# Nanotracer Development to Track Stem Cell Therapy

> **NIH NIH R01** · UNIVERSITY OF TEXAS AT AUSTIN · 2020 · $418,430

## Abstract

Project Summary
 Peripheral artery disease (PAD) is a form of cardiovascular disease that can reduce blood flow in
the lower limbs ultimately resulting in the potential for loss of limb. Early clinical trials in patients with PAD
resulting in critical limb ischemia have demonstrated the safety of autologous stem cell therapies with
modest improvements in reperfusion and limb salvage. While stem cell therapies may therefore
represent a realistic alternative to conventional revascularization therapies, a number of challenges
remain which limit large-scale clinical trials and widespread use. Outcomes with respect to clinical
efficacy have been less than ideal and are largely attributed to the well-documented cell loss following
delivery. The overwhelming majority (>90 %) of cells do not survive implantation after 1-2 weeks.
 We have described that a degradable hydrogel matrix can improve stem cell-mediated muscle
function recovery following ischemic injury. Our data suggested that one mechanism for improved
recovery was the increased number of cells that were maintained at the site of injury and their beneficial
effects on the host response. Central to our understanding is the necessity of being able to track stem
cells and the infiltrating inflammatory cells, particularly macrophages. Major challenges to the
development of clinically applied stem cell therapy remains the lack of technologies for stem cell tracking,
methods for the improvement of cell viability and strategies to understand the stem cell-mediated host
response. Therefore, the overall goal of the current proposal is to understand the role of delivered stem
cells and the mechanisms of repair in vivo using nanotracer-enhanced, high-resolution combined
ultrasound and photoacoustic (US/PA) imaging. A secondary goal is to be able to quantify the role of
recruited macrophages in a model system in which we are able to correlate imaging quantification with
quantitative measures of muscle function.
 We propose here to utilize plasmonic gold nanoshells as nanotracers, due to their excellent
biocompatibility, as well as tunable, strong optical absorption properties. In contrast with other imaging
techniques, combined US/PA imaging can visualize and quantify cell delivery and function over a broad
range of timescales, spatial resolutions and imaging depths. High-resolution imaging of tissues is
possible as well as visualization in 3D. The combination of nanotracers with US/PA imaging results in a
unique approach that will allow us to answer fundamental questions regarding MSC involvement in
muscle repair as well as validate a clinically translatable solution for tissue regeneration. We propose to
develop this single system in a mouse model of hindlimb ischemia in which we are able to quantify
muscle function, thereby allowing correlation with tissue regeneration.

## Key facts

- **NIH application ID:** 9922903
- **Project number:** 5R01EB015007-08
- **Recipient organization:** UNIVERSITY OF TEXAS AT AUSTIN
- **Principal Investigator:** Laura J Suggs
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $418,430
- **Award type:** 5
- **Project period:** 2012-05-01 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9922903

## Citation

> US National Institutes of Health, RePORTER application 9922903, Nanotracer Development to Track Stem Cell Therapy (5R01EB015007-08). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9922903. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*