High-power pulsed electrochemiluminescence for optogenetic manipulation of Drosophila larval behaviour

TL;DR

This paper introduces a high-power pulsed electrochemiluminescence device with enhanced stability and brightness, enabling effective optogenetic control of Drosophila larvae and simultaneous behavioral imaging.

Contribution

It presents a novel pulsed operation strategy for ECL devices that significantly increases light output and stability for biomedical optogenetics applications.

Findings

Achieved optical power density over 100 microW/mm2 for thousands of pulses

Extended high-brightness light pulses with minimal power loss

Successfully manipulated Drosophila larval behavior using the device

Abstract

Electrochemiluminescence (ECL) produces light through electrochemical reactions and has shown promise for various analytic applications in biomedicine. However, the use of ECL devices (ECLDs) as light sources has been limited due to insufficient light output and low operational stability. In this study, we present a high-power pulsed operation strategy for ECLDs to address these limitations and demonstrate their effectiveness in optogenetic manipulation. By applying a biphasic voltage sequence with short opposing phases, we achieve intense and efficient ECL through an exciplex-formation reaction pathway. This approach results in an exceptionally high optical power density, exceeding 100 microW/mm2, for several thousand pulses. Balancing the ion concentration by optimizing the voltage waveform further improves device stability. By incorporating multiple optimized pulses into a burst signal separated by short rest periods, extended light pulses of high brightness and with minimal power loss over time were obtained. These strategies were leveraged to elicit a robust optogenetic response in fruit fly (Drosophila melanogaster) larvae expressing the optogenetic effector CsChrimson. The semi-transparent nature of ECLDs facilitates simultaneous imaging of larval behaviour from underneath, through the device. These findings highlight the potential of ECLDs as versatile optical tools in biomedical and neurophotonics research.