Objective To calculate the recovery rate and enrichment factor and to analyse the correlation by measuring the concentrations of platelets, leukocyte, and growth factors in platelet-rich plasma (PRP) so as to evaluate the feasibil ity and stabil ity of a set of PRP preparation. Methods The peripheral blood (40 mL) was collected from 30 volunteers accorded with the inclusion criteria, and then 4 mL PRP was prepared using the package produced by Shandong Weigao Group Medical Polymer Company Limited. Automatic hematology analyzer was used to count the concentrations of platelets and leukocyte in whole blood and PRP. The enrichment factor and recovery rate of platelets or leukocyte were calculated; the platelet and leukocyte concentrations of male and female volunteers were measured, respectively. The concentrations of platelet-derived growth factor (PDGF), transforming growth factor β (TGF-β), and vascular endothel ial growth factor (VEGF) were assayed by ELISA. Results The platelet concentrations of whole blood and PRP were (131.40 ± 29.44) × 109/L and (819.47 ± 136.32) × 109/L, respectively, showing significant difference (t=—27.020, P=0.000). The recovery rate of platelets was 60.85% ± 8.97%, and the enrichment factor was 6.40 ± 1.06. The leukocyte concentrations of whole blood and PRP were (5.57 ± 1.91) × 1012/L and (32.20 ± 10.42) × 1012/L, respectively, showing significant difference (t=—13.780, P=0.000). The recovery rate of leukocyte was 58.30% ± 19.24%, and the enrichment factor was 6.10 ± 1.93. The concentrations of platelets and leukocyte in PRP were positively correlated with the platelet concentration (r=0.652, P=0.000) and leukocyte concentration (r=0.460, P=0.011) in whole blood. The concentrations of platelet and leukocyte in PRP between male and female were not significantly different (P gt; 0.05). The concentrations of PDGF, TGF-β, and VEGF in PRP were (698.15 ± 64.48), (681.36 ± 65.90), and (1 071.55 ± 106.04) ng/ mL,which were (5.67 ± 1.18), (6.99 ± 0.61), and (5.74 ± 0.83) times higher than those in the whole blood, respectively. PDGF concentration (r=0.832, P=0.020), TGF-β concentration (r=0.835, P=0.019), and VEGF concentration (r=0.824, P=0.023) in PRP were positively correlated with platelet concentration of PRP. Conclusion PRP with high concentrations of platelets, white blood cells and growth factors can be prepared stably by this package.
Objective To prepare carboxymethylchitin and study its properties. Methods Chitin was prepared from fresh shrimp shells and then carboxymethylchitin was prepared by the methods of alkalization and etherification as well as by the purification technique. The deacetylation degree of carboxymethylchitin was determined by the doublejump potentiometric titration method; the substitution degree was determined by the element analysis method; the carboxymethyl substitution position was analyzed by the Fourier transform infrared spectroscopy apparatus and the nuclear magnetic resonance spectroscopy apparatus; the relative molecular weight and its polydispersity were determined by the gel permeation chromatography with the multiple angle laser light scattering detection; the biological properties were tested according to the GB/T 16886 biological evaluation on medical devices. Results Carboxymethylchitin could be prepared by alkalization and etherification from chitin which was prepared from fresh shrimp shells by decalcification and deproteinization. The deacetylation degree of carboxymethylchitin was 13.76% according to the doublejump potentiometric titration; the degrees of deacetylation and substitution were 14.53% and 1.239 0 respectively according to the element analysis. The IR spectrum showed that the substitutive position was N,O-substitution, and the 13C-NMR spectrum showed that substitutive position of carboxymethylchitin was mostly primary substitution of 6-OH, and according to the substitutive proportion, the substitutive turns were in the following decreasing order: 6-OH, NH2, and 3-OH. The weightaveraged and the numberaveraged molecular weights and polydispersity were 6.25×105, 5.60×105 and 1.22, respectively. The results from the biological property test showed that carboxymethylchitin was a biomaterial that was sterile, pyrogen-free, acute toxicity-free, cytotoxicity-free, intracutaneous irritationfree, skin sensitization-free and biomaterial genotoxicity-free, with no side or adverse effects on the related tissues after implantation into the human body. Conclusion Carboxymethylchitin prepared from chitin by alkalization and etherification is amacromolecule biomaterial that has a low degree of deacetylation, a high degreeof substitution, and a good biocompatibility.
Objective To prepare human acellular amniotic membrane(HAAM) and to measure its cytocompatibility and biocompatibility. Methods HAAM were preparedby chemical detergent-enzymatic extraction. Fresh human amnion was crosslinkedwith glutaradehyde, shaken in 0.5% SDS for 24 hours, and then treated with 0.25%trypsin for 4 hours. The production were freeze-drying and sterilized using ethylene oxide. Human fibroblasts were isolated from embryo and expanded in vitro. The fibroblasts were seeded in HAAM. HAAM and specimen were stained with HE and Mallory, and observed grossly, under light microscopy and scanning electron microscopy. The HAAM were implanted in the back of SD rats. Results There wereno residues of cells in the HAAM (HE, Mallory staining). One side of HAAM had reticular and porous structure, the other side had compact fibrous structure.Pore size was from 10 to 80 nm. The HAAM could be seeded with expanded fibroblasts in vitro,and fibroblasts had the potential of spread and proliferation. The SD rat in the implant test had no death, convulsions and other abnormal response. Conclusion The detergent-enzymatic extraction process can remove cellsand solvable components effectively and preserve the tissue matrix well and keep the reticular structure. The HAAM can be used as an ideal scaffold of biological membrane for tissue engineering.
Objective To develop a new kind of skin substitute, selective acellular porcine skin, to cover excised wounds in treatment of extensivedeep burns on the basis of controlled de-cell technique. Methods Partial thickness porcine skin was treated with 0.25% trypsin for 2 hours at 37℃ after crosslinked with glutaraldehyde, and then it was glued to a container with the edge embedded with glue. The skin was shaken in 0.5% SDS for 24 hours, and then washed before use. The selective acellular skin was used with micro-autografts on the dermal side to cover 2 surgically excised burn wounds in a patient. The recoveries of function and appearance were observed. Results Morphological observation showed that the treated porcine skin had an intact epithelial layer and an acellular dermis. After being used to cover burn wounds, its acellular dermis could serve as host dermal matrix, and its devitalized epithelial layer could prevent the dermis from drying. The devitalized epithelium wasfinally replaced by host epithelial cells, and the healed wounds could achieve good cosmetic and functional results. Conclusion Selective acellular porcine skin can be used as promising skin substitute to cover excised wounds.
OBJECTIVE: To review the research advance of the preparation and characteristics of small intestinal submucosa(SIS). METHODS: Recent original articles related to such aspects of small intestinal submucosa were reviewed extensively. RESULTS: Small intestinal submucosa was an easily obtained biomaterial. SIS was a bio-absorbable and degradable material. SIS had tissue specific regeneration properties. CONCLUSION: SIS is a suitable bio-derived material for tissue engineering of blood vessel, muscle tendon, urinary bladder and abdomen.
OBJECTIVE: To prepare chitosan-gelatin/hydroxyapatite (CS-Gel/HA) composite scaffolds, and to investigate the influence of components and preparing conditions to their micromorphology. METHODS: The CS-Gel/HA composite scaffolds were prepared by phase-separation method. Micromorphology and porosity were detected by using scanning electron microscope and liquid displacement method respectively. RESULTS: Porous CS-Gel/HA composite scaffolds could be prepared by phase-separation method, and their density and porosity could be controlled by adjusting components and quenching temperature. CONCLUSION: The study suggests the feasibility of using CS-Gel/HA composite scaffolds for the transplantation of autogenous osteoblasts to regenerate bone tissue.
ObjectiveTo review the research progress of the preparation and components of the platelet rich plasma (PRP). MethodsThe recent literature concerning the biological mechanism, preparation, and components of PRP was analyzed and summarized. ResultsThe biological function of PRP depends on a series of intricate cascade of cellular and molecular events. PRP contains different concentrations of platelets, which would release a large number of the activated molecules, and also contains a small amount of white blood cells and red blood cells. The preparation of PRP is based on platelet concentration. Different preparation techniques would lead to different platelet concentrations, recovery ratios, and components. ConclusionThere is no uniform standard for the preparation of PRP. Different preparation methods and technical parameters of PRP will get different components and different concentrations of PRP, which also provide a reference for cl inicians to select the most appropriate PRP for individual patient.