title: Single step nanoplasmonic immunoassay for the measurement of protein biomarkers.
abstract: A nanoplasmonic biosensor for highly-sensitive, single-step detection of protein biomarkers is presented. The principle is based on the utilization of the optical scattering properties of gold nanorods (GNRs) conjugated to bio-recognition molecules. The nanoplasmonic properties of the GNRs were utilized to detect proteins using near-infrared light interferometry. We show that the antibody-conjugated GNRs can specifically bind to our model analyte, Glucose Transporter-1 (Glut-1). The signal intensity of back-scattered light from the GNRs bound after incubation, correlated well to the Glut-1 concentration as per the calibration curve. The detection range using this nanoplasmonic immunoassay ranges from 10 ng/mL to 1 ug/mL for Glut-1. The minimal detectable concentration based on the lowest discernable concentration from zero is 10 ng/mL. This nanoplasmonic immunoassay can act as a simple, selective, sensitive strategy for effective disease diagnosis. It offers advantages such as wide detection range, increased speed of analysis (due to fewer incubation/washing steps), and no label development as compared to traditional immunoassay techniques. Our future goal is to incorporate this detection strategy onto a microfluidic platform to be used as a point-of-care diagnostic tool.
authors.affiliation: Department of Ophthalmology, University of Miami-Bascom Palmer Eye Institute, Miami, FL 33136, USA; E-Mails: sprabhulkar@med.miami.edu (S.P.); asparanjape@gmail.com (A.P.).
authors.forename: Shradha
authors.initials: S
authors.lastname: Prabhulkar
authors.affiliation: Department of Structural Biology, Stanford University, Palo Alto, CA 94305, USA; E-Mail: adlz@stanford.edu.
authors.forename: Adam
authors.initials: A
authors.lastname: de la Zerda
authors.affiliation: Department of Ophthalmology, University of Miami-Bascom Palmer Eye Institute, Miami, FL 33136, USA; E-Mails: sprabhulkar@med.miami.edu (S.P.); asparanjape@gmail.com (A.P.).
authors.forename: Amit
authors.initials: A
authors.lastname: Paranjape
authors.affiliation: Department of Ophthalmology, University of Miami-Bascom Palmer Eye Institute, Miami, FL 33136, USA; E-Mails: sprabhulkar@med.miami.edu (S.P.); asparanjape@gmail.com (A.P.).
authors.forename: Richard M
authors.initials: RM
authors.lastname: Awdeh
keywords: glucose transporter-1; gold nanorods; immunoassay; optical coherence tomography; protein biomarkers; surface plasmon resonance