Preparation And Properties Of High Performance Acellular Dermal Matrix Antimicrobial Dressings

At present, preparation for collagen dressings using pigskin as raw material to repair the skin injury has become a hot topic. However, there are some disadvantages of traditional method to prepare acellular dermal matrix (ADM), such as poor permeability, low antibacterial properties, and poor biocompatibility and so on, which seriously limited the acellular dermal matrix dressing in clinical application.In view of the above problems, this paper combined with the clinical requirements for wound dressing and structure features of pig skin, guided by the principle of tissue engineering and based on the early laboratory research and the latest research results, adopting new technology processing lyophilized pigskin, removing the hair root sheath and other fibrous stroma, improving permeability, compositing carboxymethyl chitosan and chondroitin sulfate and other natural polysaccharides, and cross-linked with glutaraldehyde, improving antibacterial properties and biological activity, to obtain the high performance of acellular dermal matrix antimicrobial dressing. The key research contents and results of this paper are as follows:(1) First of all, the preparation process of acellular dermal matrix were studied: after keratinase treatment, the water vapor permeability and porosity of acellular dermal matrix is better than that of traditional method produced, Therefore, in the process of preparation of acellular dermal matrix, we increase the keratinase treatment, the specific process method:Freeze dried pigskin, soaking, degreasing, alkali expansion and elimination of alkali, keratinase treatment, two enzyme expansion treatment, PBS liquid cleaning, and package.(2)the keratinase dosage has certain effect on the water vapor permeability, porosity and tensile strength of acellular dermal matrix:with the increase of the keratinase dosage, water vapor permeability, porosity, matrix increased, tensile strength decreased, but the decrease range is not big, it can maintain the collagen fiber structure stability in certain degree, this shows that keratinase treatment basically is expected to achieve the goal of improving water vapor permeability of acellular dermal matrix. In terms of the mechanical property of matrix and cost, the keratinase dosage is0.3%.(3)compositing carboxymethyl chitosan on the acellular dermal matrix, the effect of Carboxymethyl Chitosan on the antibacterial property of the matrix was studied, and it provides a reliable basis for the preparation of antimicrobial dressing. Results of the antimicrobial test showed that:compared with conventional matrix, after compositing the inhibitory rate increases,which shows that:to some extent,the antibacterial performance of matrix is improved, and Carboxymethyl Chitosan has important influence on the antibacterial properties of matrix.(4)compositing and crosslinking natural polysaccharide on acellular dermal matrix, its influence on the tensile strength,degradation time in vitro and other chemical and physical properties of matrix. The experimental results show that: after cross-linking carboxymethyl chitosan, hyaluronic acid, chondroitin sulfate, the tensile strength, water vapor rate, degradation time in vitro and porosity of matrix increase.(5)according to the above (1),(2),(3),(4) results and the tissue engineering principle, combined with the dressing performance requirements, we prepare the high performance of acellular dermal matrix antimicrobial dressing, and detect the main performance of dressing. The results show that:after glutaraldehyde crosslinking, the dressing color is micro yellow, pores visible surface flat, smooth, soft and flexible, no visible impurities. as the result of scanning electron microscopy:Porous network structure of collagen fibers is loose, the porous structure is rich, it is suitable for cell proliferation and blood vessel. tensile strength is10.66MPa, about5times of that of pure collagen membrane, the tensile strength can satisfy the clinical requirements for dressing. Water vapor rate is3640g.m-2.24h-1, which shows that: it has good water vapor permeability. porosity is about81%, and it is suitable for wound healing. degradation time is about24.33h. pH is6.5-7.5, in accordance with the relevant standard of dressing. Antibacterial experiment showed that, dressing has certain antibacterial performance, effectively reduce the wound infection.The high performance acellular dermal matrix antimicrobial dressing has certain antibacterial properties and biological activity, basically meet the clinical requirements for dressing, it is expected to be used in clinical, promote wound healing, and lay the foundation for the later application research.