| Bacterial infections seriously affect health and quality of life and even endanger lives in some critical conditions.The detection and treatment of bacterial infections are important aspects to prevent and control bacterial infectious diseases,to protect health and lives,and to reduce national public health expenditures.It is of great significance to develop efficient and inexpensive strategies for bacterial detection and inhibition.Hydrogels have excellent designability by combining different components and functions and have been demonstrated promising in bacterial detection and antibacterial purpose.In particular,optically functional composite hydrogels,which incorporate optically functional components in the hydrogels,have been recently developed for bacterial detection and inhibition.These optically functional composite hydrogels can identify or treat bacterial infections based on light,which have the advantages of visual output,high spatial and temporal precision,and noncontact.However,there are still some challenges:（1）the existing optically functional composite hydrogels used for bacterial detection always need to be equipped with specific equipment for excitation and signal output,which is not suitable for direct detection.（2）In the process of photodynamic therapy（PDT）,ineffective utilization of excitation light hinders the effects of PDT.Besides,to improve the photothermal therapy（PTT）effect,a high local temperature is required,which may cause damages to normal tissues.In this thesis,through the rational design and structural control of the functional components of the optically functional composite hydrogels,by introducing photonic crystals,optimizing optically functional components,and constructing responsive hydrogels,etc.,a series of optically functional composite hydrogels with the capabilities of self-reporting or light-triggered bacterial inhibition were obtained by in-situ photopolymerization or physically cross-linking.The main research contents of this thesis are as follows:（1）Gelatin-based photonic composite hydrogels with bright structural colors were prepared by the self-assembly of carbon-coated Fe3O4 nanoparticles under magnetic field and in-situ photopolymerization of acrylamide,N,N’-methylenebis-（acrylamide）,and gelatin methacrylate.The color of the photonic composite hydrogels changed from green to red due to the specific hydrolysis of gelatin triggered by gelatinase or the metabolite of Pseudomonas aeruginosa（P.aeruginosa）,which can be applied to detect P.aeruginosa.（2）Photonic composite hydrogels were obtained by UV light-initiated crosslinking of poly（ethylene glycol）phenyl ether acrylate with the self-assembled Si O2 nanoparticles colloidal array.Photonic composite hydrogels can prompt the photosensitizers or photocatalysts with matched absorption,which were deposited on the surface of the photonic composite hydrogel,to generate more reactive oxygen species（ROS）based on the slow photon phenomenon of photonic crystals and multiple scattering effects of the colloidal nanoparticles.Compared with pure hydrogels,photonic composite hydrogels greatly enhanced the production of ROS to 2.7 times,and the antibacterial ratio increased by 38.7%under light irradiation,realizing effective photodynamic antibacterial.（3）Alginate-Mn O2-Ag3PO4 complex was prepared via a biomimetic mineralization and ion exchange process.The calcium alginate-Mn O2-Ag3PO4 composite hydrogels were obtained by the physically cross-linking of calcium ions.The photothermal conversion and the generation of ROS can be achieved under simulated solar light irradiation.The photothermal effect of the composite hydrogel enhanced the bacterial membrane permeability,further increasing the antibacterial effect of ROS.Besides,the in-situ antibacterial effect of the composite hydrogels in the infected skins model was demonstrated.（4）Self-adhesive photothermal antibacterial hydrogels were prepared by UV light-initiated in-situ photopolymerization of acrylamide and N,N’-methylenebis-（acrylamide）in the presence of polydopamine,polyethyleneimine,and reduced graphene oxide（r GO）.Through adjusting the contents of dopamine and r GO,the adhesion,photothermal,and mechanical properties of the hydrogels were optimized.Furthermore,with the assistance of solar light,the antibacterial activity of the hydrogels increased by 30.6%,and the cutaneous wound repair accelerated by 16.1%due to the localized heat around the wound. |
