# OPTRACE: Optical Imaging–Guided Transplantation and Tracking of Cells in the Mouse Brain

## TL;DR

OPTRACE is a new optical system that improves the precision of cell transplantation in the brain and tracks cells over time, helping to advance regenerative therapies.

## Contribution

OPTRACE introduces a two-step optical framework combining real-time imaging and predictive models for precise cell delivery and tracking.

## Key findings

- OPTRACE uses translucent glass pipettes and predictive models to optimize cell delivery and minimize hypoperfusion.
- Multicolor labeling and two-photon microscopy enable longitudinal tracking of transplanted cells and host responses.
- The system provides micrometer precision and quantitative insights into cell behavior during and after transplantation.

## Abstract

Intracerebral cell transplantation holds promise for treating stroke and neurological disorders, yet challenges in precise delivery and post‐engraftment monitoring impede progress. This work introduces OPTRACE (OPtical imaging‐guided Transplantation and tRAcking of CElls), a two‐step optical framework integrating real‐time visualization during transplantation with longitudinal post‐transplantation in vivo cell tracking. Leveraging cost‐effective translucent glass micropipettes and two innovative predictive mathematical modeling—the retention–depth model (predicts retained fraction versus injection depth) and the hypoperfusion–volume model (predicts hypoperfused fraction versus graft volume)—that this work fits to data (depth–retention R2 = 0.91; volume–growth R2 = 0.78)—OPTRACE optimizes delivery parameters to maximize engraftment and minimize hypoxia. A novel pulse‐elevation injection technique further enhances the precision of superficial cortical retention. Following transplantation, multicolor labeling combined with two‐photon fluorescence microscopy permits longitudinal single‐cell tracking, revealing host microglial responses, and altered neuronal calcium signaling at the graft interface. OPTRACE provides micrometer precision, longitudinal dynamics and quantitative insights of cells during and after transplantation, accelerating mechanistic understanding and therapeutic development for regenerative cell therapies.

OPTRACE establishes an optical, two‐step platform for intracerebral cell therapy. Transparent glass pipettes enable real‐time, image‐guided delivery, while multiplex genetic labeling with two‐photon and bioluminescence readouts supports longitudinal single‐cell tracking and host–graft dynamics. Predictive models tune depth and volume to maximize retention and limit hypoperfusion, unifying preparation, transplantation, and post‐engraftment analysis in an accessible workflow.