Bio-inspired Multifunctional Structural Color Patches And Their Biomedical Application

Patches play an important role in clinical medicine owing to their broad application prospects in tissue repair and regeneration.With the blossom of emerging healthcare systems,traditional patches can no longer meet the needs of human health.Therefore,patches with multiple functions have emerged,including self-adhesivity,sensing of various physical and biochemical signals,capacity of feedback-regulated controlled drug delivery,etc.Multifunctional patches are different from traditional patches,which are more complicated in terms of the structural composition or the material selection.It is valuable to do research on the preparation of these multifunctional patches with complex structures or materials and explore their applications in biomedicine.In nature world,many organisms have provided critical inspirations for the construction of multifunctional patches.They possess unique micro/nanostructures or chemical composition,endowing them with special functions,such as visual stimulation expression,reversible dry/wet adhesion,ultrasensitivity to vibration and environmental adaptability.With the advancement of biomimetic structure technology,huge progress has been made in the construction of multifunctional patches that mimic the special structure and function of living organisms.These biologically inspired multifunctional patches are widely applied in the fields of tissue engineering,biosensing and signal monitoring.Structural color,derived by interaction between periodic nanostructure and incident light,exists widely in natural creatures.Due to the vivid color,low dissipation loss,and resistance to fading,structural color demonstrates promising prospects in information communication and camouflage.The structural color hydrogel is a typical example.In this paper,combining structural color hydrogels and patch materials,we fabricate several multifunctional structural color patches and explore their applications in biomedical engineering.The specific research contents are as follows:(1)Using monodisperse silica nanoparticles as the building unit,two kinds of inverse opal structural color hydrogels with different properties were generated based on template replication methods.Taking advantage of the constructed structural color hydrogels,three kinds of bio-inspired multifunctional structural color patches were realized including structural color patch with anisotropic surface adhesion,the stretchable,adhesive,and conductive structural color film,as well as the dual-responsive graphene structural color hydrogel film.(2)Based on the constructed structural color patch with anisotropic surface adhesion,its anisotropic adhesion performance was explored by using the two sides of the patch to culture cells;due to the excellent adhesion performance and self-healing ability of polydopamine,adhesion capability of the patch on the surface of porcine myocardial tissue was studied,and the repair of the patterned structural color patch was also realized;benefiting from the bright structural color of the inverse opal structure hydrogel,the patch exhibited color-sensing phenomenon.Given various functions,the patch could be applied for monitoring the cardiac activity.(3)Excellent tensile properties imparted the stretchable,adhesive,and conductive structural color hydrogel film with visual sensing performance and electrical conductivity under deformation.Adhesion and self-healing functions were used for pattern repairing.The film could respond to the motion behavior of different joints of the human body through real-time feedback of dual signals,which demonstrates broad prospects in flexible conductive devices.(4)Based on the constructed dual-responsive graphene structural color hydrogel film,the optical and electrical response to temperature and near-infrared light irradiation were studied respectively.Owing to near-infrared light response performance,intelligent anti-counterfeiting labels could be realized.Graphene-coated film showed great potentials in electrothermal conversion.In addition,the film could act as electronic skin in monitoring external environment changes.