Related Experiment Video
Updated: Sep 4, 2025
Non-invasive In Vivo Fluorescence Optical Imaging of Inflammatory MMP Activity Using an Activatable Fluorescent Imaging Agent
Published on: May 8, 2017
Polypeptide induced perylene probe excimer formation and its application in the noncovalent ratiometric detection of
Xiaoyu Gou1, Muhammad Azhar Hayat Nawaz2,3,4, Chaoyi Liu2
1School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun 130022, China.
Abstract:
Matrix metalloproteinases (MMPs) are important biomarkers for a number of diseases. Thus, the precise determination of MMP activity is of crucial importance. Herein, we report a ratiometric fluorescence method for the sensitive and selective sensing of MMP activity. A number of positively charged MMP substrates (polypeptides) were designed and prepared. These polypeptides could induce aggregation of a negatively charged perylene diimide derivative (PC1). As a result, excimer fluorescence of PC1 was observed. Addition of the corresponding MMP resulted in cleavage of the polypeptide chain and dis-aggregation of PC1, which led to turning on of the PC1 monomer fluorescence. Based on the ratio of the monomer (545 nm, IM) and the excimer (680 nm, IM) fluorescence intensity changes, a ratiometric method I545/I680) was established to detect MMP activity. The enzymatic activity of a number of MMPs (MMP-1, 2, 3, 7, 9 and 13) could be determined with a limit of detection of 4.8, 2.2, 16, 6.0, 1.7 and 5.5 ng mL-1, respectively. Using MMP-2 and MMP-9 as examples, flavonoid herbal extracts as potential inhibitors were studied. It was observed that mangiferin, apigenin, quercetin and isoliquiritigenin had significant inhibiting effects on the enzyme activity. And these herbal extracts also inhibited tumor cell metastasis. Moreover, the developed strategy was also employed to determine the concentration of MMP-9 in human saliva samples. Since the method relies on only noncovalent interactions between the polypeptide and PC1, no covalent labeling of fluorescence dye on the polypeptide substrate is required, and the method is thus simple, broad-spectrum inexpensive and effective. It has the potential to be developed into a clinical test kit.
Insights
A new ratiometric fluorescence method accurately detects matrix metalloproteinase (MMP) activity using polypeptide substrates and a perylene diimide derivative. This approach offers a simple, sensitive, and broad-spectrum tool for disease biomarker detection and potential clinical applications.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Molecular Biology
Background:
- Matrix metalloproteinases (MMPs) are crucial biomarkers implicated in various diseases.
- Accurate determination of MMP activity is essential for disease diagnosis and monitoring.
- Existing methods for MMP detection can be complex or lack sensitivity.
Purpose of the Study:
- To develop a sensitive and selective ratiometric fluorescence method for detecting MMP activity.
- To establish a simple, cost-effective, and broad-spectrum assay for MMPs.
- To investigate the inhibitory effects of flavonoid herbal extracts on MMPs and their impact on tumor cell metastasis.
Main Methods:
- Designed and synthesized positively charged polypeptide substrates for MMPs.
- Utilized a negatively charged perylene diimide derivative (PC1) that aggregates in the presence of polypeptides, leading to excimer fluorescence.
- Developed a ratiometric fluorescence assay based on the ratio of monomer (545 nm) to excimer (680 nm) emission changes upon MMP-induced substrate cleavage and PC1 disaggregation.
Main Results:
- The ratiometric method achieved sensitive detection of various MMPs (MMP-1, 2, 3, 7, 9, 13) with low limits of detection (e.g., 1.7 ng mL⁻¹ for MMP-9).
- Flavonoid herbal extracts (mangiferin, apigenin, quercetin, isoliquiritigenin) demonstrated significant inhibition of MMP-2 and MMP-9 activity and suppressed tumor cell metastasis.
- The method was successfully applied to quantify MMP-9 in human saliva samples, demonstrating its clinical relevance.
Conclusions:
- The developed ratiometric fluorescence assay provides a simple, sensitive, selective, and cost-effective platform for MMP activity detection.
- The assay does not require covalent labeling, relying on noncovalent interactions, making it broadly applicable.
- This method holds significant potential for development into a clinical diagnostic tool for MMP-related diseases and for evaluating natural product inhibitors.
