The Bionic Preparation And Properties Study Of Collagen/Gallic Acid-based Adhesive And Self-adhesive Bioelectronics

In recent years,the bionic adhesive based on the mechanism of mussels has became a hot research topic in the world.In most of the relevant researches,dihydroxyphenylalanine(DOPA)was used to modify synthetic polymer to fabricate the bionic adhesives,moreover,the function of the bionic adhesives is single.In the present thesis,gallic acid(3,4,5-Trihydroxybenzoic acid),with extensive sources,low price,strong oxidation resistance,antibacterial and ultraviolet resistance,was applied as an alternative of DOPA to modify a natural polymer material-collagen,which is of good biocompatibility,in vivo degradability,and low immunity,for the purpose of preparing green water-soluble medical soft tissue adhesive.On this basis,two self-adhesive multifunctional hydrogels were developed.The research results are helpful to guide the high-value conversion application of natural products such as collagen and gallic acid in biomedical materials,intelligent sensing and other fields.The main research contents are as follows:(1)Soft tissue adhesive(EPL/GA-Col)was prepared by using collagen(Col)as raw material,gallic acid(GA)and polylysine(EPL)as modifiers.From infrared spectroscopy(FTIR)and nuclear magnetic resonance hydrogen spectroscopy(~1H NMR),the optimal ratio of GA and EPL and the degree of substitution of synthetic product polylysine/gallic acid(EPL/GA)were explored.The structure and performance of EPL/GA-Col were characterized by FTIR,ultraviolet-visible spectrophotometry(UV-Vis),isoelectric point measurement,antibacterial performance and bonding strength test.The results of FTIR and ~1H NMR indicated that EPL/GA and EPL/GA-Col were successfully synthesized.EPL/GA-Col is soluble in water and has excellent antibacterial property.With sodium periodate as oxidant,its maximum adhesion strength to procine reached94.9 k Pa.The results of animal experiments further showed that EPL/GA-Col can promote skin wound healing and prevent tissue bleeding.(2)Modified collagen/nano silver composite material(Ag NPs-MCol)was prepared by mixing EPL/GA-Col(MCol)with silver ammonia solution.UV-Vis,X-ray diffraction(XRD)and electrochemical tests,were carried out to confirm the oxidation-reduction reaction between silver ions and MCol.Transmission electron microscopy(TEM)showed the generated particles size of Ag NPs is mainly between 10-100 nm.In addition,Ag NPs-MCol was mixed with acrylic acid(AA)monomer and glycerin to form adhesive hydrogel(Ag NPs-MCol-PAA)through free radical polymerization.Ag NPs-MCol-PAA hydrogel was tested for its swelling,degradability,mechanical properties,adhesion strength,long-term performance,electrical conductivity,anti-freezing properties,antibacterial performance and animal experiments.The results showed that Ag NPs-MCol-PAA hydrogel had small swelling rate and fast degradation rate;the hydrogel had excellent tensile resistance,compression resistance and toughness;the adhesion strength of the hydrogel reach up to 42.8 k Pa,and it had characteristics of maintaining adhesion strength for a long time(the adhesion strength is still greater than 20 k Pa after 30 days);the hydrogel possessed conductivity up to 6.3 m S/cm,which made it detect human movement and micro-expression changes effectively;the hydrogel had anti-freezing;the superimposed effect of Ag NPs and GA endowed the hydrogel with excellent antibacterial ability,moreover,it had characteristics of anti-UV and wound hemostasis properties.(3)MCol,transition metal carbon/nitride(MXene),AA and glycerin were used as raw materials to prepare MCol-MX-PAA hydrogel via free radical polymerization.The electrochemical,the mechanical property,adhesion strength,conductive property,antibacterial property and anti-freezing were characterized to study the effects of the amount of MXene and the ratio of MCol to AA.The results showed that the MCol-MX-PAA hydrogel could not only detect human movement changes effectively,but also had the potential to monitor changes of glucose concentration;the hydrogel had excellent tensile resistance,compression resistance and toughness,the adhesion strength of the hydrogel to procine reach up to 30.7 k Pa;the hydrogel possessed conductivity of 9.6 m S/cm;under the irradiation of near infrared light(808 nm),the hydrogel showed significant antibacterial activity;the hydrogel had good anti-freezing ability.