Physical and Chemical Characterization of Biomineralized Collagen with Different Microstructures

Abstract

Mineralized collagen is the basic unit in hierarchically organized natural bone with different structures. Polyacrylic acid (PAA) and periodic fluid shear stress (FSS) are the most common chemical and physical means to induce intrafibrillar mineralization. In the present study, non-mineralized collagen, extrafibrillar mineralized (EM) collagen, intrafibrillar mineralized (IM) collagen, and hierarchical intrafibrillar mineralized (HIM) collagen induced by PAA and FSS were prepared, respectively. The physical and chemical properties of these mineralized collagens with different microstructures were systematically investigated afterwards. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that mineralized collagen with different microstructures was prepared successfully. The pore density of the mineralized collagen scaffold is higher under the action of periodic FSS. Fourier transform infrared spectroscopy (FTIR) analysis showed the formation of the hydroxyapatite (HA) crystal. A significant improvement in the pore density, hydrophilicity, enzymatic stability, and thermal stability of the mineralized collagen indicated that the IM collagen under the action of periodic FSS was beneficial for maintaining collagen activity. HIM collagen fibers, which are prepared under the co-action of periodic FSS and sodium tripolyphosphate (TPP), may pave the way for new bone substitute material applications.

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

“…The different I-EMC samples exhibit similar infrared spectral patterns. Firstly, the absorption peaks corresponding to the triple helical structure of collagen are present, indicating that the triple helical structure of collagen is well-preserved after mineralization ( Du et al, 2022 ). In the biomimetic mineralization process, calcium phosphate ions first aggregate to form ACP, which then deposits within the collagen fibers and eventually transforms into poorly crystalline hydroxyapatite and hydroxyapatite crystals.…”

“…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 ). The preparation of I-EMC involves three essential components: Type-I collagen, minerals, and non-collagen analogs (NCP) ( Oosterlaken et al, 2021 ).…”

Mineralized Collagen Fiber-based Dental Implant: Novel Perspectives

“…The P and Ca elements throughout the mineralization process changed the calcium-deficient HA and apatite crystals into amorphous calcium phosphate (ACPs). 18 The scissor-like bend vibration of water molecule H 2 O causes the band at 1637 cm –1 . Similar to this, the Si–O and Si–O–Si linkage vibrations’ asymmetric stretching can be seen in the band at 1097 and 802 cm –1 , respectively.…”

Functionalization of biomimetic mineralized collagen for bone tissue engineering

“…Recent studies have demonstrated that periodic fluid shear stress (FSS) can replace polyacrylic acid (PAA) and induce highly-arranged IMC and HIMC in the presence of TPP [ 72 , 73 ]. Moreover, periodic FSS has been shown to improve the hydrophilicity, enzymatic stability, and crystal conversion of mineralized collagen [ 74 ]. In addition, other substances such as polyamide dendritics [ 75 , 76 ], sodium alginate [ 77 ], chitosan [ 21 , 53 ], sodium citrate [ 78 ], succinic acid [ 79 ], alkaline phosphatase (ALP) [ 80 ], and osteopontin (OPN) [ 81 ] have also been found to regulate the process of biomimetic mineralization in vitro .…”

“…Variations in preparation methods, material sources, and processing parameters can lead to changes in the nanostructure of MC [ 74 ]. These changes, in turn, affect the mechanical properties, degradability, and bone-inducing ability of MC both in vitro and in vivo .…”