Biomineralization of Recombinant Peptide Scaffolds: Interplay among Chemistry, Architecture, and Mechanics

Biomineralized scaffolds are an attractive option for bone tissue engineering, being similar to native bone. However, optimization is difficult, due to the complex interplay among architecture, chemistry, and mechanics. Utilizing biomimetic nucleation, linear mineralized scaffolds were created from a collagen type I based recombinant peptide (RCP). Osteoblast mineralization was assessed, in response to changes in scaffold architecture, hydroxyapatite (HA) content, and mechanics. Changes in scaffold pore size (150-450 μm) had little effect on mRNA levels but influenced cell proliferation, achieving a balance between nutrient diffusion and surface area for cell attachment at 300 μm. Increasing the scaffold mechanical strength, from 2.9 to 5.2 kPa, enhanced the expression of osteocalcin, a late marker of mineralization. Further addition of HA, up to 20 wt %, increased osteoblast mineralization, without altering the compressive modulus. Thus, it was shown that architectural cues influence cellular proliferation, while the scaffold chemistry and mechanics independently contribute to gene expression.