Related Experiment Video
Updated: Sep 29, 2025
Nanosensors to Detect Protease Activity In Vivo for Noninvasive Diagnostics
Published on: July 16, 2018
A ratiometric fluorescent probe based on peptide modified MnFe2O4 nanoparticles for matrix metalloproteinase-7
Hongda Chen1,2, Hua Zhang1, Zhenxin Wang1,2
1State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China. zhanghua@ciac.ac.cn.
Abstract:
Abnormal expression of matrix metalloproteinases plays an important role in tumor invasion and metastasis. In this report, a peptide modified MnFe2O4 ratiometric fluorescent nanoprobe is developed for noninvasively visualizing the distribution of matrix metalloproteinase-7 (MMP-7) in vitro and in vivo. A fluorescein isothiocyanate (FITC) modified peptide containing the specific motif VPLSLTMG for MMP-7 cleavage was conjugated with MnFe2O4 nanoparticles (NPs) to establish a Förster resonance energy transfer (FRET) system for sensing the protease. The rhodamine B (RhB) modified targeting peptide immobilized on the nanoparticle surface was not only used as an internal reference for forming a ratiometric fluorescence system together with the FITC dye, but also used for enhancing the tumor targeting ability. The tumor accumulation amount of the as-developed ratiometric fluorescent probe (termed MnFe2O4-pep-dyes) can be measured by T2-weighted magnetic resonance (T2-weighted MR) imaging because MnFe2O4 NPs display an excellent T2-weighted MR contrast ability. In the presence of MMP-7, FITC detached from the MnFe2O4 surface resulting in the recovery of FITC fluorescence, while no obvious change of the RhB fluorescence was observed. The recovery ratio of FITC to RhB fluorescence intensity is linearly dependent on the MMP-7 concentration within the range of 0.1 to 15 nM in buffer and 5 × 102 to 1 × 104 cells in cell lysates with a limit of detection of 0.1 nM and 436 cells, respectively. MnFe2O4-pep-dyes was further applied to spatially observe MMP-7 expression in a tumor-bearing mouse by in vivo fluorescence imaging with external magnetic field assistance for demonstrating its practicability.
Insights
A novel ratiometric fluorescent nanoprobe using MnFe2O4 nanoparticles visualizes matrix metalloproteinase-7 (MMP-7) activity in vitro and in vivo. This probe enables noninvasive detection of MMP-7, crucial for understanding tumor invasion and metastasis.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Molecular Imaging
Background:
- Abnormal matrix metalloproteinase (MMP) expression is critical in tumor invasion and metastasis.
- Matrix metalloproteinase-7 (MMP-7) is a key enzyme implicated in cancer progression.
- Noninvasive imaging methods are needed to visualize MMP activity in biological systems.
Purpose of the Study:
- To develop a peptide-modified MnFe2O4 ratiometric fluorescent nanoprobe for MMP-7 detection.
- To enable noninvasive visualization of MMP-7 distribution in vitro and in vivo.
- To utilize the probe for assessing tumor targeting and MMP-7 expression in a mouse model.
Main Methods:
- Conjugation of fluorescein isothiocyanate (FITC)-labeled MMP-7-specific peptide to MnFe2O4 nanoparticles (NPs).
- Incorporation of a rhodamine B (RhB)-labeled targeting peptide for ratiometric fluorescence and tumor targeting.
- Utilizing Förster resonance energy transfer (FRET) between FITC and RhB for MMP-7 sensing.
- Employing T2-weighted magnetic resonance (T2-weighted MR) imaging for NP accumulation assessment.
Main Results:
- The developed MnFe2O4-pep-dyes probe exhibited ratiometric fluorescence response to MMP-7.
- FITC fluorescence recovery was observed upon MMP-7 cleavage, linearly correlated with enzyme concentration (0.1–15 nM).
- The probe demonstrated a detection limit of 0.1 nM in buffer and 436 cells in lysates.
- In vivo fluorescence imaging in tumor-bearing mice showed spatial MMP-7 expression, aided by external magnetic fields.
Conclusions:
- The MnFe2O4-pep-dyes nanoprobe is a sensitive and specific tool for ratiometric detection of MMP-7.
- The probe allows for noninvasive visualization of MMP-7 activity in vitro and in vivo.
- This technology holds potential for advancing cancer diagnostics and therapeutic monitoring.
