"Turn-on" fluorescence probe integrated polymer nanoparticles for sensing biological thiol molecules

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Intracellular thiol detection is crucial for understanding biological processes and diagnosing diseases.
• Existing methods for thiol sensing often lack specificity or sensitivity.
• Fluorescence probes offer a sensitive detection method, but require careful design for biological applications.

Purpose of the Study:

• To develop a "turn-on" fluorescence probe integrated into polymeric nanoparticles for sensitive and selective intracellular thiol detection.
• To elucidate the photo-induced electron transfer mechanism governing the probe's response to thiols.
• To evaluate the probe's performance in complex biological matrices, including live cancer cells.

Main Methods:

• Synthesis of a "turn-on" thiol-responsive fluorescence probe and its incorporation into polymeric nanoparticles.
• Utilizing photo-induced electron transfer (PET) principles for probe design.
• Employing Configuration Interaction Singles (CIS) calculations to confirm the sensing mechanism.
• Conducting selectivity studies with biological thiols and amino acids.
• Performing kinetic and electrochemical studies to determine reaction thermodynamics.
• Testing the probe in cancer cells, with and without a targeting ligand.

Main Results:

• The synthesized probe exhibits a "turn-on" fluorescence response upon reaction with thiols, indicating successful probe design.
• The probe-integrated nanoparticles demonstrated high selectivity for biological thiols over non-thiolated amino acids.
• CIS calculations confirmed the PET mechanism, explaining the probe's "turn-on" behavior.
• Kinetic and electrochemical analyses provided insights into the reaction rates and Gibbs free energy.
• In vitro studies showed effective sensing of intracellular thiols in cancer cells, with enhanced selectivity using a targeting ligand.

Conclusions:

• A novel "turn-on" fluorescence probe in polymeric nanoparticles enables sensitive and selective detection of intracellular thiols.
• The developed system offers a promising platform for real-time monitoring of thiol levels in biological systems.
• This technology holds potential as a diagnostic tool for thiol-related diseases, including cancer.