FRET distance dependence from upconverting nanoparticles to quantum dots

TL;DR

This study investigates how the distance between upconverting nanoparticles and quantum dots affects FRET efficiency, using experimental and theoretical methods to optimize biosensing applications.

Contribution

It introduces a combined experimental and theoretical approach to analyze UCNP-QD FRET dependence on distance, providing insights for improving biosensing performance.

Findings

FRET efficiency depends on the nanometric silica shell controlling UCNP-QD distance.

A theoretical model reproduces experimental FRET results based on erbium ion distribution.

Strategies to enhance FRET efficiency are explored through the model.

Abstract

F\"orster resonant energy transfer (FRET) with upconverting nanoparticles (UCNPs) as donors and quantum dots (QDs) as acceptors has been regarded as a promising tool for biosensing applications. In this work, we use time-resolved fluorescence spectroscopy to analyze the UCNP-to-QD FRET and we focus on the most relevant parameter of the FRET phenomenon, UCNP-QD distance. This distance is controlled by a nanometric silica shell around the UCNP surface. We theoretically reproduce the experimental results applying FRET theory to the distribution of emitting erbium ions in the UCNP. This simple model allows us to estimate the contribution of every erbium ion to the final FRET response and to explore different strategies to improve FRET efficiency.