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Light-up bioprobe with aggregation-induced emission characteristics for real-time apoptosis imaging in target cancer
Dan Ding1, Jing Liang, Haibin Shi
1Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore. cheliub@nus.edu.sg.
Abstract:
Specific bioprobes that are capable of real-time and targeted monitoring and imaging of cancer cell apoptosis are highly desirable for cancer diagnosis and the evaluation of cancer therapy efficacy. In this work, an asymmetric fluorescent light-up bioprobe with aggregation-induced emission (AIE) characteristics was designed and synthesized by the conjugation of two different hydrophilic peptides, caspase-specific Asp-Glu-Val-Asp (DEVD) and cyclic Arg-Gly-Asp (cRGD), onto a typical AIE luminogen of a tetraphenylsilole (TPS) unit. The asymmetric probe is almost non-emissive in aqueous solution and its fluorescence is significantly switched on in the presence of caspase-3. The fluorescence turn-on is due to the cleavage of the DEVD moiety by caspase-3, and the aggregation of released TPS-cRGD residues, which restricts the intramolecular rotations of TPS phenyl rings and populates the radiative decay channels. Application of the asymmetric light-up probe for real-time targeted imaging of cancer cell apoptosis is successfully demonstrated using integrin αvβ3 receptor overexpressing U87MG human glioblastoma cells as an example. The probe shows specific targeting capability to U87MG cancer cells by virtue of the efficient binding between cRGD and integrin αvβ3 receptors and is able to real-time monitor and image cancer cell apoptosis in a specific and sensitive manner.
Insights
A novel fluorescent light-up bioprobe detects cancer cell apoptosis in real-time. This probe, utilizing aggregation-induced emission, specifically targets cancer cells by monitoring caspase-3 activity for improved diagnosis and therapy evaluation.
Area of Science:
- Biomedical Engineering
- Chemical Biology
- Molecular Imaging
Background:
- Targeted, real-time monitoring of cancer cell apoptosis is crucial for diagnosis and therapy assessment.
- Existing bioprobes often lack specificity or real-time imaging capabilities for apoptosis detection.
Purpose of the Study:
- To design and synthesize an asymmetric fluorescent light-up bioprobe with aggregation-induced emission (AIE) characteristics.
- To enable real-time and targeted imaging of cancer cell apoptosis.
- To evaluate the probe's specificity and sensitivity in cancer cells.
Main Methods:
- Conjugation of caspase-specific Asp-Glu-Val-Asp (DEVD) and cyclic Arg-Gly-Asp (cRGD) peptides to a tetraphenylsilole (TPS) AIE luminogen.
- Investigation of the probe's fluorescence response to caspase-3 activity in aqueous solutions.
- Demonstration of real-time apoptosis imaging in U87MG human glioblastoma cells overexpressing integrin αvβ3 receptors.
Main Results:
- The synthesized asymmetric probe exhibits minimal fluorescence in aqueous solution, acting as a "light-up" system.
- Caspase-3 activation triggers probe cleavage, leading to aggregation and significant fluorescence enhancement.
- The probe specifically targets U87MG cancer cells via cRGD binding to integrin αvβ3 receptors.
- Successful real-time, specific, and sensitive imaging of cancer cell apoptosis was achieved.
Conclusions:
- The developed asymmetric AIE bioprobe offers a sensitive and specific platform for real-time monitoring and imaging of cancer cell apoptosis.
- This probe holds potential for advancing cancer diagnosis and evaluating the efficacy of cancer therapies.
