The light-oxygen effect in biological cells enhanced by highly localized surface plasmon-polaritons

Anna Khokhlova,Edik Rafailov,Yury Saenko,Sergei Sokolovski,Dmitrii Stoliarov,Andrei Fotiadi,Vyacheslav Svetukhin,Igor Zolotovskii,Evgenia Pogodina,Vladimir Sibirny

doi:10.1038/s41598-019-54905-5

Abstract

Here at the first time we suggested that the surface plasmon-polariton phenomenon which it is well described in metallic nanostructures could also be used for explanation of the unexpectedly strong oxidative effects of the low-intensity laser irradiation in living matters (cells, tissues, organism). We demonstrated that the narrow-band laser emitting at 1265 nm could generate significant amount of the reactive oxygen species (ROS) in both HCT116 and CHO-K1 cell cultures. Such cellular ROS effects could be explained through the generation of highly localized plasmon-polaritons on the surface of mitochondrial crista. Our experimental conditions, the low-intensity irradiation, the narrow spectrum band (<4 nm) of the laser and comparably small size bio-structures (~10 μm) were shown to be sufficient for the plasmon-polariton generation and strong laser field confinement enabling the oxidative stress observed.

Highlights

At the first time we suggested that the surface plasmon-polariton phenomenon which it is well described in metallic nanostructures could be used for explanation of the unexpectedly strong oxidative effects of the low-intensity laser irradiation in living matters
In order to explain the observed effect, we proposed a model that involves surface plasmon polaritons which are presumably generated on the surface of the inner mitochondrial membrane
In this work we reveal the singlet oxygen generation induced by the laser radiation in individual CHO-K1 and HCT116 cells, which demonstrated narrow-band resonant sensitivity at 1265 nm

Summary

Introduction

At the first time we suggested that the surface plasmon-polariton phenomenon which it is well described in metallic nanostructures could be used for explanation of the unexpectedly strong oxidative effects of the low-intensity laser irradiation in living matters (cells, tissues, organism). We demonstrated that the narrow-band laser emitting at 1265 nm could generate significant amount of the reactive oxygen species (ROS) in both HCT116 and CHO-K1 cell cultures Such cellular ROS effects could be explained through the generation of highly localized plasmon-polaritons on the surface of mitochondrial crista. With all advantages of this approach, non-invasiveness, precisive control of the irradiation dose it has significant disadvantages, i.e. intrinsic and photo- toxicity of the photosensitizers Another approach where light irradiation is widely used at comparably low intensities is photobiomodulation (PBM) which is very promising laser therapy that is based on the laser-induced intracellular ROS generation[6,7,8,9]. These values are at least 5 orders of magnitude lower than the absorption cross-section in the near-IR absorption band (including 1260–1270 nm) reported a typical photosensitizer (e.g. porphyrins), σss ≈ 10−18–10−19 cm[2 24]

Discussion

Conclusion