Development of a calcium phosphate nanocomposite for fast fluorogenic detection of bacteria

A Galactosidase-Activatable Fluorescent Probe for Detection of Bacteria Based on BODIPY

Pathogenic E. coli infection is one of the most widespread foodborne diseases, so the development of sensitive, reliable and easy operating detection tests is a key issue for food safety. Identifying bacteria with a fluorescent medium is more sensitive and faster than using chromogenic media. This study designed and synthesized a β-galactosidase-activatable fluorescent probe BOD-Gal for the sensitive detection of E. coli. It employed a biocompatible and photostable 4,4-difluoro-3a,4a-diaza-s-indancene (BODIPY) as the fluorophore to form a β-O-glycosidic bond with galactose, allowing the BOD-Gal to show significant on-off fluorescent signals for in vitro and in vivo bacterial detection. This work shows the potential for the use of a BODIPY based enzyme substrate for pathogen detection.

Biofabrication of streptomycin-conjugated calcium phosphate nanoparticles using red ginseng extract and investigation of their antibacterial potential

Conjugation of nanoparticles (NPs) with antibiotics for treating multidrug resistant pathogens has been enormously studied now a days. In the current investigation, calcium phosphate (CaP) NPs were produced by co-precipitation using red ginseng extract as the reducing agent and were conjugated to the antibiotic streptomycin to form streptomycin-conjugated NPs (CPG-S NPs). The CPG-S NPs antibacterial activity was evaluated in this study against eight plant and five foodborne pathogenic bacteria. The synthesized CPG-S NPs were characterized by UV-VIS spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray powder diffraction, and thermogravimetric and differential thermogravimetric analysis. CPG-S NPs exhibited promising antibacterial activity against all eight plant pathogenic bacteria and three of the five foodborne pathogenic bacteria tested; the diameter of inhibition zones ranged between 9.74-16.95 mm and 9.82-15.84 mm, respectively. CPG-S NPs displayed 50-100 μg/mL of minimum inhibitory concentration and 100 μg/mL of minimum bactericidal concentration against the plant and foodborne pathogenic bacterial strains, respectively. Furthermore, the SEM image of bacteria treated with CPG-S NPs displayed cells with a ruptured cell wall and fewer cells compared to the SEM image of untreated control bacteria displaying uniform and intact cells. SEM confirmed that CPG-S NPs degraded the bacterial cell wall and membrane resulting in lysed bacterial cells. In conclusion, the results suggest that CPG-S NPs could be effectively utilized in formulating drugs to treat bacterial plant or dental diseases and in manufacturing dental products such as toothpaste, mouthwashes, and artificial teeth.

Novel Pyrimidine Tagged Silver Nanoparticle Based Fluorescent Immunoassay for the Detection of Pseudomonas aeruginosa

A simple pyrimidine-based fluorescent probe (R)-4-(anthracen-9-yl)-6- (naphthalen-1-yl)-1,6-dihydropyrimidine-2-amine (ANDPA) was synthesized through the greener one pot reaction and characterized by IR, NMR, and ESI-Mass. Glucose stabilized silver nanoparticles (Glu-AgNPs) were also synthesized and characterized using UV, IR, XRD, SEM, and TEM. When ANDPA was tagged with Glu-AgNPs, the fluorescent intensity of ANDPA decreased drastically. When the monoclonal antibody (Ab) [immunoglobulin G (IgG)] of Pseudomonas aeruginosa (PA) was attached with ANDPA/Glu-AgNPs, the original intensity of the probe was recovered with minimal enhancement at 446 nm. On further attachment of PA with ANDPA/Glu-AgNPs/PA, the fluorescence intensity of the probe was enhanced obviously at 446 nm with red shift. This phenomenon was further supported by SEM and TEM. The linear range of detection is from 8 to 10^-1 CFU/mL, and LOD is 1.5 CFU/mL. The immunosensor was successfully demonstrated to detect Pseudomonas aeruginosa in water, soil, and food products like milk, sugar cane, and orange juices.

Pyrimidine-based functional fluorescent organic nanoparticle probe for detection of Pseudomonas aeruginosa

Organic nanoparticles are developed for the sensing of Pseudomonas aeruginosa.