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.