Bone Tissue Regeneration by Collagen Scaffolds with Different Calcium Phosphate Coatings: Amorphous Calcium Phosphate and Low-Crystalline Apatite

Abstract

Surface-mineralized collagen sponges have attracted much attention as scaffolds for bone tissue engineering. Recently, we developed amorphous calcium phosphate (ACP) and low-crystalline apatite coating processes on collagen sponges. In the present study, we applied these coating processes to granular collagen sponges (referred to as Col) to compare the bone tissue regeneration capabilities of ACP-coated and apatite-coated Col (referred to as Col-ACP and Col-Ap, respectively) using a rat cranial bone defect model. According to micro-CT and histological analyses, Col-Ap enhanced bone tissue regeneration compared to Col, whereas Col-ACP did not. These results not only demonstrated the superior bone tissue regeneration capability of Col-Ap, but also indicated limitations of the in vitro simulated body fluid (SBF) test used in our previous study. Despite the apatite-forming ability of Col-ACP in SBF, it was ineffective in improving bone tissue regeneration in vivo, unlike Col-Ap, most likely due to the quick resorption of the ACP coating in the defect site. The present results clarified the importance of the coating stability in vivo and revealed that the low-crystalline apatite coating was more beneficial than the ACP coating in the fabrication of surface-mineralized collagen sponges for use as bone tissue engineering scaffolds.

Bioactive Scaffolds as a Promising Alternative for Enhancing Critical-Size Bone Defect Regeneration in the Craniomaxillofacial Region

“…24−26 The most frequent source of Col has been cows and pigs; however, new sources, such as fishes and marine organisms, have been recently proposed to overcome religious issues and potential transmission of pathogens. 27 For example, scaffolds made with fish Col mixed with gellan gum and bovine bone particles showed better osteoinductive properties than bovine Col membranes in CSDs in rats. 27 Col mats' mechanical properties and osteoinductivity have been enhanced by adding calcium phosphate (CaP) or apatite by in vitro mineralization.…”

Calcium Phosphate-Based Biomaterials for Bone Repair

“…ACPs constitute the initial phase of HAP and are essential components in the process of bone regeneration and bone mineralization due to their particular physical properties and structure [ 106 ]. ACPs possess superior biological properties, such as osteoconductivity and biodegradability, leading to a variety of applications including CaP bone cements, biological tissue engineering scaffolds, bone repair biomaterials, and dental implants [ 107 , 108 ]. In addition, the nano-sized clusters in the ACPs have characteristics of large specific surface areas and pH-responsive degradation, which makes them ideal drug delivery carriers for studies relating to drug loading and controlled release [ 35 ].…”

Periodontal Tissue Regeneration by Recombinant Human Collagen Peptide Granules Applied With β-Tricalcium Phosphate Fine Particles

“…Furthermore, the composite scaffold was effective in periodontal tissue reconstruction in a canine experimental periodontal defect model [25]. Combinations with collagen and other types of bioceramics, such as octacalcium phosphate or low-crystalline hydroxyapatite, also showed excellent bone or periodontal tissue forming effects [26][27][28][29].…”