# Expanding the Redox Biology Toolbox

> **NIH NIH R43** · CHEMICAL BIOLOGY PROBES LLC · 2020 · $150,000

## Abstract

Abstract
 Glutathione (GSH) is the most abundant non-protein thiol in eukaryotic cells. GSH maintains cellular redox
homeostasis and is involved in numerous biological processes. These important functions are dynamically
regulated by the intracellular concentration and distribution of GSH. Currently, the concentration of intracellular
GSH is derived from either cell lysates or GSH-S-transferase (GST) dependent probes. These approaches,
however, cannot provide information about the real-time dynamics of GSH concentration changes. We reported
the first reversible reaction-based GSH probe (ThiolQuant Green) that can perform single-point quantification of
GSH levels in living cells and developed the 2nd generation GSH probe—RealThiol (RT)—that allows real-time
monitoring of GSH dynamics in living cells. We filed a patent on these GSH probes (WO2016025382) and have
shared the RealThiol probe with >70 redox biology labs around the world. Additionally, the Division of Cancer
Treatment & Diagnosis Laboratory Support at National Cancer Institute (NCI) is interested in applying our GSH
probes in their drug screening assays and requested gram quantity of RT probes. The overarching goal for this
Phase I project is to develop probes that can monitor the dynamics of the concentration change of GSH in real-
time with subcellular specificity and to provide a complete toolset to study GSH-related redox biology. For Phase
II commercialization, we will focus on both basic and clinical research. We will develop assay kits for GSH-related
biology, such as ferroptosis. We will also apply our GSH probes in clinical samples to help identify patients with
drug/radiation-resistant tumors.

## Key facts

- **NIH application ID:** 10009815
- **Project number:** 1R43GM137665-01
- **Recipient organization:** CHEMICAL BIOLOGY PROBES LLC
- **Principal Investigator:** Xiaoli Qi
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $150,000
- **Award type:** 1
- **Project period:** 2020-07-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10009815

## Citation

> US National Institutes of Health, RePORTER application 10009815, Expanding the Redox Biology Toolbox (1R43GM137665-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10009815. Licensed CC0.

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