Biomineralization on chemically synthesized collagen containing immobilized poly-γ-glutamic acid

Abstract

Chemically synthesized collagen with a triple helix structure similar to that of natural collagen is attractive as a safe biomaterial. Hybrids of chemically synthesized collagen and apatite are proposed for novel bone substitutes. However their apatite-forming ability in simulated body fluid is still quite low. We examined acceleration of apatite formation on collagen by immobilized poly-γ-glutamic acid (PGA), which has excellent apatite-forming ability. Apatite was formed within 3 days when collagen was treated with PGA solutions containing an appropriate amount of CaCl 2 . A mixture of apatite and calcite was formed at high CaCl 2 concentration. The present results indicate the possibility of preparing hybrid materials, with tailored mechanical and biological properties, based on chemically synthesized collagen.

Poly(γ-Glutamic Acid) as an Exogenous Promoter of Chondrogenic Differentiation of Human Mesenchymal Stem/Stromal Cells

“…18,21 The use of g-PGA for bone and nervous system regeneration has already been reported. 20,26 However, g-PGA potential for cartilage regeneration is far from being explored. Chang et al developed g-PGA-graft-chondroitin sulfate-blend-poly(e-caprolactone) scaffolds that were shown to support rat articular chondrocyte culture for 4 weeks.…”

“…Its application in the biomedical field has been growing, as observed by its use in biological adhesives, chelating agents for imaging techniques, vaccines, drug/gene delivery systems, and TE-scaffolds, particularly for bone and the nervous system. [18][19][20][21] In the case of bone, g-PGA has been combined with collagen (Col) in the form of g-PGA/Col sponges. Thus, g-PGA modification was shown to increase calcium deposits and apatite formation.…”

“…Thus, g-PGA modification was shown to increase calcium deposits and apatite formation. 20 In addition, both L-and D-glutamate are essential for bone mineralization, which justifies the interest in this polymer for bone regeneration. [22][23][24][25] For nerve tissue regeneration, g-PGA scaffolds were shown to favor the differentiation of induced pluripotent stem cells into neuronlineage cells.…”

Design of Injectable Poly(γ-glutamic acid)/Chondroitin Sulfate Hydrogels with Mineralization Ability

“…In addition to appropriate mechanical properties, spontaneous biomineralization is an indispensable property for hydrogels used in bone tissue engineering. − Previous studies reported that PGA-based hydrogels exhibited an excellent apatite-forming ability in simulated body fluid (SBF), because abundant −COOH of PGA are effective for heterogeneous apatite nucleation. − For instance, Ohtsuki and Miyazaki et al studied biomineralization behaviors of PGA-based hydrogels prepared by covalent cross-linking based on N -hydroxysuccinimide and 1-ethyl-3-(3-(dimethylamino)­propyl)-carbodiimide. Upon soaking in simulated body fluid (SBF), apatite was observed on the surface of PGA-based hydrogels.…”

Bioactive Co-Cr alloy for biomedical applications prepared by surface modification using self-assembled monolayers and poly-γ-glutamic acid

“…In addition, our group recently demonstrated that crosslinked poly-γ-glutamic acid (γ-PGA) can be used to induce bone-like apatite layers in SBF [22][23][24] . Taken together, these findings suggest that the immobilization of γ-PGA onto a Co-Cr alloy constructed from SAMs could be used to increase the bioactivity of the alloy.…”