Enhanced Intrafibrillar Mineralization of Collagen Fibrils Induced by Brushlike Polymers

Biomimetic mineralization of collagen fibrils is an essential process because the mineralized collagen fibers constitute the basic building block of natural bone. To overcome the limited availability and high cost of the noncollagenous proteins (NCPs) that regulate the mineralization process of collagen, commercially available analogues were developed to replicate sequestration and templating functions of NCPs. The use of branched polymers in intrafibrillar mineralization applications has never been explored. In this work, two novel carboxyl-rich brushlike polymers, a carboxylated polyethylene glycol terpolymer (PEG-COOH) and a polyethylene glycol/poly(acrylic acid) copolymer (PEG-PAA), were synthesized and modified to mimic the sequestration function of NCPs to induce intrafibrillar mineralization of collagen fibrils. It was found that these synthetic brushlike polymers are able to induce intrafibrillar mineralization by stabilizing the amorphous calcium phosphate (ACP) nanoprecursors and subsequently fa...