Synergistic intrafibrillar/extrafibrillar mineralization of collagen fibrils and scaffolds enhanced by introducing polyacrylamide to PILP for osteogenic differentiation

Abstract

Mineralization can help improve the mechanical properties and degradation rates of collagen scaffolds while ensuring good biocompatibility, thereby providing a suitable microenvironment for osteogenic differentiation. Intrafibrillar/extrafibrillar mineralization of collagen is promoted by polymer-induced liquid precursors (PILP). In this study, polyacrylamide (PAM) was introduced to PILP which synergistically mineralized collagen scaffold intrafibrillarly and extrafibrillarly. PAM and polyacrylic acid (PAA) can stabilize the amorphous calcium phosphate (ACP), to form a PILP of PAM and PAA/ACP. As a control, another scaffold material was formed using the conventional mineralization method, that is, soaking collagen in a simulated body fluid. Collagen mineralization was characterized using SEM and TEM. After 7 days of mineralization with PILP, intrafibrillar crystallization of collagen was significantly higher than that in the control group, and the stiffness and modulus of this scaffold material significantly increased. Cellular experiment results indicated that the PILP-mineralized collagen scaffold was biocompatible and promoted the osteogenic differentiation of MC3T3-E1 pre-osteoblasts. Biomimetic mineralization by PILP will assist the fabrication of mineralized collagen scaffold for bone repair applications.

In situ co-deposition synthesis for collagen-Astragalus polysaccharide composite with intrafibrillar mineralization as potential biomimetic-bone repair materials

“…Biomineralized collagen composite material is preferable for bone-repair due to its biomimetic microstructures and components similar to native bone tissue, as well as the excellent biocompatibility and biodegradability. The biomimetic mineralization in vitro of intrafibrillar mineralization, which is the closest to the secondary level of bone microstructures, was first achieved by the approach of PILP [ 45 , 46 ]. In this study, we synthesized a material of MCAPS, which are composite collagen fibrils mineralized by hydroxyapatite binding APS, with the characteristic microstructure of intrafibrillar mineralization by utilizing the method of co-precipitation.…”

In Situ Construction of Morphologically Different Hydroxyapatite-Mineralized Structures on a Three-Dimensional Bionic Chitin Scaffold

“…24−28 Superior osteoinductivity capacity plays a key role in facilitating tendon−bone healing by promoting the formation of new bones and cartilages. 29 Nowadays, the depositional mineralization of HAP has been widely investigated due to its ability to mimic the microstructure of the bone tissue matrix, 30 where the selection of a suitable mineralization template can increase the mineralization of HAP more efficiently. 31 The βchitin matrix is a suitable carrier to stabilize HAP crystals because of the large amount of acetyl amino groups on the surface, which can reduce ion mobility and trap ions to control the local calcium and phosphate ion concentrations around the functional groups, creating a sufficient chemical environment for HAP mineralization.…”

“…It has many unique properties including nonimmunogenicity, bioactivity, biocompatibility, osteoconductivity, and osteoinductivity. − Superior osteoinductivity capacity plays a key role in facilitating tendon–bone healing by promoting the formation of new bones and cartilages . Nowadays, the depositional mineralization of HAP has been widely investigated due to its ability to mimic the microstructure of the bone tissue matrix, where the selection of a suitable mineralization template can increase the mineralization of HAP more efficiently . The β-chitin matrix is a suitable carrier to stabilize HAP crystals because of the large amount of acetyl amino groups on the surface, which can reduce ion mobility and trap ions to control the local calcium and phosphate ion concentrations around the functional groups, creating a sufficient chemical environment for HAP mineralization. − Previous studies have demonstrated the feasibility of bionic layered or multiphase apatite scaffolds to promote tendon–bone healing in vitro and in vivo. − However, it remains a major challenge to achieve in situ mineralization of minerals with gradient structures.…”