Invitro and invivo analysis of the biocompatibility of two novel and injectable calcium phosphate cements.

Dan Meng,Limin Dong,Qingsong Jiang,Yafei Yuan

doi:10.1093/rb/rby027

Abstract

Calcium phosphate cements (CPCs) have been widely used as bone graft substitutes for many years. The aim of this study was to evaluate the biocompatibility of two novel injectable, bioactive cements: β-tricalcium phosphate (β-TCP)/CPC and chitosan microsphere/CPC in vitro and in vivo. This was accomplished by culturing mouse pre-osteoblastic cells (MC3T3-E1) on discs and pastes of CPCs. Cell growth, adhesion, proliferation and differentiation were assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide and alkaline phosphatase assays as well as by scanning electron microscopy and fluorescence. The effect of CPC paste curing was also evaluated. Implantation of two materials into the muscle tissue of rabbits was also studied and evaluated by histological analysis. Cell analysis indicated good biocompatibility in vitro. The fluorescence assay suggested that the cured material discs had no obvious effect on cell growth, while the curing process did. Histological examination showed no inflammatory cell infiltration into soft tissue. These data suggest that β-TCP/CPC and chitosan microsphere/CPC composites may be promising injectable material for bone tissue engineering.

Highlights

Calcium phosphate cements (CPCs) have been widely studied and applied clinically as bone graft substitutes for dental, craniofacial and orthopedic applications [1,2,3]
B- Tricalcium phosphate (TCP)/CPC and chitosan microsphere/ CPC are two novel self-setting bioactive cements produced by Institute of Nuclear and New Energy Technology, Tsinghua University (Beijing, China). b-tricalcium phosphate (b-TCP) or chitosan microspheres increase CPC cell compatibility in vitro and bio-functionalization in vivo
The control a-TCP/CPC powder was composed of aTCP [a-Ca3(PO4)2], calcium dihydrogen phosphate monohydrate [Ca(H2PO4)2H2O] and calcium carbonate (CaCO3) in a 10: 3.5: 1.5 molar ratio

Summary

Introduction

Calcium phosphate cements (CPCs) have been widely studied and applied clinically as bone graft substitutes for dental, craniofacial and orthopedic applications [1,2,3]. CPCs are self-setting, have moderate compressive strength even at loading sites, are highly biocompatible, and have osteo-conductive properties. These properties are conducive to growth and differentiation of osteoblasts and osteoprogenitor cells [4]. CPCs do have disadvantages including poor absorption and low strength, which undermine the clinical therapeutic efficacy of CPCs. b- Tricalcium phosphate (TCP)/CPC and chitosan microsphere/ CPC are two novel self-setting bioactive cements produced by Institute of Nuclear and New Energy Technology, Tsinghua University (Beijing, China). Our previous studies demonstrated improvements in degradation and osteo-conductive properties in vivo by porous chitosan microsphere/CPC [8]

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