title: Microneedle-based transdermal sensor for on-chip potentiometric determination of K(+).
abstract: The determination of electrolytes is invaluable for point of care diagnostic applications. An ion selective transdermal microneedle sensor is demonstrated for potassium by integrating a hollow microneedle with a microfluidic chip to extract fluid through a channel towards a downstream solid-state ion-selective-electrode (ISE). 3D porous carbon and 3D porous graphene electrodes, made via interference lithography, are compared as solid-state transducers for ISE's and evaluated for electrochemical performance, stability, and selectivity. The porous carbon K(+) ISE's show better performance than the porous graphene K(+) ISE's, capable of measuring potassium across normal physiological concentrations in the presence of interfering ions with greater stability. This new microfluidic/microneedle platform shows promise for medical applications.
authors.affiliation: Sandia National Laboratories, Albuquerque, New Mexico, 87185, USA; Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC, 27695-7115, USA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Miller
authors.forename: Xiaoyin
authors.initials: X
authors.lastname: Xiao
authors.forename: Igal
authors.initials: I
authors.lastname: Brener
authors.forename: D Bruce
authors.initials: DB
authors.lastname: Burckel
authors.forename: Roger
authors.initials: R
authors.lastname: Narayan
authors.forename: Ronen
authors.initials: R
authors.lastname: Polsky
mesh_terms: D015374:Biosensing Techniques; D002244:Carbon / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation*; D006108:Graphite / Q000737:chemistry; D017736:Ion-Selective Electrodes; D007477:Ions / Q000737:chemistry; D046210:Microfluidic Analytical Techniques; D016062:Porosity; D011188:Potassium / Q000032:analysis*
chemical_list: D007477:Ions; D002244:Carbon; D006108:Graphite; D011188:Potassium
keywords: electrochemistry; microneedles; point-of-care; sensors; two-photon polymerization