TY - JOUR
T1 - Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms
AU - Swaminathan, Vikhram Vilasur
AU - Dak, Piyush
AU - Reddy, Bobby
AU - Salm, Eric
AU - Duarte-Guevara, Carlos
AU - Zhong, Yu
AU - Fischer, Andrew
AU - Liu, Yi Shao
AU - Alam, Muhammad A.
AU - Bashir, Rashid
N1 - Publisher Copyright:
© 2015 AIP Publishing LLC.
PY - 2015/2/2
Y1 - 2015/2/2
N2 - 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.
AB - 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.
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U2 - 10.1063/1.4907351
DO - 10.1063/1.4907351
M3 - Article
C2 - 25713471
AN - SCOPUS:84923862777
SN - 0003-6951
VL - 106
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 5
M1 - 053105
ER -