Study On The Biological Activity Of Nanofiber Hydrogels Encapsulating Polydeoxyribonucleotide And Its Treatment Of Chronic Soft Tissue Ulcer

part iPreparation of self assembled nanofiber hydrogel and detection of its encapsulating PDRNObjective:This study investigated a novel nanofiber hydrogel composed through layer-by-layer(LbL)self-assembly,in which PDRN was encapsulated,and the morpholbgy,particle size,encapsulation rate,drug loading efficacy,release efficiency and structure validation were detected.Methods:IKVAV,RGD and FGL-PA were screened and combined to produce an optimal vehicle nanofiber hydrogel through LbL assembly.Subsequently,the aqueous PDRN was encapsulated into this nano fiber at the appropriate concentration.The morphological structure was observed by transmission electron microscope(TEM),the particle size was measured by dynamic diffractometer,the encapsulation rate?drug loading efficacy and release efficiency were detected by ultraviolet(UV)spectrophotometer,and the crystal structure was verified by crystal difiractometer.Results:Nanofiber hydrogel encapsulated PDRN was confirmed by TEM.The results indicated that the optimal proportion of the nano fiber gel was IKVAV:RGD:FGL-PA=1:1:1,the optimal concentration was 0.6 mg/ml and the best proportion of PDRN in hydrogel was 50%,as determined by observing the liquidity,diffusion time and viscosity.The mean particle widths of the nanofiber gels was 212 nm,the results of UV spectropho to metric analysis revealed that the encapsulation efficiency of PDRN samples was>90%,with a mean encapsulation efficiency of 96.6 ± 1.75%,and the mean drug loading of 5.15 + 0.04 mg/g.The study of sustained release properties showed that the release time of this hydrogel was longer than 4 days.The results of crystal structure validation indicated that the peak number and time of PDRN nanoflber gel was similar to that of the PDRN stock solution,which confirmed that the structure of PDRN encapsulated in the nanofiber gel was unvaried.Conclusion:PDRN nanofiber hydrogel with high drug loading.high encapsulation rate and long sustained release properties,it is an ideal substrate repair material.Part 2Detection of biological activity of PDRN.sNAG nanofiber and sNAG nanofiber hydrogel encapsulation PDRNObjective:To study the effects of PDRN,sNAG nano fiber and sNAG nano fiber hydrogel encapsulation PDRN on cell proliferation and angiogenesis.Methods:The effects of PDRN,sNAG nanofibers and sNAG nanofiber hydrogel encapsulation PDRN on cell proliferation were studied by CCK8;The effects of PDRN,sNAG nano fibers and sNAG nanofiber hydrogel encapsulation PDRN on cytokine release and vascular regeneration were studied by RT-PCR and Western-blotting;The effects of sNAG nanofibers and sNAG nanofiber hydrogel encapsulation PDRN on cell migration were studied by three dimensional mechanism invasibn experiment;The effects of sNAG nanofibers and sNAG nanofiber hydrogel encapsulation PDRN on blood compatibility were studied by plasma and platelet protein adhesion experiments.Results:Through the above experiments we found that PDRN,sNAG nano fibers and sNAG nanofiber hydrogel encapsulation PDRN could promote cell proliferation,cytokine release and cell migration,and the blood compatibility of sNAG nanofiber hydrogel encapsulation PDRN is the best.Conclusion:PDRN,sNAG nanofibers and sNAG nanofiber hydrogel encapsulation PDRN can promote cell proliferation and vascular regenerationPart 3The Efficacy of PDRN.sNAG nanofiber and sNAG nanofiber hydrogel encapsulation PDRN in treatment of skin ulcer in diabetic miceObjective:To compare the effect of PDRN?sNAG nanofiber and sNAG nano fiber hydrogel encapsulation PDRN on diabetic mice skin ulcer by animal experiment.Methods:First of all,we should establish the model of diabetic mice skin ulcer and group them.After receiving PDRN?SNAG nanofiber and sNAG nanofiber hydrogel encapsulation PDRN treatment,the expression of related cytokines in diabetic mice was detected by RT-PCR and Western-blotting,respectively.Subsequently,cell proliferation,inflammatory infiltration and angiogenesis were observed by histological staining.Finally,the degree of wound healing and healing intensity was evaluated by comparing the area of open wound,the extent of wound contraction and the area of epidermal regeneration of each group.Results:By comparing the results of RT-PCR and Western-blotting,we found that PDRN.sNAG nanofiber and sNAG nanofiber hydrogel encapsulation PDRN could increase the expression of cytokines in diabetic mice,and the expression of cytokines in sNAG+PDRN group was the most obvious.By measuring the area of open wound,the extent of wound contraction,the area of epidermal regeneration and the strength of wound healing,we found that PDRN,sNAG and sNAG+PDRN can promote the healing of ulcer in diabetic mice,in which sNAG+PDRN treatment group had the shortest healing time and the best healing strength.Conclusion:The use of PDRN,sNAG and sNAG+PDRN in the treatment of skin ulcers in diabetic mice can promote ulcer surface crusting local cell proliferation,cytokine release and promote angiogenesis,in which sNAG+PDRN group has the best effect,indicating that sNAG combined with PDRN has a synergistic effect.This study provides a new research direction for the future tissue engineering wound repair.