Adhesive Prebiotic Chemistry Inspired Coatings for Bone Contacting Applications

New and improved bone-contacting medical devices are required to provide excellent bioactivity at the biointerface. Here, we have used coatings based on prebiotic chemistry inspired polymerization of aminomalonitrile (AMN) in combination with comonomers 3,4-di- and 3,4,5-trihydroxybenzaldehyde (DHBA and THBA). The comonomers were incorporated into the AMN coatings to enhance polymerization kinetics, adhesive properties, metal binding efficacy, and human mesenchymal stem cell (hMSC) response. Incorporation of DHBA and THBA as separate comonomers enhanced the polymerization kinetics compared to that of AMN polymerization alone, with 30 mol % THBA (30T) resulting in a 6-fold increase in thickness over 24 h. Furthermore, the adhesion of AMN coatings to silicon was enhanced when copolymerized with the HBA monomers, where the interfacial adhesion of the 30T coating was increased 20-fold. The ability of the coatings to incorporate zinc ions was investigated, and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that incorporating 30T increased the binding efficiency 4-fold compared to that of AMN alone. The attachment, proliferation, and morphology of human mesenchymal stem cells (hMSC) on these coatings was investigated and reported. Finally, the utility of the coatings as osteogenic support matrices via the induced osteogenic differentiation of hMSCs is reported. The AMN and 30T coatings resulted in the greatest efficiency of osteogenic differentiation, as measured by intracellular ALP activity and mineralization. Incorporation of zinc had a stimulatory effect on hMSC proliferation with 30T coatings, while enhanced mineralization was observed with the zinc functionalized AMN and 30T coatings. This study highlights the potential of prebiotic chemistry inspired coatings in biomedical applications.