21 September 2015 Reflected light microspectroscopy for single-nanoparticle biosensing
Author Affiliations +
J. of Biomedical Optics, 20(9), 097001 (2015). doi:10.1117/1.JBO.20.9.097001
Conventional and dark-field microscopy in the transmission mode is extensively used for single plasmonic nanoparticle (NP) imaging and spectral analysis. However, application of the transmission mode for real-time biosensing to single NP poses strict limitations on the size and material properties of the microfluidic system. This article proposes a simple optical technique based on reflected light microscopy to perform microspectroscopy of a single NP placed in a conventional, nontransparent liquid delivery system. The insertion of a variable spot diaphragm in the optical path reduces the interference effect that occurs at the NP-substrate interface and improves the signal-to-noise ratio in NP imaging. Using this method, we demonstrated spatial imaging and spectral analyses of 60-, 80-, and 100-nm single gold NPs. A single-NP sensor based on a 100-nm NP was used for real-time measurement of bulk refractive index changes in the microfluidic channel and for detection of fast dynamic poly(ethylene glycol) attachment to the NP surface. Finally, electrochemical single-particle microspectroscopy was demonstrated by using a methylene blue electroactive redox tag. The proposed optical approach is expected to significantly improve the miniaturization and multiplexing capabilities of high-throughput biosensing based on single NP.
© 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)
Sergiy Patskovsky, Michel Meunier, "Reflected light microspectroscopy for single-nanoparticle biosensing," Journal of Biomedical Optics 20(9), 097001 (21 September 2015). https://doi.org/10.1117/1.JBO.20.9.097001

Back to Top