Papers by Keyword: Type I Collagen

Abstract: Self-assembly and mineralization of type I collagen (Col) with nanocrystalline apatite (nAp), by adding a solution of Ca(OH)₂ to a stirred Col-H₃PO₄ solution by fast dripping, allowed the preparation of Col/nAp fibrils with good crystallographic control of the mineral phase. In this work, in addition, we have cross-linked the mineralized fibers by using different reagents, namely glutaraldehyde (GTA), tannic acid (TA), 1-Ethyl-3-(3-dimethyl aminopropyl)-carbodiimide combined with N-Hydroxysuccinimide (EDC/NHS), and genipin (GP), aimed at producing different types of biopolymeric Col/nAp-based drug delivery scaffolds. In parallel, we have investigated two different methods to impregnate the scaffolds with molecules of the cocrystal diclofenac-metformin (DF-MET). The result, when using TA as a crosslinking reagent, shows the sequence of mineralized fibrils impregnation followed by crosslinking leads to maximum cocrystal molecule loading. The impregnated material is expected to be useful in settings with excessive and prolonged inflammation, since they affect negatively the fracture healing/bone repair processes, especially during the early stages of healing.

Abstract: Calcium sulfate/type I collagen composite pellets were prepared by a feasible route of casting method. The as-prepared composite pellets were characterized and the results showed that the collagen fibrils acted as bridges to connect the adjacent calcium sulfate grains, especially when there was a high mass loading of collagen, which effectively depressed the rapid degradation of the pellets and improved compressive strength, and the optimal strength reached 17.2 MPa with 6 mg/mL collagen solution. The MC3T3-E1 cells could be well attached and spread on the surface of the composite pellets. Moreover, it is found that the collagen be released through pellets degradation further promoted the cells proliferation.

Abstract: Type I collagen was isolated from calf skin and its assembly on PVA film induced by glutaraldehyde vapor was investigated. It was found that the collagen molecules were firstly orientationally assembled into collagen fibers under the inducement of glutaraldehyde vapor. Then the collagen fibers could be further aggregated into novel network structure in proper conditions of the induced reaction. The morphology of the assembled collagen fibers was depended on induced time and concentration of collagen. The network arrangement could be obtained after being induced for 72h when collagen concentration was 2.5mg/ml. At higher concentration of collagen (5 mg/ml), the collagen fibers with larger dimension were obtained, but the growth of fibers was almost in one direction.

Abstract: Composites based on hydroxyapatite (HA) and collagen are being used for bone engineering applications. Synthetic composites were produced by precipitating hydroxyapatite in a reaction medium containing collagen fibers. The effect of saline treatment during the procedure of fibrils extraction on the composite morphology, phases presented and in vitro stability was evaluated. The FTIR analysis showed collagen bands well preserved. By Rietveld analysis, additional peaks of sodium chloride were identified on sample made from collagen submitted to saline precipitation. Besides that, the mineral formed phase is a carbonated apatite. This step during fibrils extraction results in larger areas of collagen uncoated and higher stability in culture medium. Despite of this, a cross-linking agent will be necessary to maintain the composite in culture for longer times.

Abstract: The osteoinduction of Calcium Phosphate (CaP) had been proved and generally been investigated by in vivo implantation. However, the mechanism of the osteoinductivity was not clear and it was difficult to judge the osteoinductivity in vitro. In this study, Mouse C2C12 cell line, a kind of myoblast precursor cell, was employed to co-culture with CaP. The induction of cell differentiation by materials was tested by MTT method, fluorescence observation, especially the mRNA expression of Osteocalcin, Type I collagen and Fibronectin by RT-PCR. It was founded that C2C12 cells could be induced to expression osteocalcin when growth on the surface of the HA/TCP ceramics. At the same time, the ceramics with different composition and sintering temperature seemed to induce difference expression level of the related genes. The results proved that phase composition was one of the most important factors in the regulation of bone-related genes. This study provided a potential model to evaluate the osteoinductivity of CaP ceramics in vitro.