Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms
Date of this Version
2-2-2015Abstract
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.
Discipline(s)
Biomedical | Diagnosis | Electronic Devices and Semiconductor Manufacturing
Download
Comments
This is the publisher PDF of Swaminathan, VV, Dak, P, Reddy Jr., B, Salm, E., Duarte-Guevara, C., Zhong, Y., Fischer, A., Liu, Y-S, Alam, MA, Bashir, R. "Electronic desalting for controlling the ionic environment in droplet-based biosensing platfoms." Applied Physics Letters: 106, 053105. 2015. Copyright AIP, available at http://scitation.aip.org/content/aip/journal/apl/106/5/10.1063/1.4907351
Supplementary Information: ftp://ftp.aip.org/epaps/appl_phys_lett/E-APPLAB-106-093505/