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A broad-spectrum antibacterial system was produced in which silver nanoparticle-conjugated graphene quantum dots were utilised as a blue light-enhanced nanotherapeutic for efficient ternary-mode antimicrobial therapy.

This paper proposes a highly efficient antibacterial system based on a synergistic combination of photodynamic therapy, photothermal therapy, and chemotherapy. Chitosan oligosaccharide functionalized graphene quantum dots (GQDs-COS) with short-term exposure to 450 nm visible light are used to promote rapid healing in bacteria-infected wounds. The GQDs undergo strong photochemical transformation to rapidly produce radical oxygen species and heat under light illumination, while the COS has an innate antimicrobial ability. Moreover, the positively charged GQDs-COS can easily capture bacteria via electrostatic interactions and kill Gram-positive and Gram-negative bacteria by multivalent interactions and synergistic effects. The antibacterial action of this nanocomposite causes irreversible damage to outer and inner bacterial membranes, resulting in cytoplasm leakage and death. The system has good hemocompatibility and low cytotoxicity and can improve the healing of infected wounds, as demonstrated by the examination of pathological tissue sections and inflammatory markers. These results suggest that GQDs anchored with bioactive molecules are a potential photo-activated antimicrobial strategy for anti-infective therapy.

A novel micropatterned smart template based on transparency photolithography allows the spatial control of cell micropatterning.By utilizing the photoinduced reaction of azobenzene ligands and cyclodextrin-terminated alkanesilane via host-guest recognitions, cells can be easily controlled to adhere reversibly in well defined areas.

Amino-functionalized graphene oxide (GO-NH2) was prepared for enhanced antibacterial properties through excellent photothermal efficiency. This nanosheet could easily target the bacterial surface through electrostatic attraction. Upon white light irradiation, GO-NH2 with superior antibacterial efficacy could inhibit the growth of Gram-negative and Gram-positive bacteria, resulting in an increase to 32-times more than the antibacterial activity of GO alone. Through studies of the antibacterial mechanism, it was found that the nanosheets could destroy the cytomembrane of bacteria, resulting in cytoplasmic leakage. Moreover, the analysis of cell proliferation indicated that the nanosheets had good biocompatibility. This work indicates that graphene oxide could be used as a new nanostructured carbon material to construct an antimicrobial agent for photothermal therapy in the biomedical field.