Preparation Of Polyurethane/BSP Composite Hydrogel And Its Application As A Wound Dressing

Skin will often be damaged by burns,scalds,incisions,etc.The surface of the wound exposed to the air may be susceptible to bacterial infections that exacerbate the seriousness of the wound,so an ideal wound dressing is needed.Polyurethane has the advantages of good mechanical properties,biocompatibility,and adjustable properties.Hydrogels made from polyurethane have the advantages of polyurethane,but also have the advantages of keeping the environment moist,providing sufficient gas exchange,absorbing wound liquid,and preventing secondary pollution.As a natural polysaccharide,bletilla polysaccharide is low cost and easy to obtain.It has good biocompatibility,high liquid absorption capacity,and sufficient cell proliferation activity,and it also have functions of astringent,hemostatic,anti-inflammatory,bacteriostatic,antioxidant,and promote tissue regeneration and body.In this paper,BSP polysaccharides are introduced into polyurethane hydrogels to prepare a new type of polyurethane/BSP hydrogel(WBPU-BSP),which is expected to be used as a wound dressing.The work of the second chapter,a double-bond-terminated waterborne polyurethane emulsion(WBPU)was prepared by using Hydroxyethyl methacrylate(HEMA),2-Hydroxyethyl acrylate(HEA)and Poly(ethylene glycol)Methacrylate(PEGMA)as three end-capping agents.Polyurethane-based composite hydrogels(WBPUC)were then made from acrylamide(AM)of different qualities.The results of IR,SEM and XRD characterization of the hydrogel showed that the polyurethane-based composite hydrogel has porous structure.The water swelling curve of the gel sample showed that when the AM content increased,the equilibrium swelling ratio of the gel increased first and then decreased.The equilibrium swelling of the WBPUC3 hydrogel is relatively high,reaching 15.5,and the WBPUC hydrogel has a certain pH sensitivity.The results of mechanical experiments showed that with the increase of AM content,the compression strength of WBPUC samples gradually increased and the compression modulus gradually decreased,the compression strengths of WBPUC3 and WBPUC7 hydrogels are 0.47 MPa and 0.50 MPa,respectively,and have good compression performance.The work of chapter three,the soft segment was changed to PEG and PCL with different mass ratios,and polyurethane-based composite hydrogels(WBPUC)were prepared.The results of IR,SEM and XRD characterization of the hydrogel structure were showed hydrogels have porous structure.The swelling performance test results showed that the dry gel has good swelling performance in distilled water.The equilibrium swelling ratio of WBPUC10 hydrogel is 15.5.As the PCL content increases,the equilibrium swelling ratio of the sample gradually decreased,and the compression of WBPUC8~WBPUC12 hydrogel reduced gradually,and the strength gradually increased.The compressive strength of WBPUC12 hydrogel was 0.73 MPa,which has good compression resistance.The results of in vitro hydrolytic degradation experiments showed that when the mass ratio of PEG and PCL was 1:1,the hydrogel had the largest degradation rate.In Chapter four,PEG and PCL with a mass ratio of 1:1 were used as the soft segment and IPDI was used as the hard segment to prepare a double-bond end-group waterborne polyurethane.KPS,PEGDA,AM and different mass faction of BSP were adding into polyureathane to prepared WBPU-BSP hydrogels.The results of IR,SEM and XRD analysis showed that WBPU-BSP hydrogels had porous structure.The equilibrium swelling ratios of WBPU-BSP0%and WBPU-BSP5%gels in water were 13.8 and 17.8,respectively,WBPU-BSP gel had good swelling performance.The equilibrium swelling ratio in simulated body fluids reduced,but it still has good swelling performance.The compressive strength curve showed that with the increase of BSP content,the compressive strength of WBPU-BSP0%~WBPU-BSP5%hydrogel increased first and then decreased,and the maximum compressive strength of WBPU-BSP4%hydrogel was 1.07MPa,which had good Compression resistances.Water vapor transmission tests showed that the water vapor transmission rates of WBPU-BSP3%and WBPU-BSP4%hydrogels were2229.6±85.1g/m~2/day and 2013.4±129.3g/m~2/day,respectively,which met the requirement of water vapor permeability of dressing.In Chapter five,we studied the antibacterial properties and biocompatibility of the WBPU-BSP hydrogel synthesized in Chapter four.The results of antibacterial experiments showed that the hydrogel itself can inhibit E.coli and S.aureus to a certain extent.The WBPU-BSP4%hydrogel had good antibacterial performance against E.coli and S.aureus,which could prevent secondary infections of wounds.The test results of scavenging hydroxyl radicals showed that when the concentration of the sample extract was 1mg/mL,the rate of scavenging hydroxyl radicals of the WBPU-BSP4%hydrogel was 35%.The hemolysis test results showed that the hemolysis rates of WBPU-BSP0%,WBPU-BSP2%,and WBPU-BSP4%were 3.5±0.2%,2.8±0.1%,and 2.5±0.1%,respectively,which met the biological clinical use standards.The cytotoxicity results of the hydrogels tested by the MTT method showed that the cell survival rate of 10-fold dilution of WBPU-BSP 4%was101.4±3%,which was non-cytotoxic.Animal experiments showed that the hydrogel dressing was better than vaseline gauze in promoting wound healing and forming regenerated epidermis in mice and could be used as a potential wound dressing.