Issue 1, 2024

The light-dependent pseudo-capacitive charging of conjugated polymer nanoparticles coupled with the depolarization of the neuronal membrane

Abstract

The mechanism underlying visual restoration in blind animal models of retinitis pigmentosa using a liquid retina prosthesis based on semiconductive polymeric nanoparticles is still being debated. Through the application of mathematical models and specific experiments, we developed a coherent understanding of abiotic/biotic coupling, capturing the essential mechanism of photostimulation responsible for nanoparticle-induced retina activation. Our modeling is based on the solution of drift-diffusion and Poisson–Nernst–Planck models in the multi-physics neuron-cleft-nanoparticle-extracellular space domain, accounting for the electro-chemical motion of all the relevant species following photoexcitation. Modeling was coupled with electron microscopy to estimate the size of the neuron-nanoparticle cleft and electrophysiology on retina explants acutely or chronically injected with nanoparticles. Overall, we present a consistent picture of electrostatic depolarization of the bipolar cell driven by the pseudo-capacitive charging of the nanoparticle. We demonstrate that the highly resistive cleft composition, due to filling by adhesion/extracellular matrix proteins, is a crucial ingredient for establishing functional electrostatic coupling. Additionally, we show that the photo-chemical generation of reactive oxygen species (ROS) becomes relevant only at very high light intensities, far exceeding the physiological ones, in agreement with the lack of phototoxicity shown in vivo.

Graphical abstract: The light-dependent pseudo-capacitive charging of conjugated polymer nanoparticles coupled with the depolarization of the neuronal membrane

Supplementary files

Article information

Article type
Communication
Submitted
10 sep 2023
Accepted
20 nov 2023
First published
25 nov 2023
This article is Open Access
Creative Commons BY-NC license

Phys. Chem. Chem. Phys., 2024,26, 47-56

The light-dependent pseudo-capacitive charging of conjugated polymer nanoparticles coupled with the depolarization of the neuronal membrane

G. Chiaravalli, T. Ravasenga, E. Colombo, Jasnoor, S. Francia, S. Di Marco, R. Sacco, G. Pertile, F. Benfenati and G. Lanzani, Phys. Chem. Chem. Phys., 2024, 26, 47 DOI: 10.1039/D3CP04386J

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