A novel strategy to enhance interfacial adhesion in fiber-reinforced calcium phosphate cement

Abstract

Calcium phosphate cements (CPCs) are extensively used as synthetic bone grafts, but their poor toughness limits their use to nonload-bearing applications. Reinforcement through introduction of fibers and yarns has been evaluated in various studies but always resulted in a decrease in elastic modulus or bending strength when compared to the CPC matrix. The aim of the present work was to improve the interfacial adhesion between fibers and matrix to obtain tougher biocompatible fiberreinforced calcium phosphate cements (FRCPCs). This was done by adding a polymer solution to the matrix, with chemical affinity to the reinforcing chitosan fibers, namely trimethyl chitosan (TMC). The improved wettability and chemical affinity of the chitosan fibers with the TMC in the liquid phase led to an enhancement of the interfacial adhesion. This resulted in an increase of the work of fracture (several hundred-fold increase), while the elastic modulus and bending strength were maintained similar to the materials without additives. Additionally the TMC-modified CPCs showed suitable biocompatibility with an osteoblastic cell line. Graphical Abstract (for review) Highlights HIGHLIGHTS• Calcium phosphate cements were reinforced with chitosan fibers and soluble chitosan• The chemical affinity of fibers and matrix improved interfacial adhesion• Mechanical reinforcement was achieved thanks to a good fiber-matrix adhesion• Fiber-reinforced cements were significantly tougher than non-reinforced analogues • The modified cement matrix supported osteoblast proliferation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 -2 - AbstractCalcium phosphate cements (CPCs) are extensively used as synthetic bone grafts, but their poor toughness limits their use to non-load-bearing applications. Reinforcement through introduction of fibers and yarns has been evaluated in various studies but always resulted in a decrease in elastic modulus or bending strength when compared to the CPC matrix. The aim of the present work was to improve the interfacial adhesion between fibers and matrix to obtain tougher biocompatible fiber-reinforced calcium phosphate cements (FRCPCs). This was done by adding a polymer solution to the matrix, with chemical affinity to the reinforcing chitosan fibers, namely trimethyl chitosan (TMC). The improved wettability and chemical affinity of the chitosan fibers with the TMC in the liquid phase led to an enhancement of the interfacial adhesion. This resulted in an increase of the work of fracture (several hundred-fold increase), while the elastic modulus and bending strength were maintained similar to the materials without additives. Additionally the TMC-modified CPCs showed suitable biocompatibility with an osteoblastic cell line.

In vitro apatite formation of calcium phosphate composite synthesized from fish bone

“…Recently, it was revealed that the crystalline phase composition of sintered fish bone is similar to mineral phase of natural bone which is composed of HA at about 93 wt% and about 7 wt% of b-tricalcium phosphate (b-TCP). [11][12][13] The considerable research effort has been done to synthesize the novel CPs-polymer cement composites. The recently published review summarizes the literature on the production of HA from fish bones and discusses their potential applications in biomedical field.…”

“…Incorporation of polymeric additives into cement liquid phase is the suitable way to fabricate a new CPC with the sufficient mechanical properties. [11][12][13] The considerable research effort has been done to synthesize the novel CPs-polymer cement composites. According to unique properties of natural polymer (eg, chitosan, alginate, starch etc.)…”

Reinforcement of calcium phosphate cement using alkaline-treated silk fibroin

“…However, the amide C=O bond and amide C-N bond shift to 1,537 cm -1 and 1,648 cm -1 , respectively, for tSF, implying a random form of SF chains. 30 These results indicate that the secondary structure of SF changes after treatment with the calcium hydroxide solution. Compared with SF, the tSF appears to have more random chains rather than β-sheets.…”

Bioceramics and bone healing

“…Different issues remain to be improved in CPC, such as mechanical properties – to more closely mimic those of natural bone. Modification with soluble polymers 30 and reinforcement with polymer and ceramic fibres 31 , 32 represent a step forward in this direction. Another aspect that has been the subject of extensive research is the adjustment of porosity as a strategy to enhance biological performance.…”