Light‐Addressable Ion Sensing for Real‐Time Monitoring of Extracellular Potassium

Abstract

We report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+‐selective film to the solution phase. The resulting voltammetric response is shown to be K+‐selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.

Spectroelectrochemical Evidence of Interconnected Charge and Ion Transfer in Ultrathin Membranes Modulated by a Redox Conducting Polymer

“…Our group members have demonstrated vast experience in the use of the conducting polymer poly(3-octylthiophene) (POT) as well as self-assembled monolayers for this purpose. 9 − 13 Focusing particularly on POT, the gradual oxidation of neutral POT 0 to POT + is connected to the presence of lipophilic anions in the ISM, e.g., in the cation exchanger tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, Na + TFPB – , that stabilizes the generated positive charge. Then, to maintain the electroneutrality condition, the “hydrophilic” counter-cation (e.g., Na + ) is expelled from the membrane to the solution.…”

Surface Patterning of Biomolecules Using Click Chemistry and Light‐Activated Electrochemistry to Locally Generate Cu(I)

“…Light activated electrochemistry (LAE) is a technique capable of spatially resolving faradaic electrochemistry with a focused light beam illuminated on an unpatterned semiconductor electrode surface [10] . The addressability of light to confine electrochemistry at multiple regions of the electrode without perturbing the electrolyte solution (i.e hydrodynamic forces) makes LAE ideal for electrodepositing multiple metals, [11] oxides [12] and polymers, [10] selectively releasing captured single circulating tumour cells, [13] and locally monitoring extracellular potassium on drug stimulated cells [14] . However, the technique has not been utilized for the localized bioconjugation yet.…”

Potentiometric detection of glucose based on oligomerization with a diboronic acid using polycation as an indicator

“…Highly affinitive receptors such as antibodies, aptamers, molecularly imprinted polymers, and ionophores have been screened or synthesized as recognition elements in construction of sensors with various kinds of readout strategies. [2][3][4][5][6][7][8][9][10][11][12] It is very challenging to achieve selective detection when specic receptors are unavailable, especially for those target molecules which have structurally similar stereoisomers. 13 Therefore, developing affinity-independent methods for selective target sensing is highly desired.…”