Recent Advances in Plasmonic Nanostructures Applied for Label‐free Single‐cell Analysis

Abstract

Cellular heterogeneity presents a major challenge in understanding the relationship between cells of particular genotype and response in disease. In order to characterize the cell‐to‐cell differences during the biochemical processes, single‐cell analysis is necessary. Profiting from the unique localized surface plasmon resonance (LSPR) and Mie scattering, plasmonic nanostructures have revealed stable and adjustable scattering signals, avoiding photobleaching, blinking and autofluorescence phenomenon. These characterizations are propitious to the dynamic trace and biological image of single living cells. In this review, we discuss the recent advances in plasmonic nanostructures applied for label‐free detection and monitoring of target cells at single‐cell level by using three different techniques, surface‐enhanced Raman scattering (SERS), surface‐enhanced Infrared absorption spectroscopy (SEIRAS), and dark‐field microscopy. Various avenues to design plasmonic probes combining spectra and imaging for single‐cell analysis are demonstrated as well. We hope this review can highlight the superiority of plasmonic nanostructures in single cellular analysis, and further motivate the development of label‐free cell analysis technique to elucidate cellular diversity and heterogeneity.

Optical Methods for Label-Free Detection of Bacteria

“…Dark-field microscopy is an interesting optical technique that has been successfully used to image bacteria [ 40 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ] and protozoa [ 102 , 115 ] due to its very low background, simple construction, portability, and low cost. Since plasma nanoparticles exhibit strong scattering to visible light, dark-field microscopy is a powerful tool for imaging and localization of noble metal nanoparticles in single cell analysis [ 101 , 109 , 116 , 117 ].…”