Increasing the Sensitivity of Enzyme-Linked Immunosorbent Assay Using Multiplexed Electrokinetic Concentrator

Abstract

We developed a novel method to increase the sensitivity of standard Enzyme-Linked Immunosorbent Assay (ELISA) using a multiplexed electrokinetic concentration chip. The poly(dimethylsiloxane) (PDMS) molecular concentrator 1 was used to trap and collect charged fluorescent product of targetbound enzyme turnover reaction of ELISA that occurred in a standard 96 well plate. Detection sensitivities of both Prostate Specific Antigen (PSA) and CA 19-9 (a human pancreatic and gastrointestinal cancer marker) ELISAs in serum are enhanced ~100 fold with a low CV of <17%. We also integrated this method with an on-chip bead-based ELISA that lends itself toward a fullyautomated on-chip diagnostic device. Detection sensitivity of microfluidic bead-based CA 19-9 ELISA in serum is enhanced ~65 fold compared to the results without electrokinetic accumulation step. This chip can be directly applied to enhance the readout sensitivity of a wide range of existing ELISA kits at concentrations below the current detection limit.

Microfluidic Chips for Point‐of‐Care Immunodiagnostics

“…Electrokinetic accumulation can be used to increase the sensitivity of enzyme-linked immunosorbent assay (ELISA) 65-fold. [ 131 ] Proteins can be preconcentrated using absorbent particles in alternating microfl uidic fl ows of lipid and aqueous phase. [ 132 ] An alternative is to preconcentrate proteins using fi ltration.…”

Zinc oxide nanoparticle-enhanced ultrasensitive chemiluminescence immunoassay for the carcinoma embryonic antigen

“…Sensitive detection of the biomarkers is vitally important for timely diagnosis and treatment of early stage cancers, which largely determines the survival rate of cancer patients [1,2]. Immunoassay is an easy and low-cost method in the detection of antigen or its specific antibody in clinical diagnostics [3].…”

Magnetic Fe3O4‐Au core‐shell nanostructures for surface enhanced Raman scattering

“…Of these nanostructures, gold nanoparticles have been the focus of intense research, mainly due to their fascinating optical properties, particularly surface plasmon resonance (SPR) absorption [1][2][3][4][5][6][7] and surface enhanced Raman scattering (SERS) [8][9][10][11][12][13][14]. Due to its advantage of molecular specificity [15][16][17], SERS is highly adequate for the detection of a wide variety of analytes, including biomolecules [18][19][20][21], chemical agents [22][23][24], and explosives [25][26][27].…”