In spite of tremendous efforts dedicated to addressing bacterial infections and biofilm formation, the post-antibiotic ear continues to witness a gap between the established materials and an easily accessible yet biocompatible antibacterial reagent. Here we show carbon dots (CDs) synthesized via a single hydrothermal process can afford promising antibacterial activity that can be further enhanced by exposure to light. By using citric acid and polyethyleneimine as the precursors, the photoluminescence CDs can be produced within one-pot, one-step hydrothermal reaction in only 2 h. The CDs demonstrate robust antibacterial property against both Gram-positive and Gram-negative bacteria and, notably, a considerable enhancement of antibacterial effect can be observed upon photo-irradiation. Mechanistic insights reveal that the CDs generate singlet oxygen (1O2) when exposed to light, leading to an augmented reactive oxygen species level. The approach for disruption of biofilms and inhibition of biofilm formation by using the CDs has also been established. Our findings present a potential solution to combat antibacterial resistance, and offer a path to reduce dependence on traditional antibiotics.

The contamination of heavy metals (e.g., Hg, Pb, Cd and As) poses great risks to environment and human health. Rapid and simple detection of heavy metals of considerable toxicity in low concentration levels is an important task in biological and environmental analysis. Among the many convenient detection methods for heavy metals, DNA-inspired gold nanoparticles (AuNPs) (DNA-AuNPs) have been becoming a well-established approach, in which assembly/disassembly of AuNPs serves for colorimetric signaling of the recognition event between DNA and target heavy metals at the AuNP interface. This review focuses on the recent efforts of employing DNA to manipulate the interfacial properties of AuNPs, and summarizes the recent advances in the colorimetric detection of heavy metals. Beginning with the introduction of the fundamental aspects of DNA and AuNPs, three main strategies of constructing DNA-AuNPs with DNA binding-responsive interface are discussed, namely, crosslinking, electrostatics, and base pair stacking. Then, recent achievements in colorimetric biosensing of heavy metals based on the interfacial manipulation of DNA-AuNPs are surveyed and compared. Finally, conclusions and perspectives on the futuristic directions in the field are provided, including the evaluation of the pros and cons of the three strategies, with an expectation of providing a reference for researchers who works in the related field. It is also suggested that manipulation of the interface of DNA-AuNPs represent enormous potential in the pursuit of colorimetric biosensors for a range of analytes of interest.