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ABSTRACT: In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet-visible absorption (UV-vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ∆H, ∆G and ∆S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay.
Materials science & engineering. C, Materials for biological applications. 07/2013; 33(5):2611-9.
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ABSTRACT: Human-like collagen (HLC) was cross-linked with hyaluronic acid by genipin in different ratio. The concentrations of hyaluronic acid in the mixture were 0, 0.01%, 0.05% and 0.1%. The blood vessel tubular grafts were then fabricated by freeze-drying. Microstructure, element composite, mechanical properties, cytotoxicity grade, and biocompatibility of different vascular scaffold groups were studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), tensile test, burst pressure experiment, cytotoxicity experiment, endothelial cells planted in blood vessel scaffolds and hypodermic embedding of mice. The results showed that HLC-HA (0.05%) tubular scaffold exhibited interconnected well-distributed and porous structure and porosity of 94.38%; achieved the desirable mechanical property with stress of (1000.8 +/- 7.9) kPa and burst pressure of (1058.6 +/- 8.2) kPa, hypocytotoxicity, favourable cytocompatibility, hisocompatibility and disposition of degradation.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 05/2009; 25(4):591-8.
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ABSTRACT: With the increasing occurrence of vascular diseases and poor long-term patency rates of current small diameter vascular grafts, it becomes urgent to pursuit biomaterial as scaffold to mimic blood vessel morphologically and mechanically. In this study, novel human-like collagen (HLC, produced by recombinant E. coli)/chitosan tubular scaffolds were fabricated by cross-linking and freeze-drying process. The scaffolds were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and tensile test, respectively. Human venous fibroblasts were expanded and seeded onto the scaffolds in the density of 1 x 10(5) cells/cm(2). After a 15-day culture under static conditions, the cell-polymer constructs were observed using SEM, confocal laser scanning microscopy (CLSM), histological examination, and biochemical assays for cell proliferation and extracellular matrix production (collagen and glycosaminoglycans). Furthermore, the scaffolds were implanted into rabbits' livers to evaluate their biocompatibility. The results indicated that HLC/chitosan tubular scaffolds (1) exhibited interconnected porous structure; (2) achieved the desirable levels of pliability (elastic up to 30% strain) and stress of 300 +/- 16 kPa; (3) were capable of enhancing cell adhesion and proliferation and ECM secretion; (4) showed superior biocompatibility. This study suggested the feasibility of HLC/chitosan composite as a promising candidate scaffold for blood vessel tissue engineering.
Journal of Biomedical Materials Research Part A 02/2009; 89(3):829-40. · 2.63 Impact Factor
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ABSTRACT: Fed-batch cultures of recombinant Escherichia coli BL21 for producing human-like collagen were performed at different specific growth rates (0.1 approximately 0.25 h(-1)) before induction and at a constant value of 0.05 h(-1) after induction by the method of pseudo-exponential feeding. Although the final biomass (around 69 g l(-1)) was almost the same in all fed-batch cultures, the highest product concentration (13.6 g l(-1)) was achieved at the specific growth rate of 0.15 h(-1) and the lowest (9.6 g l(-1)) at 0.25 h(-1). The mean productivity of human-like collagen was the highest at 0.15 h(-1) (0.57 g l(-1)h(-1)) and the lowest at 0.1 h(-1) (0.35 g l(-1 )h(-1)). In the phase before induction, the cell yield coefficient (Y(X/S)) decreased when the specific growth rate increased, while the formation of acetic acid increased upto 2.5 g l(-1) at 0.25 h(-1). The mean product yield coefficient (Y(P/S)) also decreased with specific growth rate increasing. The respiration quotient (RQ) increased slightly with specific growth rate increasing before induction, and the mean value of RQ was around 72%. The optimum growth rate for human-like collagen production was 0.15 approximately 0.2 h(-1).
Biotechnology Letters 07/2005; 27(12):865-70. · 1.68 Impact Factor
