Electrospun nanofibers for microfluidic analytical systems

Nanofibers embedded with the functional polymers exhibited a charged surface. These fibers were incorporated into microfluidic channels to provide high surface area and functional surfaces within a microfluidic system. The positively or negatively charged nanofibers were fabricated by blending of hydrophilic PVA with functional polymers with available amine groups or carboxyl groups, respectively. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to confirm the presence and location of blend components in the spun fibers. Thermally stimulated current (TSC) measurements confirmed that surface-charged nanofibers showed positive or negative currents according to the functional polymers embedded with the PVA polymer. The surface-charged nanofibers were incorporated into microfluidic channels. Poly(vinyl alcohol) (PVA) blend nanofibers formulated to create variations in fiber surface chemistry were electrospun to form patterns around gold microelectrodes on a poly(methyl methacrylate) (PMMA) chip surface. These nanofiber patterns were integrated into polymer-based microfluidic channels to create a functionalized microfluidic system with potential applications in bioanalysis. Spinning conditions and microelectrodes were optimized to enable an alignment of the nanofibers across the microfluidic channel. Importantly, nanofibers within the assembled microfluidic channels were robust and did not break or wash out of the channel under extreme fluid flow conditions at linear velocities up to 13.6 mm/s.