Jump to main content
Jump to site search

Issue 23, 2009

Toward one-step point-of-care immunodiagnostics using capillary-driven microfluidics and PDMS substrates

Author affiliations

Abstract

Point-of-care diagnostics will strongly benefit from miniaturization based on microfluidics because microfluidics integrate functions that can together preserve valuable samples and reagents, increase sensitivity of a test, and accelerate mass transport limited reactions. But a main challenge is to incorporate reagents into microfluidics and to make microfluidics simple to use. Here, we integrate microfluidic functional elements, some of which were developed earlier, and reagents such as detection antibodies (dAbs), capture antibodies (cAbs) and analyte molecules for making one-step immunoassays: the integrated device only requires the addition of sample to trigger a cascade of events powered by capillary forces for effecting a sandwich immunoassay that is read using a fluorescence microscope. The microfluidic elements comprise a sample collector, delay valves, flow resistors, a deposition zone for dAbs, a reaction chamber sealed with a polydimethylsiloxane (PDMS) substrate, and a capillary pump and vents. Parameters for depositing 3.6 nL of a solution of dAb on the chip using an inkjet are optimized and the PDMS substrate is patterned with analytes, which provide a positive control, and cAbs. Various storage conditions of the patterned PDMS are investigated for up to 6 months revealing that storage with a desiccant preserved at least 51% of the activity of the cAbs. C-reactive protein (CRP), a general inflammation and cardiac marker, is detected using this one-step chip using only 5 µL of human serum by measuring fluorescent signals from 30 × 100 µm2 areas of the PDMS substrate in the wet reaction chamber. The one-step chip can detect CRP at a concentration of 10 ng mL−1 in less than 3 min and below 1 ng mL−1 within 14 min. The work presented here may spur the adoption of fluorescence immunoassays using capillary driven microfluidics and PDMS substrates for point-of-care diagnostics.

Graphical abstract: Toward one-step point-of-care immunodiagnostics using capillary-driven microfluidics and PDMS substrates

Supplementary files

Article information


Submitted
03 Apr 2009
Accepted
28 Jul 2009
First published
21 Aug 2009

Lab Chip, 2009,9, 3330-3337
Article type
Paper

Toward one-step point-of-care immunodiagnostics using capillary-driven microfluidics and PDMS substrates

L. Gervais and E. Delamarche, Lab Chip, 2009, 9, 3330 DOI: 10.1039/B906523G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements