Single-Impact Electrochemistry in Paper-Based Microfluidics

Lennart J.K. Weiß, Georg Lubins, Emir Music, Philipp Rinklin, Marko Banzet, Hu Peng, Korkut Terkan, Dirk Mayer, Bernhard Wolfrum

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Microfluidic paper-based analytical devices (μPADs) have experienced an unprecedented story of success. In particular, as of today, most people have likely come into contact with one of their two most famous examples-the pregnancy or the SARS-CoV-2 antigen test. However, their sensing performance is constrained by the optical readout of nanoparticle agglomeration, which typically allows only qualitative measurements. In contrast, single-impact electrochemistry offers the possibility to quantify species concentrations beyond the pM range by resolving collisions of individual species on a microelectrode. Within this work, we investigate the integration of stochastic sensing into a μPAD design by combining a wax-patterned microchannel with a microelectrode array to detect silver nanoparticles (AgNPs) by their oxidative dissolution. In doing so, we demonstrate the possibility to resolve individual nanoparticle collisions in a reference-on-chip configuration. To simulate a lateral flow architecture, we flush previously dried AgNPs along a microchannel toward the electrode array, where we are able to record nanoparticle impacts. Consequently, single-impact electrochemistry poses a promising candidate to extend the limits of lateral flow-based sensors beyond current applications toward a fast and reliable detection of very dilute species on site.

Original languageEnglish
Pages (from-to)884-892
Number of pages9
JournalACS Sensors
Issue number3
StatePublished - 25 Mar 2022


  • lateral flow sensor
  • paper-based microfluidics
  • silver nanoparticles
  • single-impact electrochemistry
  • μPAD


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