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Updated: Aug 11, 2025
Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy
Published on: April 25, 2021
Novel Aggregation-Induced Emission Fluorescent Molecule for Platinum(IV) Ion-Selective Recognition and Imaging of
Xuerong Song1, Wanmeng Li1, Jianing Xu1
1Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun130021, China.
Abstract:
The loading, delivery, and release of Pt(IV) precursors in living organisms are important aspects of exploring the development of platinum drugs. In recent years, the biological application of the fluorescent sensors to platinum drugs has been insufficient to meet the study of Pt(IV) precursors. It is urgent to design and develop a biocompatible, multifunctional fluorescent sensor for the study of loading, transport, and release of Pt(IV) ions. Herein, we report a fluorescent molecule (E)-6-(diethylamino)-N'-(4-(diphenylamino) benzylidene)-2-oxo-2H-chromene-3 carbohydrazide (CHTPA). CHTPA has good sensitivity and selectivity to Pt(IV) when the water content is 5%, and significant increase of the fluorescence emission intensity of CHTPA is observed with Pt(IV) concentration. The sensing mechanism is attributed to photo-induced electron transfer, which is verified by X-ray absorption near edge spectroscopy spectra, UV-vis absorption spectroscopy, 1H NMR spectra, and Fourier transform infrared spectra. Furthermore, the CHTPA-Pt(IV) complex is able to release Pt(IV) in aqueous solution, and the green fluorescence of CHTPA based on the aggregation-induced emission effect can be observed. Inspired by these, the amphiphilic block copolymer poly(ethyloxide)-block-polystyrene (PEO-b-PS) is used to prepare the nonconjugated polymer dots (Pdots). The experimental results show that Pdots can effectively slow down the release speed of Pt(IV) in aqueous solution and it has a great monodispersity in aqueous solution. Meanwhile, Pdots show low cytotoxicity, and this is favorable for intracellular applications. The investigation of cellular imaging indicates that these Pdots can act as a carrier to deliver Pt(IV) into MCF-7 cells for visualized delivery and sustained release of platinum(IV) ions. Therefore, this study provides a new avenue to design and develop a biocompatible multifunctional fluorescent sensor for studying the loading, delivery, and release of Pt(IV) in cells.
Insights
Researchers developed a new fluorescent sensor, CHTPA, for tracking platinum(IV) drug delivery. Polymer dots (Pdots) were used to control the release of platinum(IV) in cells, enabling visualized intracellular delivery.
Area of Science:
- Biomedical Engineering
- Materials Science
- Analytical Chemistry
Background:
- Platinum(IV) precursors are crucial for developing new platinum-based drugs.
- Existing fluorescent sensors are insufficient for studying the biological behavior of Pt(IV) precursors.
- There is a need for biocompatible, multifunctional fluorescent sensors to track Pt(IV) loading, transport, and release.
Purpose of the Study:
- To design and develop a novel fluorescent molecule, CHTPA, for sensitive and selective detection of Pt(IV) ions.
- To investigate the mechanism of CHTPA sensing for Pt(IV).
- To utilize CHTPA-loaded polymer dots (Pdots) for visualizing and controlling the delivery and release of Pt(IV) in living cells.
Main Methods:
- Synthesis and characterization of the fluorescent molecule (E)-6-(diethylamino)-N'-(4-(diphenylamino) benzylidene)-2-oxo-2H-chromene-3 carbohydrazide (CHTPA).
- Sensing of Pt(IV) using CHTPA, with mechanism elucidated by various spectroscopic techniques (X-ray absorption near edge spectroscopy, UV-vis absorption spectroscopy, 1H NMR, Fourier transform infrared spectra).
- Preparation of nonconjugated polymer dots (Pdots) using amphiphilic block copolymer poly(ethyloxide)-block-polystyrene (PEO-b-PS) for Pt(IV) encapsulation and controlled release.
- Cellular imaging experiments in MCF-7 cells to demonstrate visualized delivery and sustained release of Pt(IV) by Pdots.
Main Results:
- CHTPA demonstrated high sensitivity and selectivity for Pt(IV) detection, with fluorescence intensity increasing proportionally to Pt(IV) concentration.
- The sensing mechanism was confirmed to be photo-induced electron transfer.
- CHTPA-Pt(IV) complexes showed Pt(IV) release in aqueous solution, accompanied by aggregation-induced emission.
- PEO-b-PS based Pdots effectively controlled Pt(IV) release, exhibited good monodispersity, and low cytotoxicity.
- Pdots successfully delivered Pt(IV) into MCF-7 cells, enabling visualized intracellular delivery and sustained release.
Conclusions:
- A novel biocompatible fluorescent sensor (CHTPA) was successfully developed for Pt(IV) detection.
- Polymer dots (Pdots) serve as effective carriers for visualized intracellular delivery and sustained release of Pt(IV).
- This study offers a new strategy for designing multifunctional fluorescent sensors for studying platinum drug delivery in cellular environments.
