Biomimetic Tunable Electroactive Surfaces for Bone-on-Chip

Conjugated polymers such as polypyrrole (PPy) are interesting materials for bio-applications due to their low redox potentials (1&lt;V), biocompatibility, and can be operated in any aqueous electrolytes, including full blood and cell culture medium. Previously, we demonstrated that chondrocyte-derived plasma membrane nanofragments (PMNFs) initiate bone formation <i>in vivo</i> and can be used to fabricate biomimetic bone microenvironments <i>in vitro</i>. Using coupling chemistry, we now covalently immobilised the PMNFs onto the PPy surface. By alternating the redox potential, we can dynamically control the presentation of the attached PMNFs. This influences the biological activity and thereby the mineralisation of bone on the surface. The different redox states resulted in different morphologies of the bone minerals on the surface, which in turned showed to influence the viability of bone marrow cells. Such biomimetic tunable electroactive surfaces are a valuable tool for dynamically altering the biofunctionality of the surface to study cell-cell and cell-matrix interactions or develop a more optimized artificial stem cell niche.