Cartilage‐inspired alginate LipoGels: Impact of different liposomes

Inspired by the exceptional lubricity in living systems (e.g. knee joints), a physically cross-linked hydrogel has been prepared from sodium alginate, an abundant green biopolymer derived from brown algae. Alginate hydrogels were cross-linked by divalent cations, Ca2+, and liposomes (or lipid vesicles) were embedded into the gel (Fig. 1), aiming to generate a lubricious and self-repairing material, also with the potential for therapeutic inclusion. The lubrication performance of the alginate hydrogels was evaluated with a tribometer (UMT Tribolab), and the results showed that the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) embedded alginate hydrogel exhibited excellent lubrication with a coefficient of friction (CoF) of 0.022 under water. Furthermore, valuable structural information on the polymer network mesh size ξ (Fig. 1) was obtained from a recent small angle neutron scattering (SANS) experiment at SANS2D. To complete a PhD study (in the 4th year), we propose a SANS investigation of the effect of different types of liposomes with varying headgroup charges and tail lengths/fluidity on the hydrogel structures. The results will offer structural insights into alginate hydrogels embedded with different types of liposomes, enabling a correlation with the mechanical characterisation of the hydrogels using nano-indenter and rheometer. Ultimately, this will underpin the rational design of robust hydrogels with tailored nanostructures for biomimetic lubrication.

受生命系统（如膝关节）中优异润滑性能的启发，研究人员以褐藻提取的丰富绿色生物聚合物海藻酸钠为原料，制备了一种物理交联水凝胶。海藻酸钠水凝胶通过二价阳离子Ca²+交联制备，并将脂质体（或称脂质囊泡）嵌入凝胶基质中（图1），以期获得兼具润滑性与自修复能力的材料，同时具备负载治疗性组分的潜力。采用摩擦试验机（UMT Tribolab）对海藻酸钠水凝胶的润滑性能进行了表征，结果显示，嵌入1,2-二棕榈酰-sn-甘油-3-磷酸胆碱（DPPC）的海藻酸钠水凝胶在水环境下展现出优异的润滑性能，摩擦系数（coefficient of friction, CoF）为0.022。此外，近期在SANS2D装置开展的小角中子散射（small angle neutron scattering, SANS）实验，获取了有关聚合物网络网格尺寸ξ的宝贵结构信息（图1）。为完成第四学年的博士研究，我们计划开展一项小角中子散射研究，考察不同头部基团电荷、尾链长度与流动性的脂质体对水凝胶结构的影响。该研究结果将为阐明不同脂质体嵌入的海藻酸钠水凝胶的结构机制提供见解，并可与采用纳米压痕仪、流变仪获得的水凝胶力学表征结果建立关联。最终，本研究将为合理设计具备定制化纳米结构、可用于仿生润滑的高性能水凝胶奠定坚实基础。