Shedding Light on Living Cells

Abstract

An overview of the optical methods available to modulate the cellular activity in cell cultures and biological tissues is presented, with a focus on the use of exogenous functional materials that absorb electromagnetic radiation and transduce it into a secondary stimulus for cell excitation, with high temporal and spatial resolution. Both organic and inorganic materials are critically evaluated, for in vitro and in vivo applications. Finally, as a direct practical application of optical-stimulation techniques, the most recent results in the realization of artificial visual implants are discussed.

Photocatalytic Activity of Polymer Nanoparticles Modulates Intracellular Calcium Dynamics and Reactive Oxygen Species in HEK-293 Cells

“…The direct heating of water with a near IR laser radiation (Shapiro et al, 2012), the use of organic and inorganic devices such as photocapacitors and photodetectors (Goda and Colicos, 2006; Farah et al, 2013; Antognazza et al, 2015; Martino et al, 2015; Feyen et al, 2016; Maya-Vetencourt et al, 2017), and the introduction of conducting or semiconducting nanoparticles (Colombo et al, 2016) are among reported strategies. The latter approach is quite interesting, because it allows an easy sensitization of the target tissue and, in principle, it can select specific sites within cell sub-compartments.…”

The Photophysics of Polythiophene Nanoparticles for Biological Applications

“…The presence of a π‐conjugated carbon skeleton, much akin to many biomolecules, makes conjugated organic polymers potentially viable materials for biological applications . They have been already successfully implemented in electrolyte gated transistors, electrodes, ionic devices, sensors, and optical interfaces . In particular, thin films of poly(3‐hexylthiophene) (P3HT) have been employed as optical interfaces to trigger cellular activity upon photoexcitation .…”

Photovoltaic stimulation efficiently evokes network-mediated activity of retinal ganglion cells

“…Though, inner and ganglion retinal neurons are known to be temporarily spared by the degeneration process 33 and to be electrically excitable to convey artificial visual inputs to the lateral geniculate nucleus [4][5][6][7]. Several 34 retinal prostheses have been developed in the past decade and demonstrated promising results to restore an 35 elementary form of vision, including discrimination of high-contrast gratings, reading of large prints, and 36 spatial orientation [7][8][9][10][11][12][13]. Nonetheless, current clinical implants provide limited visual acuity, and the sight 37 quality is still far away from being adequate in daily life [14].…”