title: A simple and effective method to synthesize fluorescent nanoparticles using tryptophan and light and their lethal effect against bacteria.
abstract: A simple, environmentally friendly and cost-effective method was used to synthesize silver nanoparticles using tryptophan and light. To prepare the nanoparticles, the following components were used: deionized water, silver nitrate, light and tryptophan. The effects of the tryptophan concentration and light exposure time on the formation of tryptophan silver nanoparticles (Tnnps) were studied. The synthesized Tnnps were characterized using transmission electron microscopy (TEM), absorption and fluorescence spectroscopy and zeta potential measurements. The synthesized Tnnps were nearly spherical, with sizes of approximately 17 nm. In addition, the antibacterial activity of Tnnps was determined by monitoring the growth curves of strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Serratia marcescens, and Enterococcus faecalis using the microdilution test. The Minimum Inhibitory Concentration (MIC) for 4 of 5 tested bacteria was determined to be between 20.0 and 17.5 μg/mL for 48 h and between 22.5 and 20.0 μg/mL for 72 h.
authors.affiliation: Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.
authors.forename: Rafael Jun
authors.initials: RJ
authors.lastname: Tomita
authors.affiliation: Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.
authors.forename: Ricardo Almeida
authors.initials: RA
authors.lastname: de Matos
authors.affiliation: Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil.
authors.forename: Marcelo Afonso
authors.initials: MA
authors.lastname: Vallim
authors.affiliation: Universidade Federal de São Paulo - UNIFESP, São Paulo, Brazil. Electronic address: lccourrol@gmail.com.
authors.forename: Lilia Coronato
authors.initials: LC
authors.lastname: Courrol
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000528:radiation effects; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000528:radiation effects; D055772:Green Chemistry Technology; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000633:toxicity; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D014364:Tryptophan
keywords: Bacteria; MIC; Photoreduction; Silver nanoparticles; Tryptophan