Poly(acrylic acid)‐Assisted Intrafibrillar Mineralization of Type I Collagen: A Review

Abstract

The mineralization of type I collagen is a biological process occurring in vertebrates by which some hard tissues such as bone and dentin are constructed. Due to the extensive clinical needs for bone defect repair and remineralization of mineral-depleted dentin, biomimetic mineralization of collagen is attracting more and more interests. Synthetic analogs of noncollagenous proteins are necessary for directing the in vitro mineralization. In this paper, the function and mechanism of poly(acrylic acid) (PAA) in regulating the mineralization, especially intrafibrillar mineralization (IM) of collagen are reviewed. As two mineralization patterns (extrafibrillar and intrafibrillar) co-exist in natural hard tissues, differences between them in terms of microstructure, biodegradation, cytocompatibility, osteoinduction in vitro, and performance in vivo are systematically compared. Then the roles of PAA in biomimetic collagen IM within one-analog and two-analog systems are discussed, respectively. Moreover, mineralization of some self-mineralizable collagen matrices is described. Due to the interactions between collagen and PAA play a crucial role in the processes of collagen mineralization, some reference researches are also provided involving the collagen/PAA interactions in some other fields. Finally, this review is ended with an outlook for future potential improvements based on the collection of existing bottlenecks in this field.

Advances in osseointegration of biomimetic mineralized collagen and inorganic metal elements of natural bone for bone repair

“…The MC deposition was gradually formed. In addition, currently, PAA is the most widely used NCPs analogues, which can provide an abundant negative charge, mimic the structure and function of different NCPs and have good biocompatibility [ 46 ]. NCPs analogues also include carboxymethyl chitosan [ 47 ], poly-L-aspartic acid [ 48 , 49 ], osteopontin [ 49 ], alginate [ 50 ], amorphous calcium fluoride [ 51 ], etc.…”

A variable mineralization time and solution concentration intervene in the microstructure of biomimetic mineralized collagen and potential osteogenic microenvironment

“…The ideal mineralized collagen bone substitute material should include both EMC and IMC, with fixed volume ratios (3:1 in bone, 2:1 in dentin). However, despite scientists around the world putting in tremendous effort, this high-level biomimetic preparation method has not yet achieved a breakthrough ( Chen et al, 2023 ). Studies have demonstrated that, when employing the PILP method, the surface of IMC shows deposits of calcium phosphate particles, indicating the occurrence of extrafibrillar mineralization, i.e., I-EMC ( Hu et al, 2016 ; Du et al, 2022 ).…”