Collagen Type I Biomaterials as Scaffolds for Bone Tissue Engineering

Collagen type I is the main organic constituent of the bone extracellular matrix and has been used for decades as scaffolding material in bone tissue engineering approaches when autografts are not feasible. Polymeric collagen can be easily isolated from various animal sources and can be processed in a great number of ways to manufacture biomaterials in the form of sponges, particles, or hydrogels, among others, for different applications. Despite its great biocompatibility and osteoconductivity, collagen type I also has some drawbacks, such as its high biodegradability, low mechanical strength, and lack of osteoinductive activity. Therefore, many attempts have been made to improve the collagen type I-based implants for bone tissue engineering. This review aims to summarize the current status of collagen type I as a biomaterial for bone tissue engineering, as well as to highlight some of the main efforts that have been made recently towards designing and producing collagen implants to improve bone regeneration.Part of the work presented here has been supported by the Spanish Network on Cell Therapy (Red TerCel; RD16/0011/0022), the Spanish Ministry of Economy, Industry and Compet itiveness (MINECO; BIO2015-66266), the VI National R&D&I Plan 2008–2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions, the Instituto de Salud Carlos III, and European Regional Development Fund, the Regional Government of Andalusia (PAIDI group BIO-217), a national doctoral scholarship given by the Administrative Department of Science, Technology, and Innovation (COLCIENCIAS), and the Research Department (DIEB) of the Universidad Nacional de Colombia.Ye