| Collagen is the main structural protein in the extracellular matrix of animals with various biological functions.It is widely distributed in tissues such as skin,bones and muscles of human body,and participates in cell proliferation,differentiation,migration and signal transmission.The role of support,repair,and protection.Compared with traditional collagen,the recombinant human collagen is prepared by using genetic engineering technology at the molecular level,and the recombinant collagen obtained by optimizing the modification is highly consistent with human collagen,and the recombinant collagen has no virus hidden danger and biological pHase.It has high capacitance,excellent water solubility,and can promote excellent characteristics such as cell adhesion,proliferation and differentiation.Collagen is one of the early biomaterials approved by the FDA and CSFDA.Because of its unique biological activity,it is widely used in many fields such as tissue engineering,biomedicine,and drug release.Entrusted by the company,the purpose of this paper is to develop a supplementary treatment based on recombinant human collagen medical dressing for shallow second degree scald and laser plastic surgery.In addition,a self-healing injectable hydrogel was prepared as a carrier for recombinant collagen based on chitosan for use in wound repair and drug delivery.The research results of the thesis are as follows:1.Analysis and activity evaluation of the structure of recombinant human collagen.Recombinant human collagen was determined by infrared,ultraviolet and circular dichroism:1)The recombinant collagen had the largest absorption peak at 225 nm,which corresponds to the maximum absorption peak at 224 nm of standard type III collagen.2)Infrared analysis showed that the recombinant collagen had the same spectral characteristics as the natural collagen amides A,I and III,indicating that the two have similar structures,and the ratio of absorbance at 1235 and1450 is about 1.0,indicating recombinant human collagen.There is a triple helix structure,which is consistent with the characteristics of collagen.3)Circular dichroism analysis shows that the secondary structure content(24.0773523%)of the recombinant collagen in ultrapure water is consistent with the infrared analysis;the unwinding in the acetic acid medium The obtained?-helix ratio was 0.843,which was greater than 50%,indicating that the recombinant collagen was biologically active.4)UPLC-PDA-FLR analysis of recombinant human collagen,in which glycine(25.105ug/ml)and proline(28.826ug/ml)are higher than other proteins,in line with the characteristics of human collagen;cysteine The presence of acid content(1.389 ug/ml)indicates that recombinant collagen belongs to type III collagen.2.Formulation and process research of recombinant collagen dressings.The activity of recombinant collagen is closely related to?helicity.The compatibility of the main and auxiliary materials is used to select other excipients of the dressing.The?-helicality and pH are used as indicators to prepare the dressing preparation,and the best prescription is selected and determined.The preparation process.The samples prepared by the selected prescriptions were subjected to transdermal absorption experiments to investigate the in vitro absorption of recombinant collagen,and the transdermal absorption of recombinant collagen was determined at different time points 10min,20 min,40 min,80 min,160 min,respectively,and the transdermal absorption power was obtained.The learning method is y=2.5727x+72.112,and R~2 is 0.9567.3.Refer to the GB/T16886,ISO10993 medical device biological evaluation series for skin irritation test and sensitization test of medical dressings,and evaluate the primary stimulation index(PII)and sensitization level of recombinant collagen dressing.The experimental results show that the recombinant collagen dressing does not have a stimulating reaction and does not have a sensitizing reaction.Establish a shallow second degree trauma model to explore the repairing effect of recombinant collagen dressing.The experimental results show that the recombinant collagen dressing can promote the repair of wounds.In addition,it is also observed that the skin after the treatment of recombinant collagen is more delicate than the surrounding skin,indicating that the recombinant collagen has a cosmetic effect on the skin.4.Refer to GB/T16886,ISO10993 medical device biological evaluation series,"pHarmacopoeia 2015 edition",DB44/T1360-2014 collagen dressing and other series of national standards and industry standards to evaluate the quality control of recombinant collagen dressings.Including:identification,appearance shape,biocompatibility evaluation,etc.;product technical requirements include product sexual indicators,testing methods,which laid the foundation for the formulation of product quality standards.5.Preparation of a series of injectable hydrogels with self-healing and pH response properties based on chitosan in order to continuously deliver recombinant collagen to promote wound repair.The gel formation time is 20 s and the hydrogel self-healing time is 34 min.The hydrogel exhibits pH-responsive gel degradation and collagen release,and its in vitro release is in good agreement with the Korsmeyer-Peppas equation,index n=0.1,k=0.096,MDT=0.1149 h. |
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