Comparative review of interferometric detection of plasmonic nanoparticles

Abstract

Noble metal nanoparticles exhibit enhanced scattering and absorption at specific wavelengths due to a localized surface plamson resonance. This unique property can be exploited to enable the use of plasmonic nanoparticles as contrast agents in optical imaging. A range of optical techniques have been developed to detect nanoparticles in order to implement imaging schemes. Here we review several different approaches for using optical interferometry to detect the presence and concentration of nanoparticles. The strengths and weaknesses of the various approaches are discussed and quantitative comparisons of the achievable signal to noise ratios are presented. The benefits of each approach are outlined as they relate to specific application goals.

Reflected light microspectroscopy for single-nanoparticle biosensing

“…1,2 Plasmonic NP is in many ways the smallest biophysical transducer, giving unprecedented access to biochemical events at the molecular level. A NP's resonance excitation of localized plasmonic oscillation is sensitive to the NP's environment, charge, and size and is detected in the far field by optical microspectroscopy in the form of NP scattering, [3][4][5][6][7] absorption, 8,9 or extinction. 10 Successful implementation of single-particle biosensing technology equally depends on the performance and simplicity of the NP imaging setup and adapted fluidic system.…”

Fast wide-field photothermal and quantitative phase cell imaging with optical lock-in detection

“…The spectral peak of the LSPR is dictated by the size, shape, and composition of the NP [ 1 ]. Multiple optical techniques have been established to detect NPs on multiple substrates [ 2 ]. These include, among others, dark-field microscopy [ 3 ], which takes advantage of enhanced NP scattering at their plasmonic resonance wavelength, and photothermal microscopy, which visualizes refractive index changes in the sample media due to localized NP heating [ 4 – 9 ].…”

Introduction: feature issue on optical molecular probes, imaging, and drug delivery

“…For Raman-based instrumentation, a miniaturized lens assembly is presented that maintains high quality microscopy images while decreasing the size of coherent Raman scattering imaging probes [3]. Different optical interferometric approaches to detect the presence and concentration of plasmonic nanoparticle contrast agents are described and compared quantitatively in [4]. The feasibility of using immunolabeled gold nanorods (GNRs) to classify normal and malignant brain tissues is evaluated for application to tumor margin delineation during surgical procedures [5].…”