Ultra-bright and stimuli-responsive fluorescent nanoparticles for bioimaging

Area of Science:

• Nanotechnology
• Bioimaging
• Materials Science

Background:

• Fluorescent nanoparticles (NPs) are advanced contrast agents for bioimaging, offering potential biocompatibility advantages over semiconductor quantum dots.
• Ultra-bright NPs are achieved through heavy doping, leading to dye proximity and potential quenching phenomena like aggregation-caused quenching (ACQ) and proximity-caused quenching (PCQ).
• Förster resonance energy transfer (FRET) can exacerbate quenching, limiting nanoprobe performance.

Purpose of the Study:

• To discuss strategies for creating ultra-bright fluorescent nanoparticles that circumvent ACQ and PCQ.
• To explore the use of aggregation-induced emission (AIE) for enhanced nanoprobe brightness.
• To present disaggregation-induced emission (DIE) as an alternative to AIE for designing stimuli-responsive fluorogenic probes.

Main Methods:

• Reviewing strategies to avoid aggregation-caused quenching (ACQ) and proximity-caused quenching (PCQ) in fluorescent nanoparticles.
• Investigating the principles of aggregation-induced emission (AIE) for enhancing fluorescence.
• Examining disaggregation-induced emission (DIE) as a method for creating stimuli-responsive probes.

Main Results:

• Identified strategies to achieve ultra-bright fluorescent nanoparticles by mitigating ACQ and PCQ.
• Highlighted the potential of AIE in developing brighter nanoprobes.
• Demonstrated the utility of DIE for creating stimuli-responsive probes from diverse precursors, contrasting with the limited precursors for AIE.

Conclusions:

• Ultra-bright fluorescent nanoparticles can be designed by avoiding detrimental dye-dye interactions.
• Both AIE and DIE offer pathways to enhance fluorescence and create novel responsive materials.
• DIE presents a versatile approach for stimuli-responsive probe development, applicable to a broader range of materials than AIE.