Development of an Electrochemical Dual H2S/Ca2+Microsensor and Its in Vivo Application to a Rat Seizure Model

Jaeyoung Lee, Yoonyi Jeong, Subin Park, Minah Suh, Youngmi Lee

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4 Scopus citations


A dual electrochemical microsensor was fabricated for concurrent monitoring of hydrogen sulfide (H2S) and calcium ions (Ca2+), which are closely linked important signaling species involved in various physiological processes. The dual sensor was prepared using a dual recessed electrode consisting of two platinum (Pt) microdisks (50 μm in diameter). Each electrode was individually optimized for the best sensing ability toward a target analyte. One electrode (WE1, amperometric H2S sensor) was modified with electrodeposition of Au and electropolymerized polyaniline coating. The other electrode (WE2, all-solid-state Ca2+-selective electrode) was composed of Ag/AgCl onto the recessed Pt disk formed via electrodeposition/chloridation, followed by silanization and Ca2+-selective membrane loading. The current of WE1 and the potential of WE2 in a dual sensor responded linearly to H2S concentration and logarithm of Ca2+ concentration, respectively, without a crosstalk between the sensing signals. Both WE1 and WE2 presented excellent sensitivity, selectivity (log KH2S,iAmp≤-3.5, i = CO, NO, O2, NO2-, AP, AA, DA, and GABA; and log KCa2+,jPot≤-3.2, j = Na+, K+, and Mg2+), and fast response time with reasonable stability (during ca. 6 h in vivo experiment). Particularly, WE2 prepared using a mixture of two ionophores (ETH1001 and ETH129) and two plasticizers (2-nitrophenyl octyl ether and bis(2-ethylhexyl) sebacate) showed a very shortened response time (tR to attain the δE/δt slope of 0.6 mV/min = 3.0 ± 0.2 s, n ≥ 10), a critically required factor for real-time analysis. The developed sensor was utilized for simultaneous real-time monitoring of H2S and Ca2+ changes at the brain cortex surface of a living rat during spontaneous epileptic seizures induced by a cortical 4-aminopyridine injection. The dynamic changes of H2S and Ca2+ were clearly observed in an intimate correlation with the electrophysiological recording of seizures, demonstrating the sensor feasibility of in vivo and real-time simultaneous measurements of H2S and Ca2+.

Original languageEnglish
Pages (from-to)4089-4097
Number of pages9
JournalACS Sensors
Issue number11
StatePublished - 26 Nov 2021

Bibliographical note

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  • Ca
  • HS
  • dual electrochemical microsensor
  • in vivo simultaneous measurement
  • seizure


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