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A flexible fabric gas sensor for the detection of sub-ppm-level NH3 is reported in this paper. The reduced graphene oxide (rGO)-polyaniline (PANI) nanocomposite was successfully coated on cotton thread via an in situ polymerization technique. The morphology, microstructure and composition were analyzed by field-emission scanning electron microscope, x-ray diffraction, Fourier transform infrared spectroscopy and Raman spectroscopy. Furthermore, we have studied the responses of the rGO-PANI nanocomposite-based flexible sensors for the detection of NH3 varying from 1–100 ppm, operated at 22 °C. At the optimized concentration of rGO, the response of these sensors increased by 4–5 times in comparison with the pristine rGO and PANI. These flexible sensors exhibited fast response, remarkable long-term stability, good selectivity and a low detection limit. The sensing mechanism for the high sensing performance has been thoroughly discussed and it is mainly due to the distinctive 1D fiber structure, the formation of a p-p heterojunction between the rGO nanosheets and PANI. The rGO-PANI composite-based fabric sensor with low power consumption is a potential flexible electronic device for the detection of NH3.

Background: Increasing bacterial infections as well as a rise in bacterial resistance call for the development of novel and safe antimicrobial agents without inducing bacterial resistance. Nanoparticles (NPs) present some advantages in treating bacterial infections and provide an alternative strategy to discover new antibiotics. Here, we report the development of novel self-assembled fluorescent organic nanoparticles (FONs) with excellent antibacterial efficacy and good biocompatibility.Methods: Self-assembly of 1-(12-(pyridin-1-ium-1-yl)dodecyl)-4-(1,4,5-triphenyl-1H-imidazol-2-yl)pyridin-1-ium (TPIP) in aqueous solution was investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The bacteria were imaged under a laser scanning confocal microscope. We evaluated the antibacterial efficacy of TPIP-FONs in vitro using sugar plate test. The antimicrobial mechanism was explored by SEM. The biocompatibility of the nanoparticles was examined using cytotoxicity test, hemolysis assay, and histological staining. We further tested the antibacterial efficacy of TPIP-FONs in vivo using the S. aureus-infected rats.Results: In aqueous solution, TPIP could self-assemble into nanoparticles (TPIP-FONs) with characteristic aggregation-induced emission (AIE). TPIP-FONs could simultaneously image gram-positive bacteria without the washing process. In vitro antimicrobial activity suggested that TPIP-FONs had excellent antibacterial activity against S. aureus (MIC = 2.0 µg mL-1). Furthermore, TPIP-FONs exhibited intrinsic biocompatibility with mammalian cells, in particular, red blood cells. In vivo studies further demonstrated that TPIP-FONs had excellent antibacterial efficacy and significantly reduced bacterial load in the infectious sites.Conclusion: The integrated design of bacterial imaging and antibacterial functions in the self-assembled small molecules provides a promising strategy for the development of novel antimicrobial nanomaterials.