Department of Materials Engineering, Indian Institute of Science Bangalore, Bangalore 560012, India.
Department of Mechanical Engineering, Indian Institute of Science Bangalore, Bangalore 560012, India.
ACS Appl Mater Interfaces. 2021 Jun 2;13(21):24505-24523. doi: 10.1021/acsami.1c05394. Epub 2021 May 24.
Polyacrylamide-based hydrogels are widely used as potential candidates for cartilage replacement. However, their bioapplicability is sternly hampered due to their limited mechanical strength and puncture resistance. In the present work, the strength of polyacrylamide (PAM) hydrogels was increased using titanium oxide (TiO) and carbon nanotubes (CNTs) separately and a combination of TiO with CNTs in a PAM matrix, which was interlinked by the bonding between nanoparticles and polymers with the deployment of density functional theory (DFT) approach. The synergistic effect and strong interfacial bonding of TiO and CNT nanoparticles with PAM are attributed to high compressive strength, elastic modulus (>0.43 and 2.340 MPa, respectively), and puncture resistance (estimated using the needle insertion test) for the PAM-TiO-CNT hydrogel. The PAM-TiO-CNT composite hydrogel revealed a significant self-healing phenomenon along with a sign toward the bioactivity and cytocompatibility by forming the apatite crystals in simulated body fluid as well as showing a cell viability of ∼99%, respectively. Furthermore, for new insights on interfacial bonding and structural and electronic features involved in the hydrogels, DFT was used. The PAM-TiO-CNT composite model, constructed by two interfaces (PAM-TiO and PAM-CNT), was stabilized by H-bonding and van der Waals-type interactions. Employing the NCI plot, HOMO-LUMO gap, and natural population analysis tools, the PAM-TiO-CNT composite has been found to be most stable. Therefore, the prepared polyacrylamide hydrogels in combination with the TiO and CNT can be a remarkable nanocomposite hydrogel for cartilage repair applications.
聚丙烯酰胺水凝胶被广泛用作软骨替代物的潜在候选物。然而，由于其机械强度和耐刺穿性有限，其生物适用性受到严重阻碍。在本工作中，分别使用氧化钛 (TiO) 和碳纳米管 (CNT) 以及 TiO 和 CNT 在聚丙烯酰胺基质中的组合来提高聚丙烯酰胺 (PAM) 水凝胶的强度，通过纳米颗粒与聚合物之间的键合来交联，采用密度泛函理论 (DFT) 方法。TiO 和 CNT 纳米颗粒与 PAM 的协同效应和强界面键合归因于高抗压强度、弹性模量（分别为>0.43 和 2.340 MPa）和耐刺穿性（通过针插入试验估计）PAM-TiO-CNT 水凝胶。PAM-TiO-CNT 复合水凝胶具有显著的自修复现象，并且在模拟体液中形成磷灰石晶体以及表现出约 99%的细胞活力，表现出生物活性和细胞相容性。此外，为了深入了解水凝胶中的界面键合以及结构和电子特性，使用了 DFT。通过氢键和范德华型相互作用稳定的 PAM-TiO-CNT 复合模型由两个界面（PAM-TiO 和 PAM-CNT）构建。通过 NCI 图、HOMO-LUMO 间隙和自然布居分析工具，发现 PAM-TiO-CNT 复合模型最稳定。因此，与 TiO 和 CNT 结合的制备聚丙烯酰胺水凝胶可以成为用于软骨修复应用的卓越纳米复合水凝胶。
