Single chip SPR and fluorescent ELISA assay of prostate specific antigen

Abstract

A multi-channel system combining fluidics and micropatterned plasmonic materials with wavelength interrogation surface plasmon resonance (SPR) and fluorescence detection was integrated from the combination of a small and motorized fluorescence microscope mounted on a portable 4-channel SPR instrument. The SPR and fluorescent measurements were performed based on the same detection area in a multi-channel fluidic, with a sensing scheme for prostate-specific antigen (PSA) consisting of a sandwich assay with a capture anti-PSA immobilized onto the SPR sensor and a detection anti-PSA modified with horseradish peroxidase (HRP). In this dual-detection instrument, fluorescence was measured from the solution side of the micropatterned gold film, while the interface between the glass prism and the gold film served to interrogate the SPR response. The SPR sensors were comprised of microhole arrays fabricated by photolithography to enhance the instrumental response for PSA detection by approximately a factor of 2 to 3 and they were coated with a self-assembled monolayer of a peptide (3-MPA-HHHDD-OH) to minimize nonspecific adsorption. PSA was successfully detected at clinical concentrations from 10 pM to 50 nM with this integrated system in a single assay lasting 12 minutes, almost centering on the desired range for PSA diagnostic tests (>4 ng mL(-1) or >150 pM). The combination of two robust techniques in a single chip and instrument has led to a simple and effective assay that can be carried out on a small and portable instrument providing rapid biodetection of an important cancer biomarker with a dynamic range of nearly 4 orders of magnitude in the clinical range.

Dielectrophoresis‐Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO2 Nanorod Arrays

“…While their platform provides an overall detection strategy on bead‐based technology, our device offers a general enrichment method for sample preconcentration. Breault‐Turcot et al, employing a combination of surface plasmon resonance and fluorescence to detect PSA, attained a detection limit of 10 pM (0.3 ng mL −1 ) . Sanghavi et al using nanoslit and nDEP to enrich PSA biomarker demonstrated a sensitivity level of 5 pg mL −1 , while the fabrication of their device involved complex electron beam lithography .…”

“…Breault-Turcot et al, employing a combination of surface plasmon resonance and fluorescence to detect PSA, attained a detection limit of 10 pM (0.3 ng mL −1 ). [38] Sanghavi et al using nanoslit and nDEP to enrich PSA biomarker demonstrated a sensitivity level of 5 pg mL −1 , while the fabrication of their device involved complex electron beam lithography. [22] Therefore, the device reported here exhibits comparable or higher sensitivity in detecting real samples for clinical use.…”

Refractive Index and Sensing of Glucose Molarities determined using Au-Cr K-SPR at 670/785 nm Wavelength

“…In previous work, the detection of prostate specific antigen (PSA) was achieved using a multi-channel Lab-on-a-chip (LoC) system which combined micropatterned plasmonic materials with K-SPR, fluorescence detection and microfluidics. The dual SPRfluorescence assay detected PSA at concentrations of 10 pM to 50 nM with an analysis time of 12 min which was relevant for clinical diagnostics (Breault-Turcot et al 2015). Various miniaturized K-SPR biosensors utilizing microfluidics for PoC applications with low detection limits and quick analysis have also been researched previously (Wang & Fan 2016).…”

Vertically sheathing laminar flow-based immunoassay using simultaneous diffusion-driven immune reactions

“…14 Various microuidics-based immunoassay methods have been developed to address the limitations of conventional assay platforms. They exploited a variety of different approaches, such as the automated lab-on-a-disc devices, 15,16 integration of an optical system in the microuidic devices, [17][18][19] a quantum dot (QD) "barcoding" system, 20,21 and the three-dimensional microuidic connement. 22,23 Despite considerable efforts in the microuidic immunoassay platforms in the past decades, most researches have focused on automation, [24][25][26] increased surface areas, 27,28 improved reporter probes, 29,30 and distinctive detection principles; 31,32 however, the efficient delivery of antibody reagents to the reaction sites has been rarely explored.…”