Nanomechanical properties of hybrid coatings for bone tissue engineering

Bone tissue engineering has emerged as a promising alternative approach in the treatment of bone injuries and defects arising from malformation, osteoporosis, and tumours. In this approach, a temporary scaffold possessing mechanical properties resembling those of natural bone is needed to serve as a substrate enhancing cell adhesion and growth, and a physical support to guide the formation of the new bone. In this regard, the scaffold should be biocompatible, biodegradable, malleable and mechanically strong. Herein, we investigate the mechanical properties of three coatings of different chemical compositions onto silanized glass substrates; a hybrid material consisting of methacryloxypropyl trimethoxysilane and zirconium propoxide, a type of a hybrid organic-inorganic material of the above containing also 50 mol% 2-(dimethylamino)ethyl methacrylate (DMAEMA) moieties and a pure organic material, based on PDMAEMA. This study investigates the variations in the measured hardness and reduced modulus values, wear resistance and plastic behaviour before and after samples' submersion in cell culture medium. Through this analysis we aim to explain how hybrid materials behave under applied stresses (pile-up formations), how water uptake changes this behaviour, and estimate how these materials will react while interaction with cells in tissue engineering applications. Finally, we report on the pre-osteoblastic cell adhesion and proliferation on three-dimensional structures of the hybrid materials within the first hour and up to 7 days in culture. It was evident that hybrid structure, consisting of 50 mol% organic-inorganic material, reveals good mechanical behaviour, wear resistance and cell adhesion and proliferation, suggesting a possible candidate in bone tissue engineering.