Förster Energy Transfer in Core–Shell Nanoparticles: Theoretical Model and Monte Carlo Study

Anna Synak,Piotr Bojarski,Agnieszka Schlichtholz,Leszek Kułak

doi:10.1021/acs.jpcc.1c05314

Anna Synak, Piotr Bojarski + Show 2 more

Open Access

https://doi.org/10.1021/acs.jpcc.1c05314

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Abstract

The model of Förster excitation energy transfer on a spherical core–shell nanoparticle was presented. A general expression for fluorescence intensity decay was obtained for an arbitrary number of acceptors linked chemically to the shell. It was found that the dynamical behavior of the system is extremely sensitive to the number of acceptors and the size of the nanoparticle. Monte Carlo simulations performed for the energy transfer parameters taken from an independent experiment show excellent agreement with the model for donor fluorescence decay and its mean lifetime. The original model was then extended to the common experimental case of core–shell nanoparticle size distribution, assuming the Gaussian distribution function of their radii. This effect leads to slower fluorescence decays and longer mean fluorescence lifetimes, as revealed by Monte Carlo simulations.

Highlights

Electronic excitation energy transfer by the dipole−dipole or Förster mechanism[1] is an important physical process occurring in the nanoscale that is employed as an effective tool to study the properties of nanomaterials and special systems such as interfaces, fractal structures, colloids, aggregated systems, plasmonic platforms, or some ordered systems.[2−17] It is widely used to study end-to-end distance and conformations of many macromolecules and proximity, interactions, and actions of biologically important species such as albumins, DNA, or enzymes, to name just a few.[18−28]
Core−shell nanoparticles belong nowadays to the most intensively studied multifunctional nanomaterials. This is due to their unique properties resulting from especially designed core and shell components of different physicochemical properties.[29−32] Core−shell nanoparticles have been applied in different areas of science and nanotechnology such as biosensing, photocatalysis, drug delivery systems, targeted therapies, and plasmonically enhanced fluorescence.[33−39] Core−shell nanostructures are composed of at least two different phases of complementary properties, that is, the core surrounded by an external layer called the shell
The values of the radius of core−shell nanoparticles R = 25 nm and R = 50 nm, typical of many experiments, were assumed in the Monte Carlo simulation to compare the effect of size on fluorescence intensity decay in the presence of energy transfer

Summary

INTRODUCTION

Electronic excitation energy transfer by the dipole−dipole or Förster mechanism[1] is an important physical process occurring in the nanoscale that is employed as an effective tool to study the properties of nanomaterials and special systems such as interfaces, fractal structures, colloids, aggregated systems, plasmonic platforms, or some ordered systems.[2−17] It is widely used to study end-to-end distance and conformations of many macromolecules and proximity, interactions, and actions of biologically important species such as albumins, DNA, or enzymes, to name just a few.[18−28]. The probability per time unit of Förster resonance energy transfer (FRET) depends on the intermolecular distance, relative orientation, and motion of donor and acceptor transition moments In this way, the kinetics of molecular fluorescence in the presence of FRET can reflect both structural and dynamical aspects of the studied nanostructures. Core−shell nanoparticles belong nowadays to the most intensively studied multifunctional nanomaterials This is due to their unique properties resulting from especially designed core and shell components of different physicochemical properties.[29−32] Core−shell nanoparticles have been applied in different areas of science and nanotechnology such as biosensing, photocatalysis, drug delivery systems, targeted therapies, and plasmonically enhanced fluorescence.[33−39] Core−shell nanostructures are composed of at least two different phases of complementary properties, that is, the core surrounded by an external layer called the shell. Quantitative discussion making use of Monte Carlo simulations in selected more complex cases will be given

THEORY

RESULTS AND DISCUSSION

CONCLUSIONS

■ REFERENCES