Mambiri Lillian Tsitsi, Guillory Riley, Depan Dilip
Chemical Engineering Department, Institute for Materials Research and Innovation, University of Louisiana at Lafayette, Lafayette, LA 70504, USA.
Polymers (Basel). 2025 Jul 23;17(15):2014. doi: 10.3390/polym17152014.
Osteoarthritis and metastatic bone cancers create pathological oxidative environments characterized by elevated reactive oxygen species (ROS). ROS impair bone regeneration by degrading the scaffold and suppressing mineralization. To address these challenges, we fabricated thermoresponsive scaffolds based on poly(N-isopropylacrylamide) (PNIPAAm) incorporating in situ-grown nanohydroxyapatite on graphene oxide nanoscrolls (nHA-GONS) using stereolithography (SLA). Three scaffold formulations were studied: pure PNIPAAm (PNP), PNIPAAm with 5 wt.% nHA-GONS (P5G), and PNIPAAm with 5 wt.% nHA-GONS reinforced with polycaprolactone (PCL) microspheres (PN5GP). Each scaffold was evaluated for (i) swelling and lower critical solution temperature (LCST) using differential scanning calorimetry (DSC); (ii) oxidative degradation assessed using Fourier-transform infrared spectroscopy (FTIR), mass loss, and antioxidant assays; and (iii) mineralization and morphology via immersion in simulated body fluid followed by microscopy. The PN5GP and P5G scaffolds demonstrated reversible swelling, sustained antioxidant activity, and enhanced calcium deposition, which enable redox stability and mineralization under oxidative environments, critical for scaffold functionality in bone repair. PNP scaffolds exhibited copper accumulation, while PN5GP suffered from accelerated mass loss driven by the PCL phase. These findings identify the P5G formulation as a promising scaffold. This study introduces a quantitative framework that enables the predictive design of oxidation-resilient scaffolds.
骨关节炎和转移性骨癌会产生以活性氧（ROS）升高为特征的病理性氧化环境。ROS通过降解支架和抑制矿化来损害骨再生。为应对这些挑战，我们使用立体光刻（SLA）技术制备了基于聚（N-异丙基丙烯酰胺）（PNIPAAm）的热响应性支架，该支架在氧化石墨烯纳米卷（nHA-GONS）上原位生长了纳米羟基磷灰石。研究了三种支架配方：纯PNIPAAm（PNP）、含有5 wt.% nHA-GONS的PNIPAAm（P5G）以及含有5 wt.% nHA-GONS并由聚己内酯（PCL）微球增强的PNIPAAm（PN5GP）。对每个支架进行了以下评估：（i）使用差示扫描量热法（DSC）测定溶胀和低临界溶液温度（LCST）；（ii）使用傅里叶变换红外光谱（FTIR）、质量损失和抗氧化剂测定评估氧化降解；（iii）通过浸入模拟体液后进行显微镜观察评估矿化和形态。PN5GP和P5G支架表现出可逆溶胀、持续的抗氧化活性以及增强的钙沉积，这使得在氧化环境下具有氧化还原稳定性和矿化能力，这对于骨修复中支架的功能至关重要。PNP支架表现出铜积累，而PN5GP则因PCL相导致质量损失加速。这些发现确定P5G配方是一种有前景的支架。本研究引入了一个定量框架，能够对抗氧化支架进行预测性设计。
