Novel Self-assembled Organic Nanoprobe for Molecular Imaging and Treatment of Gram-positive Bacterial Infection

Abstract

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.

On-demand storage and release of antimicrobial peptides using Pandora's box-like nanotubes gated with a bacterial infection-responsive polymer

“…The rapid “swelling-collapsing” transformation of the PMAA “gate” was evaluated by the aggregation-induced emission (AIE) fluorescence labelling technique. AIE luminogens (AIEgens) are fluorescent when molecularly aggregated while nonluminescent when dissolved 51-55. In the present study, we immobilized the AIEgens (TPE-NH 2 ) on Ti-NTs-P by an amide coupling reaction (Figure 2C).…”

Preparation, Synergism, and Biocompatibility of in situ Liquid Crystals Loaded with Sinomenine and 5-Fluorouracil for Treatment of Liver Cancer

“…The maximum absorption wavelength (λ max ) was determined by UV/Vis spectroscopy as follows: supernatants from the positive control group were placed in quartz cuvettes with a 1 cm path in a total volume of 2.0 mL, then UV/Vis spectra (200–800 nm) were recorded to determine the λ max value. To express the in vitro hemolytic properties of our samples, the percentage of hemolysis was calculated as follows: 26 …”

Antimicrobial and antibiofilm activity of the EeCentrocin 1 derived peptide EC1-17KV via membrane disruption

“…Cells incubated with 0.1% Triton X-100 was used as 100% haemolysis. The haemolysis percentage was calculated as previously described [26]. For cytotoxicity assay, cell lines (Raw 264.7, GES-1 and human L02) and spleen cells obtained from healthy mice with aseptic technique were suspended in medium to a density of 1 £ 10 7 cells/ml, added with two-fold serially diluted peptides, from 16 to 1024 mg/ml, and incubated for 48 h. The routine MTT assay was performed and the IC 50 (50% inhibiting concentration) of peptides towards different cells were calculated.…”