Jump to main content
Jump to site search

Issue 2, 2017
Previous Article Next Article

A new microfluidic approach for the one-step capture, amplification and label-free quantification of bacteria from raw samples

Author affiliations

Abstract

A microfluidic method to specifically capture and detect infectious bacteria based on immunorecognition and proliferative power is presented. It involves a microscale fluidized bed in which magnetic and drag forces are balanced to retain antibody-functionalized superparamagnetic beads in a chamber during sample perfusion. Captured cells are then cultivated in situ by infusing nutritionally-rich medium. The system was validated by the direct one-step detection of Salmonella Typhimurium in undiluted unskimmed milk, without pre-treatment. The growth of bacteria induces an expansion of the fluidized bed, mainly due to the volume occupied by the newly formed bacteria. This expansion can be observed with the naked eye, providing simple low-cost detection of only a few bacteria and in a few hours. The time to expansion can also be measured with a low-cost camera, allowing quantitative detection down to 4 cfu (colony forming unit), with a dynamic range of 100 to 107 cfu ml−1 in 2 to 8 hours, depending on the initial concentration. This mode of operation is an equivalent of quantitative PCR, with which it shares a high dynamic range and outstanding sensitivity and specificity, operating at the live cell rather than DNA level. Specificity was demonstrated by controls performed in the presence of a 500× excess of non-pathogenic Lactococcus lactis. The system's versatility was demonstrated by its successful application to the detection and quantitation of Escherichia coli O157:H15 and Enterobacter cloacae. This new technology allows fast, low-cost, portable and automated bacteria detection for various applications in food, environment, security and clinics.

Graphical abstract: A new microfluidic approach for the one-step capture, amplification and label-free quantification of bacteria from raw samples

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 30 Aug 2016, accepted on 09 Oct 2016 and first published on 10 Oct 2016


Article type: Edge Article
DOI: 10.1039/C6SC03880H
Citation: Chem. Sci., 2017,8, 1329-1336
  • Open access: Creative Commons BY-NC license
  •   Request permissions

    A new microfluidic approach for the one-step capture, amplification and label-free quantification of bacteria from raw samples

    I. Pereiro, A. Bendali, S. Tabnaoui, L. Alexandre, J. Srbova, Z. Bilkova, S. Deegan, L. Joshi, J. Viovy, L. Malaquin, B. Dupuy and S. Descroix, Chem. Sci., 2017, 8, 1329
    DOI: 10.1039/C6SC03880H

Search articles by author