Preparation And Properties Of Medical Spunbond-meltblown Composite Nonwoven Fat Graft Filter

Autologous fat transplantation has good development and prospects in the soft tissue repair,breast and buttocks augmentation,and other cosmetic surgery field.How to improve the survival rate of transplanted fat and reduce the rate of graft fat absorption and other complications has been the research focus of researchers in recent years.Autologous fat transplantation technology includes three aspects,which are fat suction,purification and injection respectively.Purification technology is the key to affect the survival rate of transplanted fat in this technology,so,improving the purification effect can effectively improve the fat survival rate.At present,there are three kinds of purification methods that are mainly used clinically,which are static method,medical cotton gauze filtration method and centrifugal method.However,these three methods all have some deficiencies.For example,the static method takes a long time with a low purification rate in fat purification.Although the cotton gauze filtration method is easy to operate,it has the risk of the fibers entering the adipose tissue.The fat content obtained by centrifugation is highest,but studies have shown that increased centrifugal velocity can damage fat cells.Therefore,it is necessary to study a new fat purification method to improve the filtration efficiency of fat purification.The polypropylene spunbond-meltblown nonwoven material has the advantages of stable chemical properties,smooth surface and small pore size,and can be used as a new filter medium instead of medical cotton gauze to purify fats.In this paper,the mechanism of purification of fat by composite filter was studied firstly.Based on this principle,a reasonable composite filter structure and the non-woven material types of each layer were designed to achieve the fat purification effect of intercepting fat cells,filtering liquid and oil and other impurities.Polypropylene spunbond-meltblown nonwovens can’t filter the liquid in the fats due to the hydrophobic nature of the fibers and the material structure.In this paper,we study the hydrophilic finishing technology of polypropylene spunbond-meltblown nonwovens to determine the best finishing parameters.A kind of hydrophilic polypropylene spunbond-meltblown nonwoven material was prepared as a fat filtration layer.Meanwhile,the structure and properties of the nonwoven materials used in the fat filtration layer and other layers were also characterized.At the same time,the forming process and structure of the spunbond-meltblown composite non-woven filter materials for the fat transplantation was studied through the research of the die design and the process parameters.In this paper,in vitro cytotoxicity test to evaluate the biocompatibility of spunbond-meltblown composite nonwoven filter materials By comparing with medical cotton gauze filter method and centrifugal method,the purification effect of composite filter material in fat purification was explored.Through the above research,the following conclusions are drawn:(1)The structure and material of composite spunbond-meltblown nonwoven for fat graft from top to bottom in order is the fat filter layer(hydrophilic polypropylene SMS nonwovens),the acquisition distribution layer(ES thermal bonding material),the absorbent core sheet(SAF and wood fibers composite nonwoven),support layer(needled-punched nonwoven),impervious layer(polypropylene SMS nonwoven).(2)The best heat setting process parameters in bowl-shaped medical spunbond-meltblown composite nonwoven fat graft filter forming process: cavity block and male mold temperature is 120 ℃ and 110 ℃ respectively,heat setting time is 20 ~ 30 min,cooling time is 60 min.At this point,SAF and wood fiber in composite filter fractures less.Filter has a stable bowl structure and is easy to recover after pressing with appropriate thickness and better flexibility.(3)The optimum process of hydrophilic finishing method for the modification of polypropylene spunbond-meltblown nonwovens: hydrophilic agent concentration of 7%,drying temperature of 100 ℃,drying time of 140 s.The hydrophilic polypropylene SMS nonwovens prepared by this process had a contact angle of 46.2 ° and a liquid strike-through time of 3.54 s.Part of the polypropylene SMS non-woven surface covered with a hydrophilic film after hydrophilic finishing,pore size distribution is more concentrated.Compared with the medical pad,the surface of the spunbond-meltblown composite nonwoven filter is smoother with better fluid absorption and evener liquid diffusion.The fat purification treatment can be carried out more effectively by this method.(4)Hydrophilic finished polypropylene spunbond-meltblown nonwoven material is noncytotoxic proved by vitro cytotoxicity test evaluation,and can be used as fat filter layer to contact fat cells directly in fat purification.The result of the comparison of the effects of the fat purification by three methods of the spunbond-meltblown filtration method and the medical cotton gauze filtration method and the centrifugation method concludes that the filtration efficiency efficacy of the spunbond-meltblown composite nonwoven filter is the highest one among the three methods,this purification method is the best of the three methods after the comprehensive evaluation.In summary,as a new type of filter material,medical spunbond-meltblown composite nonwoven filter can be used as a kind of purification material in fat transplantation technology.It has the advantages of purification efficiency improvement,simple operation,safety,etc.,and also has broad application and development prospects.