Biocompatible liquid-crystal elastomers mimic the intervertebral disc
Biocompatible liquid-crystal elastomers mimic the intervertebral disc
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DOI：
10.1016/j.jmbbm.2020.103757
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发表时间：
2020-07-01
影响因子：
3.9
通讯作者：
Frick, Carl P.
中科院分区：
文献类型：
--
作者：
Shaha, Rajib K.;Merkel, Daniel R.;Frick, Carl P.
承载软组织的分层和各向异性机械行为要求限制了传统弹性材料作为软组织材料替代品的实用性。液晶弹性体（LCE）由于其弹性体网络中介晶有序的独特组合而在这方面具有出色的潜力。在本研究中，探讨了与承载生物医学应用相关的 LCE 的机械行为。通过制造具有多域和单域配置的 LCE，研究了具有不同网络方向（即介晶排列）的 LCE。具有相同网络交联程度的多域和单域LCE表现出不同的机械行为，从高刚性和弹性性质到高阻尼能力，具体取决于相对于网络排列的负载方向。 LCE 还能够匹配椎间盘的各向异性机械行为。对 LCE 皮下植入后的体内生物反应以及暴露于体外模拟生理环境对机械行为的影响进行了其他研究。当暴露于生物医学相关条件时，LCE 的机械响应受到的影响可以忽略不计。此外，固体和多孔LCE在植入大鼠皮下时没有对周围组织产生任何不利影响。生物反应允许组织向内生长，并有助于说明它们在可植入生物设备中的用途。最后，通过制造概念验证的全椎间盘置换装置，证明了 LCE 在模拟椎间盘等生物组织的机械功能方面的实用性。
The hierarchical and anisotropic mechanical behavior requirement of load-bearing soft tissues limits the utility of conventional elastomeric materials as a replacement for soft-tissue materials. Liquid-crystal elastomers (LCEs) have the potential to excel in this regard owing to its unique combination of mesogenic order in an elastomeric network. In this study, the mechanical behavior of the LCEs relevant to load-bearing biomedical applications was explored. LCEs with different network orientations (i.e., mesogen alignments) were investigated by fabricating the LCEs with polydomain and monodomain configurations. The polydomain and monodomain LCEs with the same degree of network crosslinking demonstrated diverse mechanical behavior, ranging from highly stiff and elastic nature to high damping capacity, depending on the loading direction with respect to the network alignment. The LCEs were also capable of matching the anisotropic mechanical behavior of an intervertebral disc. Additional studies were conducted on the in vivo biological response of LCEs upon subcutaneous implantation, as well as on the effect of the exposure to an in vitro simulated physiological environment on the mechanical behavior. The LCEs' mechanical response was negligibly affected when exposed to biomedically relevant conditions. Furthermore, the solid and porous LCEs did not show any adverse effect on the surrounding tissues when implanted subcutaneously in rats. The biological response allows for tissue ingrowth and helps illustrate their utility in implantable biological devices. Finally, the utility of LCEs to mimic the mechanical function of biological tissue such as intervertebral disc was demonstrated by fabricating a proof of concept total disc replacement device.