Section on Quantitative Imaging and Tissue Sciences, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Soft Matter. 2022 Jun 15;18(23):4414-4426. doi: 10.1039/d2sm00505k.
A novel composite hydrogel was developed that shows remarkable similarities to load bearing biological tissues. The composite gel consisting of a poly(vinyl alcohol (PVA) matrix filled with poly(acrylic acid) (PAA) microgel particles exhibits osmotic and mechanical properties that are qualitatively different from regular gels. In the PVA/PAA system the swollen PAA particles "inflate" the PVA network. The swelling of the PAA is limited by the tensile stress developing in the PVA matrix. increases with increasing swelling degree, which is opposite to the decrease of the elastic pressure observed in regular gels. The maximum tensile stress maxel can be identified as a quantity that defines the load bearing ability of the composite gel. Systematic osmotic swelling pressure measurements have been made on PVA/PAA gels to determine the effects of PVA stiffness, PAA crosslink density, and Ca ion concentration on maxel. It is found that maxel increases with the stiffness of the PVA matrix, and decreases with (i) increasing crosslink density of the PAA and (ii) increasing Ca ion concentration. Small angle neutron scattering (SANS) measurements indicate only a weak interaction between the PVA and PAA gels. It is demonstrated that the osmotic swelling pressure of PVA/PAA composite gels reproduces the osmotic behavior of healthy and osteoarthritic cartilage.
一种新型复合水凝胶被开发出来，其性能与承重生物组织具有显著的相似性。该复合凝胶由聚（聚乙烯醇）（PVA）基质填充聚（丙烯酸）（PAA）微凝胶颗粒组成，具有与常规凝胶定性不同的渗透和机械性能。在 PVA/PAA 体系中，溶胀的 PAA 颗粒“膨胀”PVA 网络。PAA 的溶胀受到 PVA 基质中产生的拉伸应力的限制。随着溶胀度的增加而增加，这与在常规凝胶中观察到的弹性压力的减小相反。最大拉伸应力 maxel 可以被确定为定义复合凝胶承载能力的量。对 PVA/PAA 凝胶进行了系统的渗透膨胀压力测量，以确定 PVA 刚度、PAA 交联密度和 Ca 离子浓度对 maxel 的影响。结果发现，maxel 随 PVA 基质的刚度增加而增加，随（i）PAA 的交联密度增加而减小，（ii）随 Ca 离子浓度增加而减小。小角中子散射（SANS）测量表明 PVA 和 PAA 凝胶之间只有微弱的相互作用。证明 PVA/PAA 复合凝胶的渗透膨胀压力再现了健康和骨关节炎软骨的渗透行为。
