Nanoscale Luminescence Imaging/Detection of Single Particles: State-of-the-Art and Future Prospects

Abstract

Single-particle-level measurements, during the reaction, avoid averaging effects that are inherent limitations of conventional ensemble strategies. It allows revealing structure− activity relationships beyond averaged properties by considering crucial particle-selective descriptors including structure/morphology dynamics, intrinsic heterogeneity, and dynamic fluctuations in reactivity (kinetics, mechanisms). In recent years, numerous luminescence (optical) techniques such as chemiluminescence (CL), electrochemiluminescence (ECL), and fluorescence (FL) microscopies have been emerging as dominant tools to achieve such measurements, owing to their diversified spectroscopy principles, noninvasive nature, higher sensitivity, and sufficient spatiotemporal resolution. Correspondingly, state-of-the-art methodologies and tools are being used for probing (real-time, operando, in situ) diverse applications of single particles in sensing, medicine, and catalysis. Herein, we provide a concise and comprehensive perspective on luminescence-based detection and imaging of single particles by putting special emphasis on their basic principles, mechanistic pathways, advances, challenges, and key applications. This Perspective focuses on the development of emission intensities and imaging based individual particle detection. Moreover, several key examples in the areas of sensing, motion, catalysis, energy, materials, and emerging trends in related areas are documented. We finally conclude with the opportunities and remaining challenges to stimulate further developments in this field.

Single-particle Förster resonance energy transfer from upconversion nanoparticles to organic dyes

“…Single-particle detection and sensing is at the forefront of single-molecule imaging, enabling us to observe and analyze individual particles down to the nanometer scale. 1–7 This capability has been transformative in dissecting complex biological systems and detecting trace amounts of substances with exceptional specificity and sensitivity. The fundamental principle of this technique hinges on tracking distinct optical properties such as fluorescence 8,9 and plasmon resonance 10–12 of individual nanoparticles or molecules.…”