# An ultrasound-scanning in vivo light source

## TL;DR

This paper introduces a non-invasive method using ultrasound to generate light deep inside the body for precise biological control.

## Contribution

A novel in vivo light source using ultrasound-scanning mechanoluminescent nanotransducers for dynamic deep-tissue optical interfacing.

## Key findings

- The approach enables programmable light patterning in tissue-mimicking phantoms and animal circulatory systems.
- The system allows dynamic 3D brain targeting and behavioral control in freely moving animals.
- Functionality was validated through electrophysiological recordings and immunostaining in opsin-expressing neurons.

## Abstract

Biological systems operate across distributed regions with fast, localized dynamics, yet existing biointerfaces fail short in providing both high spatiotemporal precision and the ability to dynamically target any region without disturbing surrounding tissue. Here, we present an in vivo deep-tissue light source based on focused ultrasound (FUS) scanning of mechanoluminescent nanotransducers (MLNTs) circulating through the vasculature. We demonstrate the programmability of this approach in tissue-mimicking phantoms and the endogenous circulatory system of animals, where tunable spatial resolution and dynamic light patterning can be achieved. We validate the functionality of the ultrasound-scanning light source in opsin-expressing neurons through electrophysiological recordings and immunostaining. We showcase dynamic three-dimensional brain targeting and temporally resolved behavioral control in freely moving animals via the ultrasound-scanning in vivo light source. This non-invasive deep-tissue light source offers a versatile strategy for body-wide optical interfacing.