Bharadwaj Rachayita, Roy Chandrashish, Ghosh Sourabh, Kumar Sachin
Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India.
Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India.
Biointerphases. 2025 May 1;20(3). doi: 10.1116/6.0004504.
Protein interactions on graphene-based materials (GBMs) are predominantly governed by interphase surface properties such as surface chemistry and roughness; however, the critical role of surface potential (SP) in modulating these interactions remains largely unexplored. In this work, we investigated a model study highlighting how two distinct GBMs [graphene oxide (GO) and reduced graphene oxide (RGO)] with different SP regulate protein interactions, spanning from macroscopic adsorption to molecular-level conformational changes. Through thermal reduction, hydrophilic GO was transformed into hydrophobic RGO, generating distinct SP of +120 mV for GO and +60 mV for RGO. This modulation in SP created a platform for differential protein interactions. The influence of SP on protein interactions was evident when fibronectin (FN) was introduced onto GO and RGO surfaces. Quartz crystal microbalance with dissipation and fluorescence microscopy revealed that the distinct SP of GO and RGO surfaces significantly affected FN adsorption. On the RGO substrate, which exhibited a lower SP, FN adsorption was ∼3 times greater than on the GO substrate. In contrast, FN on the GO adopted elongated fibrillar structures, driven by strong polar, hydrophilic, and electrostatic interactions at the molecular scale, regulating its conformation upon adsorption. Molecular docking simulations further supported these findings, indicating a stronger and more stable interaction between FN and RGO (binding energy C-score: -3.87, RMSD: 0.01 Å) than between FN and GO (C-score: -2.24, RMSD: 0.42 Å). Overall, this study underscores the pivotal role of SP of GBMs in modulating protein adsorption, binding stability, and conformational organization, providing key insights into the rational design of GBM biomaterials with tailored biointerface properties.
基于石墨烯的材料（GBMs）上的蛋白质相互作用主要受相间表面性质（如表面化学和粗糙度）的支配；然而，表面电位（SP）在调节这些相互作用中的关键作用在很大程度上仍未得到探索。在这项工作中，我们进行了一项模型研究，突出了具有不同表面电位的两种不同的GBMs [氧化石墨烯（GO）和还原氧化石墨烯（RGO）] 如何调节蛋白质相互作用，范围从宏观吸附到分子水平的构象变化。通过热还原，亲水性的GO转变为疏水性的RGO，产生了GO为 +120 mV、RGO为 +60 mV的不同表面电位。表面电位的这种调节为差异蛋白质相互作用创造了一个平台。当将纤连蛋白（FN）引入GO和RGO表面时，表面电位对蛋白质相互作用的影响很明显。具有耗散功能的石英晶体微天平及荧光显微镜显示，GO和RGO表面不同的表面电位显著影响FN的吸附。在表面电位较低的RGO基底上，FN的吸附量比在GO基底上大3倍左右。相反，GO上的FN由于分子尺度上强烈的极性、亲水性和静电相互作用而呈现出细长的纤维状结构，在吸附时调节其构象。分子对接模拟进一步支持了这些发现，表明FN与RGO之间的相互作用（结合能C分数：-3.87，均方根偏差：0.01 Å）比FN与GO之间的相互作用（C分数：-2.24，均方根偏差：0.42 Å）更强且更稳定。总体而言，这项研究强调了GBMs的表面电位在调节蛋白质吸附、结合稳定性和构象组织方面的关键作用，为合理设计具有定制生物界面特性的GBM生物材料提供了关键见解。
