The Research Of Hydrophilic Modification Of Polypropylene Nonwovens For Fat Processing On Viabilities Of Autologous Fat Grafts

ObjectiveRecently,autologous fat grafting has become a popular treatment in aesthetic and reconstructive plastic surgery.Autologous fat granules have been considered as an ideal filling material for they are biocompatible,available in abundance,easily acquired,relatively cheap and safe.However,the unpredictable absorption of fat granules has been a puzzle for clinician and previous research about it haven't got uniform conclusion.The optimal means of harvesting and processing fat granules are still elusive.Based on previous studies,considering the advantages and disadvantages of various process methods,we are looking forward to producing a new kind of filter material for fat granules purification,improving the preservation of fat granules.Methods1.We made SMS nonwovens fiber membrane with smaller fiber diameter and smaller pore size from fine polypropylene particles by melt-blown and spun-bonded process.Then modified the hydrophilia of SMS nonwoven fiber membrane and next produced SMS nonwovens filter mat by overlaying the SMS nonwovens,hot air diversion layer,super-absorbent fiber layer.Finally,we proceed the measurements about basic properties of SMS nonwovens.2.According the GB/T16886 series of standards of national medical instruments and medical materials,we evaluated the biocompatibility of polypropylene SMS nonwovens,including cytotoxicity test,intracutaneous stimulation test and pyrogen test.3.We examined the cell proliferation by CCK8 and analyzed the apoptosis by flow cytometer,figuring out whether the material has toxic effect on cell survival.Then,we cultured ASCs on this material,observing the cell growth.4.We compared the efficiency and effectiveness of 3 various purification methods on fat granules in unit time and in different duration.We compared the structural integrity of purified fat cells by different purification methods.We analyzed the purified adipose tissue whether it contained the cotton fibers.We compared the cell number of SVF and proportion of living cells harvested from the adipose tissues by different purification methods,the percentage of mesenchymal stem cells in the SVF harvested from the adipose tissues by SMS nonwovens mat or cotton cloth filter mat by using flow cytometric analysis.We compared the inflammatory cytokines concentration in the adipose tissue processed by SMS nonwovens mat method or cotton cloth filter mat method in vivo experiment.Results1.We made the SMS nonwovens fiber membrane successfully by melt-blown-spinning process,which contained superior characteristics with small fiber diameter(1um),the average filtering aperture(15.1um),surface roughness(2.29um),contact angle hydrophilic modified(46.20°),liquid penetrant time(4.15seconds).2.SMS nonwovens fiber membrane has good biocompatibility,confirmed by cytotoxicity test,intracutaneous stimulation test and pyrogen test.3.The growth curve of ASCs cultured with SMS nonwovens fiber membrane showed S-shaped basically.There's no obvious change between two groups.It was found that ASCs did not inclined to adhere to the interface of the SMS nonwovens fiber membrane when cultured on the surface of membrane.SMS nonwovens fiber membrane did not promote apoptosis on ASCs.4.Comparing to the cotton cloth filter mat and centrifugation,SMS nonwovens mat has the higher purification effectiveness.There is no significant difference in cellular morphology and fat cell numbers purified by different methods.No cotton fiber was found in the adipose tissue purified by cotton cloth filter mat.(There's no significant difference about viable cells among three groups(p>0.05)).The number of mesenchymal stem cells analyzed by flow cytometry in adipose tissue purified by SMS nonwovens filter mat is much more than by cotton cloth filter mat,but there is no significant difference(p>0.05).In vivo experiment,the inflammatory factors concentration and perilipin immune staining at different points in time didn't have significant difference statistically between SMS nonwovens fiber mat group and cotton cloth filter mat group(p>0.05).Conclusions1.We fabricated a novel SMS nonwovens fiber membrane and composite filter mat for purifying the harvested adipose tissue.2.The novel material has good biocompatibility according to the national evaluate criteria of medical materials,biology and animal trial recommended in GB/T 16886.)3.The SMS nonwovens fiber membrane wouldn't affect normal cellular functions.4.SMS nonwovens composite filter mat has higher effectiveness in purifying harvested fat tissue,reaching much more SVF,and may improve the survival of grafting fat tissue.Compared with cotton cloth filter mat method,SMS nonwovens composite filter mat method wouldn't aggravate inflammatory response in vivo.