Intrafibrillar mineralization of type I collagen with calcium carbonate and strontium carbonate induced by polyelectrolyte-cation complexes

Yizhou Zhang; Yiru Wang; Zhengyi Zhang; Zhe Wang; Changyu Shao; Matthias Hannig; Zihuai Zhou; Baiping Fu

doi:10.1039/d3na00705g

Intrafibrillar mineralization of type I collagen with calcium carbonate and strontium carbonate induced by polyelectrolyte-cation complexes

Nanoscale Adv. 2023 Nov 29;6(2):467-480. doi: 10.1039/d3na00705g. eCollection 2024 Jan 16.

Authors

Yizhou Zhang¹, Yiru Wang¹, Zhengyi Zhang¹, Zhe Wang¹, Changyu Shao¹, Matthias Hannig², Zihuai Zhou¹, Baiping Fu¹

Affiliations

¹ Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Engineering Research Center of Oral Biomaterials and Devices of Zhejiang Province Hangzhou 310000 fbp@zju.edu.cn 11818406@zju.edu.cn.
² Clinic of Operative Dentistry, Periodontology and Preventive Dentistry, Saarland University 66421 Homburg Germany.

Abstract

Calcium carbonate (CaCO₃), possessing excellent biocompatibility, bioactivity, osteoconductivity and superior biodegradability, may serve as an alternative to hydroxyapatite (HAp), the natural inorganic component of bone and dentin. Intrafibrillar mineralization of collagen with CaCO₃ was achieved through the polymer-induced liquid precursor (PILP) process for at least 2 days. This study aims to propose a novel pathway for rapid intrafibrillar mineralization with CaCO₃ by sequential application of the carbonate-bicarbonate buffer and polyaspartic acid (pAsp)-Ca suspension. Fourier transform infrared (FTIR) spectroscopy, zeta potential measurements, atomic force microscopy/Kelvin probe force microscopy (AFM/KPFM), and three-dimensional stochastic optical reconstruction microscopy (3D STORM) demonstrated that the carbonate-bicarbonate buffer significantly decreased the surface potential of collagen and CO₃^2-/HCO₃^- ions could attach to collagen fibrils via hydrogen bonds. The electropositive pAsp-Ca complexes and free Ca²⁺ ions are attracted to and interact with CO₃^2-/HCO₃^- ions through electrostatic attractions to form amorphous calcium carbonate that crystallizes gradually. Moreover, like CaCO₃, strontium carbonate (SrCO₃) can deposit inside the collagen fibrils through this pathway. The CaCO₃-mineralized collagen gels exhibited better biocompatibility and cell proliferation ability than SrCO₃. This study provides a feasible strategy for rapid collagen mineralization with CaCO₃ and SrCO₃, as well as elucidating the tissue engineering of CaCO₃-based biomineralized materials.