Riboflavin-Mediated Photooxidation of Gold Nanoparticles and Its Effect on the Inactivation of Bacteria.
María Belén Rivas AielloFiorela GhiliniJoaquín E Martínez PorcelLisandro J GiovanettiPatricia L SchilardiDaniel O MártirePublished in: Langmuir : the ACS journal of surfaces and colloids (2020)
Photodynamic inactivation (PDI) of microorganisms, based on the ability of photosensitizers to produce reactive oxygen species (ROS) under adequate irradiation, emerges as a promising technique to face the increasing bacterial resistance to conventional antimicrobials. In this work, we analyze the combined action of Riboflavin (Rf) and pectin-coated gold nanoparticles (PecAuNP) on Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) as suitable PDI strategy. We demonstrate that gold ions can be generated upon Rf-photosensitized oxidation of PecAuNP. Transient absorption spectroscopy shows that the Rf cationic radical can accept an electron from the nanoparticles to yield Au(I) ions, which in aqueous medium is disproportionate to yield Au0 and Au(III). Microbiological assays showed that the presence of PecAuNP enhanced the antibacterial activity of photoirradiated Rf toward S. aureus and P. aeruginosa, in line with the well-known antibacterial activity of gold ions. Moreover, the irradiation of Rf solutions containing about 100 μM PecAuNP enabled the solutions to be bactericidal against both bacteria.
Keyphrases
- gold nanoparticles
- reduced graphene oxide
- reactive oxygen species
- sensitive detection
- pseudomonas aeruginosa
- quantum dots
- staphylococcus aureus
- silver nanoparticles
- biofilm formation
- cystic fibrosis
- photodynamic therapy
- cell death
- aqueous solution
- escherichia coli
- single molecule
- oxidative stress
- cerebral ischemia
- nitric oxide
- acinetobacter baumannii
- blood brain barrier
- subarachnoid hemorrhage
- ionic liquid
- cancer therapy
- radiation therapy
- solid state