[Analytical Chemistry] Protein Trapping in Plasmonic Nanoslit and Nanoledge Cavities: The Behavior a
A novel plasmonic nanoledge device was presented to explore the geometry-induced trapping of nanoscale biomolecules and examine a generation of surface plasmon resonance (SPR) for plasmonic sensing. To design an optimal plasmonic device, a semi-analytical model was implemented for a quantitative analysis of SPR under plane-wave illumination and a finite-difference time-domain (FDTD) simulation was used to study the optical transmission and refractive index (RI) sensitivity. In addition, total internal reflection fluorescence (TIRF) imaging was used to visualize the migration of fluorescently labeled bovine serum albumin (BSA) into the nanoslits; and fluorescence correlation spectroscopy (FCS) was further used to investigate the diffusion of BSA in the nanoslits. Transmission SPR measurements of free prostate specific antigen (f-PSA), which is similar in size to BSA, were performed to validate the trapping of the molecules via specific binding reactions in the nanoledge cavities. The present study may facilitate further development of single nanomolecule detection and new nano-microfluidic arrays for effective detection of multiple biomarkers in clinical biofluids.
Zheng Zeng, Xiaojun Shi, Taylor Mabe, Shaun Christie, Grant Gilmore, Adam W Smith, and Jianjun Wei Anal. Chem., Just Accepted Manuscript DOI: 10.1021/acs.analchem.6b04493 Publication Date (Web): April 18, 2017 Copyright © 2017 American Chemical Society