Inter-Nanoparticle FRET for Biosensing: Photophysics Versus Size

Area of Science:

• Nanotechnology
• Biophysics
• Materials Science

Background:

• Förster resonance energy transfer (FRET) is crucial for quantifying nanoscale distances and biomolecular interactions.
• Luminescent nanoparticles (NPs) are increasingly used in FRET, often paired with fluorescent dyes or proteins.
• Inter-NP FRET, utilizing luminescent NPs as both donor and acceptor, faces challenges due to size constraints affecting efficiency.

Purpose of the Study:

• To critically review advances and the current state-of-the-art in inter-NP FRET.
• To focus on commonly used NPs: quantum dots (QDs), upconversion nanoparticles (UCNPs), and fluorescent organic nanoparticles (FONs).
• To discuss strategies for overcoming size limitations and leveraging NP photophysical properties for enhanced FRET.

Main Methods:

• Review of existing literature on inter-NP FRET.
• Analysis of NP characteristics (size, shells, coatings) influencing FRET efficiency.
• Examination of photophysical properties of QDs, UCNPs, and FONs in FRET systems.
• Discussion of representative inter-NP FRET applications in biosensing.

Main Results:

• NP size, surface shells, and coatings can be engineered to extend FRET distances.
• Unique photophysical properties of NPs offer solutions to overcome inherent limitations.
• High FRET efficiencies (up to 90%) are achievable, demonstrating potential for bioanalytical applications.
• Luminescent NPs offer high brightness, photostability, NIR excitation/emission, multiplexing, and bioconjugation capabilities.

Conclusions:

• Inter-NP FRET with luminescent NPs shows significant promise for advanced biosensing.
• Engineering NP properties is key to maximizing FRET efficiency and expanding applications.
• The unique advantages of luminescent NPs facilitate their translation into practical bioanalytical tools.