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Updated: Jun 23, 2025
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Published on: June 6, 2022
Improved glucose detection limit based on phosphorescence from protected metalloporphyrin triplet state
Lixin Zang1, Jingying Wang1, Xueying Yang1
1College of Chemistry, Chemical Engineering and Materials Science, Shandong Provincial Engineering and Technical Center of Light Manipulations, Shandong Provincial Key Laboratory of Optics and Photonic Device, School of Physics and Electronics, Shandong Normal University, Ji'nan, 250014, China.
A new optical indicator enhances phosphorescence for sensitive, non-invasive glucose monitoring in tears. This method achieves a low detection limit and fast response, improving glucose sensing capabilities.
Area of Science:
- Biomedical Optics
- Chemical Sensors
- Analytical Chemistry
Background:
- Non-invasive glucose monitoring in tears requires sensitive optical indicators.
- Palladium hematoporphyrin monomethyl ether (Pd-HMME) shows increased phosphorescence with glucose consumption but has a high detection limit (800 μM) due to oxygen quenching.
Purpose of the Study:
- To improve the glucose detection limit of Pd-HMME phosphorescence-based methods.
- To develop a sensitive, selective, and fast optical indicator for low-concentration glucose sensing.
Main Methods:
- Introduction of a triplet protector, imidazole, to enhance Pd-HMME phosphorescence under ambient oxygen.
- Measurement of phosphorescence intensity changes in response to varying glucose concentrations.
Main Results:
- Strong phosphorescence observed under ambient oxygen conditions.
- Detectable phosphorescence enhancement at glucose concentrations below 200 μM.
- Linear correlation (R² = 99.9%) between phosphorescence intensity and glucose concentration from 30-727 μM, with a detection limit of ~10 μM.
- Fast response time (~90 s) and excellent glucose selectivity.
Conclusions:
- The developed optical indicator shows potential for fast, selective, and reliable low-concentration glucose sensing.
- Imidazole addition significantly improves Pd-HMME performance for glucose detection.
