Preparation, Characterization and In Vitro Biological Evaluation of a Novel Pearl Powder/Poly-Amino Acid Composite as a Potential Substitute for Bone Repair and Reconstruction.

Yanan Wu,Zhengwen Ding,Mizhi Ji,Yonggang Yan,Haohao Ren

doi:10.3390/polym11050831

Abstract

Many studies about fabricating organic-inorganic composite materials have been carried out in order to mimic the natural structure of bone. Pearl, which has a special block-and-mortar hierarchical structure, is a superior bone repair material with high osteogenic activity, but it shows few applications in the clinical bone repair and reconstruction because of its brittle and uneasily shaped properties. In this work, pearl powder (P)/poly (amino acid) (PAA) composites were successfully prepared by a method of in situ melting polycondensation to combine the high osteogenic activity of the pearl and the pliability of the PAA. The mechanical properties, in vitro bioactivity and biocompatibility as well as osteogenic activity of the composites were investigated. The results showed that P/PAA composites have both good mechanical properties and bioactivity. The compressive strength, bending strength and tensile strength of the composites reached a maximum of 161 MPa, 50 MPa and 42 MPa, respectively; in addition, apatite particles successfully deposited on the composites surface after immersion in simulated body fluid (SBF) for 7 days indicated that P/PAA composites showed an enhanced mineralization capacity and bioactivity due to incorporation of pearl powder and PAA. The cell culture results revealed that higher cell proliferation and better adhesion morphology of mouse bone marrow mesenchymal stem cells (MSCs) appeared on the composite surface. Moreover, cells growing on the surface of the composites exhibited higher alkaline phosphatase (ALP) activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes (COL 1, RunX2, OCN, and OPN) than cells grown on PAA surface. The P/PAA composites exhibited both superior mechanical properties to the pearl powder, higher bioactivity and osteogenic capability compared with those of PAA.

Highlights

Bone, a critical tissue responsible for supporting the human body, has been inevitably damaged for a long time of use, and disease attack leads to the study of bone repair materials [1]
The P/poly-amino acid (PAA) composites were fabricated by a method of in situ melting polycondensation
The results revealed that higher cell proliferation and better adhesion morphology appeared on the P/PAA composites

Summary

Introduction

A critical tissue responsible for supporting the human body, has been inevitably damaged for a long time of use, and disease attack leads to the study of bone repair materials [1]. Among these bone repair materials, the substitution of load-bearing bone segments is considered to be one of the important and challenging parts in orthopedic surgery [2]. The calcium phosphate ceramics-based polymer composites have been widely studied and used for the bone repair materials mainly based on the fact that the human bone is composed of apatite and collagen, a kind of polymer mainly composed of amino acids. Qian et al prepared a new nano-hydroxyapatite/polyamide 66/glass fiber composite with good biomechanical properties and biocompatibility but no effect on matrix mineralization and osteogenic differentiation of mesenchymal stem cells [13]

Results

Discussion

Conclusion