Collagen‐gelatin‐genipin‐hydroxyapatite composite scaffolds colonized by human primary osteoblasts are suitable for bone tissue engineering applications: In vitro evidences

Orthopaedics and Traumatology Clinic, University Hospital of Siena, Siena, ItalyReceived 16 March 2013; revised 30 April 2013; accepted 31 May 2013Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/jbm.a.34823Abstract: The application of porous hydroxyapatite (HAp)-col-lagen as a bone tissue engineering scaffold represents a newtrend of mimicking the specific bone extracellular matrix(ECM). The use of HAp in reconstructive surgery has shownthat it is slowly invaded by host tissue. Therefore, implantcompatibility may be augmented by seeding cells beforeimplantation. Human primary osteoblasts were seeded ontoinnovative collagen-gelatin-genipin (GP)-HAp scaffoldscontaining respectively 10%, 20%, and 30% HAp. Cellularadhesion, proliferation, alkaline phosphatase (ALP) activity,osteopontin (OPN), and osteocalcin (OC) expressions wereevaluated after 3, 7, 15, and 21 days. The three types ofscaffolds showed increased cellular proliferation over time inculture (maximum at 21 days) but the highest was recordedin 10% HAp scaffolds. ALP activity was the highest in 10%HAp scaffolds in all the times of evaluation. OC and OPNresulted in higher concentration in 10% HAp scaffoldscompared to 20% and 30% HAp (maximum at 21 days).Finally, scanning electron microscopy analysis showedprogressive scaffolds adhesion and colonization from the sur-face to the inside from day 3 to day 21. In vitro attachment,proliferation, and colonization of human primary osteoblastson collagen-GP-HAp scaffolds with different percentages ofHAp (10%, 20%, and 30%) all increased over time in culture,but comparing different percentages of HAp, they seem toincrease with decreasing of HAp component. Therefore, themechanical properties (such as the stiffness due to theHAp%) coupled with a good biomimetic component(collagen) are the parameters to set up in compositescaffolds design for bone tissue engineering.