Extraction and characterization of bovine collagen Type V and its effects on cell behaviors

Collagen Type V(Col.V)plays an essential role in cell behaviors and has attracted increasing attention in recent years.Highpurity Col.V is needed for evaluating its biological properties.In this research,the enzymatic hydrolysis process was combined with ultrafiltration to purify Col.V from the bovine cornea.The purity of Col.V was determined to be above 90%by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)and high-performance liquid chromatography methods.The effect of Col.V on cell behaviors was evaluated.The circular dichroism spectroscopy results demonstrated that the extracted Col.V exhibited a complete triple helix structure.SDS-PAGE suggested that the molecular weight of Col.V was 440 kDa.The self-assembly experiment revealed that the proportion of Col.V in the collagen mixture can affect the Col.I fiber diameter.The cell culture results implied that Col.V can inhibit fibroblasts(L929)proliferation.The L929 showed maximum mobility when the addition of Col.V was 30%.Thus,Col.V has the effect of inhibiting L929 proliferation and promoting migration.The high-purity Col.V provides useful information for further understanding its biological implications.

Biological evaluations of decellularized extracellular matrix collagen microparticles prepared based on plant enzymes and aqueous two-phase method

For patients with extensive full-thickness burns who do not have sufficient autologous splitthickness skin for skin grafts,the application of biological skin substitutes may be considered.The aim of this study was to find an optimal new type method for the production of a biovital skin substitute based on acellular dermal matrix(ADM)and preclinical evaluations.In this work,25 methods of ADM production were assessed.The proposed methods are based on the use of the following enzymes:papain,Carica papaya lipase(CPL),and purification using a polymer/salt aqueous two-phase system.The obtained ADM samples were characterized via scanning electron microscopy(SEM),porosity measurement and water vapor transmission test.Results showed that the collagen bundles of ADM microparticles were intact and orderly.Through differential scanning calorimetry(DSC),thermo gravimetric analysis(TGA)and biocompatibility tests,the results indicated that the proportion of papain and CPL was the same and 5 h processing time are the optimum conditions for ADM preparation and the material showed good biocompatibility.Our results suggested that the potential of developing this kind of decellularization process to manufacture ADM scaffolds for clinical application.

Sensitive direct-conversion X-ray detectors formed by ZnO nanowire field emitters andβ-Ga_(2)O_(3)photoconductor targets with an electron bombardment induced photoconductivity mechanism

Sensitive X-ray detection is needed in diverse areas motivated by a common desire to reduce radiation dose.Cold cathode X-ray detectors operating with a photoelectron multiplication mechanism called electron bombardment induced photoconductivity(EBIPC)have emerged as promising candidates for low-dose X-ray detection.Herein,the cold cathode detectors formed by ZnO nanowire field emitters andβ-Ga_(2)O_(3)photoconductor targets were proposed for sensitive direct-conversion X-ray detection.The charge carrier transport mechanism of EBIPC effect in X-ray detectors was investigated to achieve a high internal gain(2.9×10^(2))and high detection sensitivity(3.0×10^(3)μCGy^(−1)_(air)cm^(−2))for a 6 keV X-ray at the electric field of 22.5 Vμm−1.Furthermore,the proposed X-ray detectors showed the features of fast response time(40 ms),long-term stability(0.6%for 1 h),and low detection limit(0.28 mGy_(air)s^(−1)),suggesting that the direct-conversion cold cathode X-ray detectors are ideal candidates for low-energy X-ray detecting and imaging applications.