Functionalized electrospun poly(vinyl alcohol) nanofibers for on-chip concentration of E. coli cells
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Positively and negatively charged electrospun poly(vinyl alcohol) (PVA) nanofibers were incorporated into poly(methyl methacrylate) (PMMA) microchannels in order to facilitate on-chip concentration of Escherichia coli K12 cells. The effects of fiber distribution and fiber mat height on analyte retention were investigated. The 3D morphology of the mats was optimized to prevent size-related retention of the E. coli cells while also providing a large enough surface area for analyte concentration. Positively charged nanofibers produced an 87 % retention and over 80-fold concentration of the bacterial cells by mere electrostatic interaction, while negatively charged nanofibers reduced nonspecific analyte retention when compared to an empty microfluidic channel. In order to take advantage of this reduction in nonspecific retention, these negatively charged nanofibers were then modified with anti-E. coli antibodies. These proof-of-principle experiments showed that antibody-functionalized negatively charged nanofiber mats were capable of the specific capture of 72 % of the E. coli cells while also significantly reducing nonspecific analyte retention within the channel as expected. The ease of fabrication and immense surface area of the functionalized electrospun nanofibers make them a promising alternative for on-chip concentration of analytes. The pore size and fiber mat morphology, as well as surface functionality of the fibers, can be tailored to allow for specific capture and concentration of a wide range of analytes.
KeywordsElectrospun nanofibers Sample preparation Microfluidics Lab-on-a-chip
The authors are grateful for the partial support provided by the National Science Foundation (NSF) under grant no. CBET-0852900. Also, this work was performed in part at the Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation (Grant ECCS-0335765). Finally, the authors also acknowledge partial funding through the Multistate Federal Formula Grant “Development of a novel rapid-on-site biosensor for food safety” Project #2012-13-132.
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Conflict of interest
The authors declare that they have no competing interests.
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