Department of Chemistry, Amity University Kolkata, Major Arterial Road, Action Area II, Kadampukur Village, Rajarhat, Newtown, West Bengal, 700135, India.
Department of Physics, Jadavpur University, Kolkata, West Bengal, 700032, India.
Colloids Surf B Biointerfaces. 2020 Apr;188:110803. doi: 10.1016/j.colsurfb.2020.110803. Epub 2020 Jan 15.
Low Molecular Weight (LMWG) gelators are small molecules that form supramolecular self-assembly involving physical forces and are highly biocompatible. However, fragility of these physical gels restricts their applicability where gels of higher mechanical strength are required. Herein, we have developed two different types of 2-D carbon nanomaterials viz. graphene oxide (GO) and carbon nanosheet (CNS) embedded sodium deoxycholate (NaDC) hydrogels. XRD, scanning electron microscopy (SEM), rheology and CD studies suggest significant modification of morphological, mechanical, viscoelastic and optical properties of the nanocomposite gels which is ascribed to the presence of the 2D nanotemplates and participation of different surface functionalities of GO and CNS in the gelation process. The overall shear resistance of both the nanocomposite hydrogels upto a shear rate of 300 shears/s and above reveals tremendously improved mechanical stability with respect to the pure gels. The increased shear strength of the GO/NaDC and CNS/NaDC hydrogels is attributed to their 3-4 times broader and longer ribbon like structures in comparison to the fibrous structure of pure gels. The intact ribbon like morphology and greater entanglement impart 10 folds greater viscosity to GO-NaDC hydrogels as compared to better elasticity of CNS-NaDC hydrogels possessing broken ribbon edges. Most interestingly both GO and CNS influence the optical activity of the gels and presence of GO results in inversion of optical activity. The GO-NaDC gels are also found to demonstrate antibacterial activity against E. coli, and S. aureus. Thus, these extraordinarily modified mechanically strong gels have enhanced potential for use in tissue engineering, enantioselective and sustained drug delivery, topical antibiotics and other biomedical applications.
低分子量（LMWG）凝胶剂是形成涉及物理力的超分子自组装的小分子，具有高度的生物相容性。然而，这些物理凝胶的脆性限制了它们在需要更高机械强度的凝胶的应用。在这里，我们开发了两种不同类型的二维碳纳米材料，即氧化石墨烯（GO）和碳纳米片（CNS）嵌入的脱氧胆酸钠（NaDC）水凝胶。XRD、扫描电子显微镜（SEM）、流变学和 CD 研究表明，纳米复合材料凝胶的形态、机械、粘弹性和光学性质发生了显著变化，这归因于 2D 纳米模板的存在以及 GO 和 CNS 的不同表面官能团参与凝胶化过程。两种纳米复合水凝胶的整体剪切阻力高达 300 剪切/秒及以上，与纯凝胶相比，机械稳定性大大提高。GO/NaDC 和 CNS/NaDC 水凝胶的剪切强度增加归因于其 3-4 倍更宽更长的带状结构，与纯凝胶的纤维状结构相比。完整的带状形态和更大的缠结赋予 GO-NaDC 水凝胶 10 倍的更高粘度，而具有破碎带状边缘的 CNS-NaDC 水凝胶则具有更好的弹性。有趣的是，GO 和 CNS 都影响凝胶的光学活性，并且 GO 的存在导致光学活性的反转。GO-NaDC 凝胶也被发现对大肠杆菌和金黄色葡萄球菌具有抗菌活性。因此，这些经过特殊改性的机械强度高的凝胶具有增强的潜力，可用于组织工程、对映选择性和持续药物输送、局部抗生素和其他生物医学应用。
