The Preparation Of Polymer Tissue Adhesive And Protective Materials And Their Applications In The Field Of Intelligent Skin Materials

Recently,with the development of medicine,biology,chemistry and materials science,biomedical materials have played more and more important roles in healthcare of diagnostic treatment and rehabilitation nursing.As one typical type of biomedical materials,biomedical polymer composites can combine various components with different properties and structures,which makes them have good mechanical properties,physiological inertia and biocompatibility,in vivo and in vitro stability and easily synthesis,modification and processing.Biomedical polymer composites are widely applied in artificial organs preparation,tissue engineering and regenerative medicine.Skin is the outermost organ of human body with multiple functions of protecting,modulating body temperature,exchanging substances,maintaining stability of substances like water,keeping metabolic balance and sensing external stimuli.Therefore,it is significant to keep integrality of the skin.However,skin is easy to suffer injuries like skin burns and chronic skin injuries.These skin injuries usually take a long time to recover and the recovery effect is not ideal,which has always been the difficulty in the medical field.It is an effective solution of utilizing the biomedical materials with superior performances in skin wounds healing and skin protection.This thesis performed the design and preparation of polymer tissue adhesive and protective materials and investigated their applications in the field of intelligent skin materials,which expanded the applications of biomedical materials on the surface of skin to play functional roles in skin wounds healing and skin protection.The detailed research contents are as follows:(1)Inspired by the multi-hydrogen bonds interactions of nucleobases,we combined the concept of tissue adhesion and constructed a tough,stretchable,and selfadhesive strain sensing hydrogel PAAm-GO-A+T of which the backbones are modified with nucleobase A(adenine)and T(thymine).The mechanical properties,adhesion performances,dynamic adaptability and strain sensing related properties of this hydrogel were also demonstrated.The characterizations indicated that this hydrogel has good tensile and compression performances,the tensile strength was up to 650 KPa.This hydorgel exhibited different adhesion strength for various substrates(metal,glass,silicone,hogskin).This hydrogel also has good dynamic mechanical property,and the maximum shear strain it can withstand was close to 400%.When this hydrogel was adhered on the surface of skin and deformed with body motions,it can provide realtime strain response curve and has good strain sensitivity and stability.PAAm-GO-A+T hydrogel effectively solved the poor self-adhesion of strain sensors on surface of skin and can be applied in healcare monitoring as flexible biosensor.(2)For the deficiency of the present synthetic tissue adhesives,combined with the performance characteristics of polysiloxane,a functional skin tissue adhesive was designed and prepared.It is composed of polysiloxane prepolymer PDMSn-PBAMSm with side functional groups of benzylaldehyde and terminal group vinyl,crosslinker PHMS and Pt catalyst.Among them,the prepolymer,crosslinker and catalyst were mixed and applied on the surface of skin,and then the hydrosilylation was occurred in situ to obtain polysiloxane elastomer.Meanwhile,the side groups benzylaldehyde covalently reacted with the amine groups on surface of skin to achieve tissue adhesion.The characterizations indicated that this polysiloxane elastomer has similar elastic modulus like skin and good adhesion for hogskin,the maximum of shear adhesion,tensile adhesion and 180° peel-off strength were 77.6 KPa,87.9 KPa and 0.68 N/cm respectively,which is far higher than the adhesion strength of control group without functional benzylaldehyde groups.The rheology tests indicated that this material has rapid in situ curing process at room temperature.The biocompatibility and in vitro stability of this polysiloxane ealstomer were also good.The polysiloxane skin tissue adhesive in this part overcame the deficiency of the present synthetic tissue adhesives incompatible with soft tissue like skin on mechanical modulus and has good application prospects.(3)Combining with the performance advantages of polysiloxane and polyvinyl alcohol,a skin barrier material PSI-PVA was constructed to provide protection for the skin.PSI-PVA was prepared via in situ ionic crosslinking on the surface of skin with a mixed solution of hydrophilic modified polysiloxane and polyvinyl alcohol,which is simple and easy to operate.The characterizations indicated that PSI-PVA exhibited good stretchability and mechancial strength in dry and wet(the mass fraction of water was 5%～15%).PSI-PVA exhibited good hydrophilicity,water absorption stability and breathability.When the mass fraction of polyvinyl alcohol was 20%,the swelling ratio was 149%and the water vapor transmission rate was 1072 g/(m2·d),and PSI-PVA could keep stable after absorbing water.PSI-PVA has good affinity and biocompatibility with skin and can be easy to remove with water when applied to skin.In addition,this material also can be covalently modified,the prepared PSI(UV)-PVA film can shield UV radiation by linking the UV-absorbing group hydroxy benzophenone into the main chain of polysiloxane so that to provide good sun protection for skin.