Heat preservation,antifouling,hemostatic and antibacterial aerogel wound dressings for emergency treatment

Hemostatic dressings with multiple functions are superior to current hemostatic dressings for use in the complex situation of emergency accidents.In particular,the existing dressings lack consideration for the prevention of hypothermic shock after massive hemorrhage.In this study,gelatin(GN)and oxidized pectin(OP)were used for Schiff base cross-linking,and then polyvinyl alcohol(PVA)solution mixed with hemostatic caffeic acid(CA)was introduced to obtain aerogel substrate material(CB)after lyophilization.Polydimethylsiloxane(PDMS)and silver nanowires(Ag NWs)were used to construct a hydrophobic layer,an antibacterial layer and an infrared reflective layer on both sides of CB to prepare a multifunctional aerogel wound dressing with heat preservation,antifouling,hemostasis and antibacterial properties(PDMS-Ag NW-CB).The results showed that the infrared transmittance of PDMS-Ag NW-CB is almost 0,so that thermal energy loss from the body is minimized.The contact angles with water and blood are 129°and 120°,respectively,which have the effect of antifouling.This dressing can absorb blood quickly within 10 min,adhere to and gather platelets,and achieve hemostasis.It has good antibacterial and biocompatibility.Therefore,PDMS-Ag NW-CB has great potential in application to emergency treatment.

Facile preparation of low swelling,high strength,self-healing and pH-responsive hydrogels based on the triple-network structure

A polyacrylic acid(PAA)/gelatin(Gela)/polyvinyl alcohol(PVA)hydrogel was prepared by copolymerization,cooling,and freezing/thawing methods.This triplenetwork(TN)structure hydrogel displayed superior mechanical properties,low swelling ratio and self-healing properties,The superior mechanical properties are attributed to the triple helix association of Gela and PVA crystallites by reversible hydrogen bonding.The characterization results indicated that the fracture stress and the strain were 808 kPa and 370% respectively,while the compression strength could reach 4443 kPa and the compressive modulus was up to 39 MPa under the deformation of 90%.The hydrogen bonding in PVA contributed to maintain and improve the self-healing ability of hydrogels.Every type of hydrogels exhibited a higher swelling ratio under alkaline conditions,and the swelling ratios of PAA,PAA/PVA and PAA/Gela hydrogels were 27.71,12.30 and 9.09,respectively.The PAA/Gela/PVA TN hydrogel showed the lowest swelling ratio(6.57)among these hydrogels.These results indicate that the novel TN hydrogels possess good environmental adaptability and have potential applications in the biomedical engineering and sensor field.