jp6b06385_si_001.pdf (626.89 kB)
Effect of Silver Nanoparticles on the Photophysics of Riboflavin: Consequences on the ROS Generation
journal contribution
posted on 2016-09-01, 00:00 authored by María
Belén Rivas Aiello, Juan José Romero, Sonia G. Bertolotti, Mónica C. Gonzalez, Daniel O. MártireMetal-enhanced singlet oxygen, O2(1Δg), generation is a desirable
effect to augment the amount
of O2(1Δg) produced upon irradiation
of organic sensitizers. Herein, we employed pectin for stabilizing
9 nm silver nanoparticles and showed that these particles are able
to form a ground-sate complex with riboflavin (Rf). Pump–probe
transient absorption spectroscopy and laser flash-photolysis experiments
proved that the excited state of the riboflavin–Ag complex
feeds the triplet state of the sensitizer, which results in an enhanced
intersystem crossing process. The higher amounts of riboflavin triplet
states formed in the presence of the nanoparticles result in higher
yields of singlet oxygen and hydrogen peroxide produced in the irradiated
colloidal suspensions. As a result, not only the effect on singlet
oxygen but also the effect on superoxide radical ion should contribute
to a better performance of Riboflavin as a sensitizer applied to the
photodynamic therapy of tumors.