Preparation Of Multifaceted Nanogels From Steam Flash Explosion Treated Yak Horn Powder

As the volume of livestock slaughter increases year by year,the exploitation of slaughtered animal by-products is a serious challenge for veterinary public health.According to the report of National Beef Cattle and Yak Industry Technology System: the slaughter volume of yak in China is 3 million head in 2022.Yak slaughter by-products,yak horn,are in large stock,metabolize slowly and easily cause environmental pollution.The "Thousand Gold Rhinoceros Horn San" recorded in Sun Simiao’s "Thousand Gold Essential Formula" in the Tang Dynasty is a miraculous treatment for internal attack of carbuncle and heat poison and sores on the throat and tongue.Modern Chinese veterinary theory that rhinoceros horn powder has the effect of clearing heat and detoxifying,cooling the blood and calming the mind.In China,rhinoceros horn has been banned as a medicine,can we use yak horn instead? Another animal trauma most of the open infected wounds,it is difficult to find in time to bail out the wound,often leading to the death of the animal infection.In order to explore the use of yak horn instead of rhinoceros horn and to develop nanogels with good disinfection effect and effective prevention of animal trauma infection,this study proposes to use steam flash explosion technology to treat yak horn powder and assemble multi-nanogels by protein structure analysis,using keratin nanoparticles with high biocompatibility and transdermal properties as delivery units,glutaraldehyde as cross-linking agent and black gadfly chitosan as cationic ligand molecules.It can be used for both skin,mucous membrane and wound disinfection treatment,as well as applied to open infected wounds to form a thin film.The released chitosan can inhibit bacterial reproduction and keratin can promote wound healing.In order to further verify the clinical effect of the gel,a more difficult to cure diabetic skin ulcer animal model was chosen to realize the anti-infection and pro-healing effect of the gel on skin wounds.The experimental results were as follows:(1)The solubility of yak horn protein increased,the enzymatic properties improved and the bioavailability increased after steam flash explosion treatment.The yak horn protein retained most of the protein backbone after steam flash explosion treatment,and the disulfide and hydrogen bonds were broken,and the α-helical and β-turned angle structures were significantly deconstructed;the water solubility and enzymatic accessibility of keratin increased,and the solubility of yak horn protein reached 9.6%;the yield was higher than the traditional alkaline hydrolysis using deep eutectic solvent extraction,reaching 86.4%.(2)Steam flash explosion is a more ideal method for the preparation of chitosan nanoparticles.Regional particle size scans showed that the size range of the planar nanoparticles was 59-162 nm under pressure treatment at 1.60 MPa.high purity chitosan(91.24%deacetylation)could be obtained by deacetylating gadfly chitin,while maintaining the polymer backbone.The ligand activity of this chitin material was improved and the temperature sensitivity of the material was also improved.(3)The five types of yak horn protein multi-nanogels prepared were effective in preventing infection and promoting wound healing.The wound closure rate reached 73.48% in a short period of 3-12 days,followed by Gel 0.5% group with 66.22%,C21 group with 55.28%,Gel1.0% group with 33.89%,and C2020 group with 25.85%.Compared with the wound closure rate of 19.53% in the unmedicated DM mice group,all five groups of gels had more obvious effects in promoting the healing of diabetic foot ulcers.Conclusion: It is technically feasible to prepare yak horn protein disinfection gel and trauma anti-infection gel by replacing traditional Chinese veterinary medicine rhinoceros horn with yak horn,combining steam flash explosion technology and multivariate nano-assembly process.The series of products are easy to use,non-irritating,with long-lasting efficacy,good antibacterial effect and strong wound healing ability,which opens up a new way for the highvalue utilization of yak horn,a by-product of yak slaughtering.