Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms

Vikhram Vilasur Swaminathan, Piyush Dak, Bobby Reddy, Eric Salm, Carlos Duarte-Guevara, Yu Zhong, Andrew Fischer, Yi Shao Liu, Muhammad A. Alam, Rashid Bashir

Research output: Contribution to journalArticlepeer-review


The ability to control the ionic environment in saline waters and aqueous electrolytes is useful for desalination as well as electronic biosensing. We demonstrate a method of electronic desalting at micro-scale through on-chip micro electrodes. We show that, while desalting is limited in bulk solutions with unlimited availability of salts, significant desalting of ≥1 mM solutions can be achieved in sub-nanoliter volume droplets with diameters of ∼250 μm. Within these droplets, by using platinum-black microelectrodes and electrochemical surface treatments, we can enhance the electrode surface area to achieve >99% and 41% salt removal in 1 mM and 10 mM salt concentrations, respectively. Through self-consistent simulations and experimental measurements, we demonstrate that conventional double-layer theory over-predicts the desalting capacity and, hence, cannot be used to model systems that are mass limited or undergoing significant salt removal from the bulk. Our results will provide a better understanding of capacitive desalination, as well as a method for salt manipulation in high-throughput droplet-based microfluidic sensing platforms.

Original languageEnglish (US)
Article number053105
JournalApplied Physics Letters
Issue number5
StatePublished - Feb 2 2015

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


Dive into the research topics of 'Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms'. Together they form a unique fingerprint.

Cite this