High-Spatiotemporal-Resolution Transparent Thermoelectric Temperature Sensor Arrays Reveal Temperature-Dependent Windows for Reversible Photothermal Neuromodulation

Abstract

Photothermal neural stimulation enables optical excitation or inhibition of neural activity depending on the dynamics of localized temperature changes, offering high spatial resolution without genetic modification. However, quantitative analysis of these temperature dynamics remains limited due to the lack of suitable direct sensing technologies, posing a challenge to the safe and controlled application of photothermal neural stimulation techniques. This challenge is addressed by developing transparent thermoelectric temperature sensor arrays with high spatiotemporal resolution, integrated with electrical and optical recording capabilities. These microscale sensors stably and accurately capture rapid temperature increases and decreases, and thermal equilibrium induced by thermo-plasmonic effects at the neural interface, regardless of the environment. The multifunctional platform allows simultaneous electrical and optical monitoring of neural responses during the photothermal stimulation, enabling detailed analysis of the correlation between localized temperature changes and neural activities. a reversible neural inhibition window (1.4-4.5 degrees C) and thresholds for irreversible damage (>6.1 degrees C) are identifyed. Using high temporal-resolution sensing, localized thermo-plasmonic temperature dynamics over tens of milliseconds, and associated neural signal suppression and reactivation are captured. This approach provides unprecedented insight into the interplay between photothermal effects and neural activity, establishing a foundation for precise, temperature-guided neuromodulation therapies and advanced neural circuit research.