Development of a capillary flow microfluidic Escherichia coli biosensor with on-chip reagent delivery using water-solubl

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TECHNICAL PAPER

Development of a capillary flow microfluidic Escherichia coli biosensor with on-chip reagent delivery using water-soluble nanofibers Shengquan Jin • Minhui Dai Bang-ce Ye • Sam R. Nugen



Received: 12 October 2012 / Accepted: 19 January 2013 Ó Springer-Verlag Berlin Heidelberg 2013

Abstract Although the potential role of microfluidics in point of care diagnostics is widely acknowledged, the practical limitations to their use still limit deployment. Here, we developed a capillary flow microfluidic with onchip reagent delivery which combines a lateral flow assay with microfluidic technology. The horseradish peroxidase tagged antibody was electrospun in a water-soluble polyvinylpyrrolidone nanofibers and stored in a microfluidic poly(methyl methacrylate) chip. During the assay, the sample containing Escherichia coli on immunomagnetic beads came in contact with the nanofibers causing them to dissolve and release the reagents for binding. Following hybridization, the solution moved by capillary flow toward a detection zone where the analyte was quantified using chemiluminescence. The limit of detection was found to be approximately 106 CFU/mL of E. coli O157. More importantly, the ability to store sensitive reagents within a microfluidic as nanofibers was demonstrated. The fibers showed almost instant hydration and dissemination within the sample solution.

Electronic supplementary material The online version of this article (doi:10.1007/s00542-013-1742-y) contains supplementary material, which is available to authorized users. S. Jin  M. Dai  S. R. Nugen (&) Department of Food Science, University of Massachusetts Amherst, Amherst, MA, USA e-mail: [email protected] URL: http://www.umass.edu/biosensors/ S. Jin  B. Ye Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China

1 Introduction Since their introduction, microfluidics have become very popular in chemical and biological assays (Hong et al. 2010), clinical diagnosis (Du et al. 2007; Krogmeier et al. 2007; Liu et al. 2009), and environmental monitoring (Jung et al. 2011; Lefevre et al. 2012). Recently, more attention has been given to their application in point of care diagnostics in resource limited settings (Gervais and Delamarche 2009; Konry et al. 2012). These settings require a diagnostic device to be low-cost, portable, and user friendly. The cost is often reduced using polymer substrates such as polymethyl methacrylate (PMMA) (Jin et al. 2012; Nugen et al. 2009; Qi et al. 2002). Fluid transport in a microfluidic device is often controlled using external pumps such as syringe pumps, peristaltic pumps or pneumatic pumps. These pumps typically require significant peripheral equipment and therefore reduce the portability of the biosensor. Electroosmotic flow has also been successfully used in microfluidics but requires a high voltage source again, reducing portability. The incorporation of micro pumps into microfluidics