Bacterial infections have caused serious threats to public health due to the antimicrobial resistance in bacteria. Recently, gold nanoclusters (AuNCs) have been extensively investigated for biomedical applications because of their superior structural and optical properties. Great efforts have demonstrated that AuNCs conjugated with various surface ligands are promising antimicrobial agents owing to their high biocompatibility, polyvalent effect, easy modification and photothermal stability. In this review, we have highlighted the recent achievements for the utilizations of AuNCs as the antimicrobial agents. We have classified the antimicrobial AuNCs by their surface ligands including small molecules (<900 Daltons) and macromolecules (>900 Daltons). Moreover, the antimicrobial activities and mechanisms of AuNCs have been introduced into two main categories of small molecules and macromolecules, respectively. In accordance with the advancements of antimicrobial AuNCs, we further provided conclusions of current challenges and recommendations of future perspectives of antimicrobial AuNCs for fundamental researches and clinical applications.

Elucidating the metabolic mechanism of gold nanoclusters (AuNCs) in bacteria will play a pivotal role in bacterial detection and inhibition. A facile method to investigate the metabolic mechanism of AuNCs is demonstrated in this work. The cysteine-conjugated gold nanoclusters (Cys-AuNCs) were successfully prepared with orange-red fluorescence, high water solubility, and superior biocompatibility by one-pot green synthesis to determine bacterial metabolism. The suggested metabolic process was that Cys-AuNCs were metabolized by Escherichia coli, as verified through a decrease in the fluorescence intensity that was clearly detected at 30 min, indicating the breakage of cysteine on Cys-AuNCs, which was further confirmed via X-ray photoelectron spectroscopy (XPS) that was used to observe the decrease in the size of Cys-AuNCs after being metabolized. The metabolic kinetics of Cys-AuNCs was determined by fitting the change in the fluorescence of Cys-AuNCs as a function of incubation time with E. coli, in which the rate constant could be a useful indicator for detecting different bacteria. In addition, the death of E. coli was characterized by an increase in intracellular reactive oxygen species (ROS) through metabolism. After the metabolism of cysteine on Cys-AuNCs by E. coli, significant intracellular ROS generation was induced by the AuNCs that killed the bacterium due to its lack of the ROS scavenger, cysteine. Our work provides a potential rapid method for bacterial detection and inhibition.

Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.

Influenza, pneumonia, and pathogenic infection of the respiratory system are boosted in cold environments. Low temperatures also result in vasoconstriction, restraint of blood flow, and decreased oxygen to the heart, and the risk of a heart attack would increase accordingly. The present face mask fabric fails to preserve its air-filtering function as its electrostatic function vanishes once exposed to water. Therefore, its filtering efficacy would be decreased meaningfully, making it nearly impracticable to reuse the disposable face masks. The urgent requirement for photothermal fabrics is also rising. Nanobased polyethyleneimine–polypyrrole nanopigments (NPP NPs) have been developed and have strong near-infrared spectrum absorption and exceptional photothermal convertible performance. Herein, the mask fabric used PE-fiber-constructed membrane (PEFM) was coated by the binding affinity of the cationic polyethyleneimine component of NPP NPs forming NPP NPs-PEFM. To the best of our knowledge, no study has investigated NPP NP-coated mask fabric to perform infrared red (solar or body) photothermal conversion efficacy to provide biocompatible warming, remotely photothermally captured antipathogen, and antivasoconstriction in vivo. This pioneering study showed that the developed NPP NPs-PEFM could be washable, reusable, breathable, biocompatible, and photothermal conversable for active eradication of pathogenic bacteria. Further, it possesses warming preservation and antivasoconstriction.