Optimization of Fluorescent Nanoparticles Architecture for Efficient Brightness, FRET Efficiency and Biosensing

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Controlling fluorophore localization in polymer nanoparticles is crucial for optimizing brightness, Förster Resonance Energy Transfer (FRET), and biosensing.
• Existing methods face challenges in achieving precise spatial control of dyes within nanoparticles.

Purpose of the Study:

• To develop a method for architecturally controlled synthesis of fluorescent polymer nanoparticles with tunable dye localization.
• To investigate the impact of dye positioning (core, shell, or both) on nanoparticle properties and biosensing performance.

Main Methods:

• Controlled radical polymerization in miniemulsion using polymerizable BODIPY monomers in a one-pot, water-based process.
• Synthesis of core-shell-crown fluorescent polymer nanoparticles with covalent dye incorporation.
• Evaluation of FRET efficiency, brightness, and analytical sensitivity in a biotin-streptavidin assay.

Main Results:

• Achieved precise spatial confinement of BODIPY dyes within nanoparticle compartments, preventing leakage.
• Demonstrated a brightness/distance trade-off: core-confined dyes maximized brightness, while shell-localized dyes enhanced FRET efficiency (up to 75%).
• Optimized nanoparticles achieved a limit of detection of ~4-8 nM in a competitive assay, showing high analytical sensitivity.

Conclusions:

• Architectural control over fluorophore localization in polymer nanoparticles enables independent optimization of brightness and FRET.
• These scalable, metal-free nanotransducers show significant potential for sensitive, point-of-care biosensing applications.
• Nanoparticle brightness is a key factor determining analytical sensitivity in competitive assays.