A functional PVA aerogel-based membrane obtaining sutureability through modified electrospinning technology and achieving promising anti-adhesion effect after cardiac surgery

Pericardial barrier destruction,inflammatory cell infiltration,and fibrous tissue hyperplasia,trigger adhesions after cardiac surgery.There are few anti-adhesion materials that are both functional and sutureable for pericardial reconstruction.Besides,a few studies have reported on the mechanism of preventing pericardial adhesion.Herein,a functional barrier membrane with sutureability was developed via a modified electrospinning method.It was composed of poly(L-lactide-co-caprolactone)(PLCL)nanofibers,poly(vinyl alcohol)(PVA)aerogel,and melatonin,named PPMT.The PPMT had a special microstructure manifested as a staggered arrangement of nanofibers on the surface and a layered macroporous aerogel structure in a cross-section.Besides providing the porosity and hydrophilicity obtained from PVA,the structure also had suitable mechanical properties for stitching due to the addition of PLCL nanofibers.Furthermore,it inhibited the proliferation of fibroblasts by suppressing the activation of Fas and P53,and achieved anti-inflammatory effects by affecting the activity of inflammatory cells and reducing the release of pro-inflammatory factors,such as interleukin 8(IL-8)and tumor necrosis factorα(TNF-α).Finally,in vivo transplantation showed that it up-regulated the expression of matrix metalloproteinase-1(MMP1)and tissue inhibitor of metalloproteinase-1(TIMP1),and down-regulated the expression of Vinculin and transforming growth factorβ(TGF-β)in the myocardium,thereby reducing the formation of adhesions.Collectively,these results demonstrate a great potential of PPMT membrane for practical application to anti-adhesion.

Enlisting a Traditional Chinese Medicine to tune the gelation kinetics of a bioactive tissue adhesive for fast hemostasis or minimally invasive therapy

Gelation kinetics is important in tailoring chemically crosslinked hydrogel-based injectable adhesives for different applications.However,the regulation of gelation rate is usually limited to varying the gel precursor and/or crosslinker concentration,which cannot reach a fine level and inevitably alters the physical properties of hydrogels.Amidation reactions are widely used to synthesize hydrogel adhesives.In this work,we propose a traditional Chinese medicine(Borax)-input strategy to tune the gelation rate of amidation reaction triggered systems.Borax provides an initial basic buffer environment to promote the deprotonation process of amino groups and accelerate this reaction.By using a tissue adhesive model PEG-lysozyme(PEG-LZM),the gelation time can be modulated from seconds to minutes with varying Borax concentrations,while the physical properties remain constant.Moreover,the antibacterial ability can be improved due to the bioactivity of Borax.The hydrogel precursors can be regulated to solidify instantly to close the bleeding wound at emergency.Meanwhile,they can also be customized to match the flowing time in the catheter,thereby facilitating minimally invasive tissue sealing.Because this method is easily operated,we envision Borax adjusted amidation-type hydrogel has a promising prospect in clinical application.