Highly Emissive BODIPY-Grafted Polymer Dots for Cellular and Tissular STED Imaging

Area of Science:

• Advanced optical microscopy techniques
• Nanomaterials for bioimaging

Background:

• Stimulated emission depletion (STED) microscopy demands fluorescent probes with high brightness, photostability, and specific optical properties.
• Existing polymer dots (Pdots) often exhibit broad spectra or insufficient STED response, limiting their application in STED imaging.
• There is a need for improved Pdots that meet the stringent requirements of STED microscopy.

Purpose of the Study:

• To develop a general method for synthesizing Pdots with optimized optical properties for STED microscopy.
• To create Pdots with narrow spectral features and enhanced STED response.
• To demonstrate the utility of these novel Pdots in high-resolution STED imaging applications.

Main Methods:

• Grafting boron-dipyrromethene (BODIPY) chromophores onto a polystyrene backbone to achieve narrow spectral profiles.
• Precisely controlling the grafting ratio to minimize aggregation-induced quenching and maximize single-particle brightness.
• Synthesizing three-color Pdots and evaluating their optical properties and performance in STED imaging.

Main Results:

• Synthesized Pdots with narrow spectral features and significantly reduced aggregation-induced quenching.
• Achieved 2-10 times higher single-particle brightness compared to Pdots with encapsulated BODIPYs.
• Demonstrated successful STED imaging of single particles, cells, and tissue sections with high spatial resolution.

Conclusions:

• The developed strategy enables the creation of Pdots with desirable optical properties for STED microscopy.
• These Pdots exhibit superior brightness and photostability, facilitating subdiffraction-limit imaging.
• The Pdots show great potential for applications in in vitro diagnostics and biomedical imaging.