PVA/PVP nucleus pulposus replacement

Emerging techniques as an alternative to the current treatments of lower back pain include nucleus replacement by an artificial material, which aims to relieve pain and restore the normal spinal motion. The compressive mechanical behavior of the PVA/PVP hydrogel nucleus implant was assessed in the present study. PVA/PVP hydrogels were made with various PVP concentrations. The hydrogels were loaded statically under unconfined and confined conditions. Hydrogels were tested dynamically up to 10 million cycles for a compression fatigue. Also, hydrogel nucleus implants with a line-to-line fit, were implanted in the human cadaveric intervertebral discs (IVD) to determine the compressional behavior of the implanted discs. Hydrogel samples exhibited typical non-linear response under both unconfined and confined compressions. Properties of the confinement ring dictated the observed response. Hydrogel moduli and polymer content were not different pre- and post-fatigues. Slight geometrical changes (mostly recoverable) were observed post-fatigue. In cadavers, hydrogels restored the compressive stiffness of the denucleated disc when compared with equivalent condition of the IVD. The results of this study demonstrate that PVA/PVP hydrogels may be viable as nucleus pulposus implants. Further studies under complex loading conditions are warranted to better assess its potential as a replacement to the degenerated nucleus pulposus.     

新型人工髓核植入对腰椎稳定性影响的生物力学研究

目的: 评价一种新型果胶/聚乙烯醇复合水凝胶人工髓核的生物力学性能, 为其临床应用提供科学依据。方法: 采用6具新鲜人体标本的 L4/5脊柱功能单元进行生物力学实验, 在轴向压缩、前屈后伸和左右侧弯等运动工况下, 观察正常椎间盘、髓核摘除以及新型人工髓核CoPP植入三种状态下活动度(ROM)、中性区(NZ)的变化以及在中立位轴向加载下椎间隙高度变化。结果: 髓核摘除后, L4/5椎间屈伸、旋转、侧弯的ROM和 NZ较正常组显著增加(P<0.05), 植入CoPP人工髓核后, L4/5椎间屈伸、侧弯、旋转的 ROM和 NZ与完整椎间盘无明显差异, 除右侧弯外其他方向的ROM和 NZ较髓核摘除组明显下降　(P<0.05)。髓核摘除组在 0和500N的负荷下椎间隙高度较相同情况下正常组平均下降1.08 mm和 1.77 　mm; CoPP人工髓核植入组较相同情况下髓核摘除组分别增加1.23 mm和1.95 mm。结论: 新型果胶/聚乙烯醇复合水凝胶人工髓核植入椎间隙可维持腰椎节段正常的三维运动稳定性,恢复椎间隙高度,可望进入临床应用。