# Label-Free Imaging of Composite Hyaluronic Acid Hydrogels in Regenerative Medicine

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $367,698

## Abstract

Hydrogel scaffolds are increasingly being used as tissue-mimicking materials and as vehicles to improve
transplanted stem cell retention and survival. We have recently developed a new chemical exchange
saturation transfer (CEST) magnetic resonance imaging (MRI) method that is able to probe the in vivo stability
and gelatin decomposition of implanted composite hyaluronic acid (HA) hydrogels in a “label-free” fashion.
Compared to naked cells, we found that transplanted neural stem cells showed improved survival when
hydrogel scaffolding was applied. A major question that remains is the optimal mechanical properties of the
hydrogel, and how this relates to cell survival. At the one hand, for initial structural support, the gels should not
decompose too fast, but at the other hand they should at some point decompose to allow transplanted cells to
grow out and integrate with the surrounding host tissue. Our aim is to synthesize a range of composite near-
infrared (NIR)-HA hydrogels with different compositions and stabilities, to image their stability properties in
vivo, and to correlate the CEST/NIR optical imaging findings with cell survival as assessed using
bioluminescent imaging (BLI) as conventional readout. Using supercharged green fluorescent protein (sGFP)
as a new CEST MRI bimodal reporter gene, we will also investigate whether or not CEST MRI is able to probe
in vivo cell survival simultaneously. We have chosen to apply this approach to transplantation of glial-restricted
precursor cells (GRPs) in a transgenic amyotropic lateral sclerosis (ALS) mouse model, as we have found that
transplanted naked cells without hydrogel scaffolding survive poorly in the hostile ALS tissue environment.

## Key facts

- **NIH application ID:** 9895784
- **Project number:** 5R01EB023647-04
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Jeff W. Bulte
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $367,698
- **Award type:** 5
- **Project period:** 2017-06-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9895784

## Citation

> US National Institutes of Health, RePORTER application 9895784, Label-Free Imaging of Composite Hyaluronic Acid Hydrogels in Regenerative Medicine (5R01EB023647-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9895784. Licensed CC0.

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