P-069

Narvydas Dėnas

narvydas.denas@ftmc.lt

Kipras Eigminas, Aušra Valiūnienė

Center for Physical Sciences and Technology (FTMC), Lithuania

Study of the electrochemical properties of membranes for the creation of biosensors

Tethered Bilayer Lipid Membranes (tBLMs) are artificial solid supported membranes comprised of an anchor in the inner leaflet and a phospholipid monolayer in the outer leaflet of the membrane. The inner leaflet is attached to the solid support via anchor group that can be adapted to bind to the used substrate [1].

To obtain high-quality fluid membranes, there must be a layer under the membrane containing water. In previous studies, anchors, which do not guarantee that the submembrane layer has enough water, were used [2]. To solve this problem, a compound well tested forming tBLMs on gold can be used. This anchor has a chain that is branched into two parts, where from the anchor attachment to the surface up to branching, there are many hydrophilic oxygen atoms. These oxygen atoms should improve the quality of the sub-membrane layer.

Electrochemical impedance spectroscopy (EIS) is often used to investigate tBLMs. Usually by changing the used potential, the EIS response also changes [3]. This causes technical difficulties for biosensors development, because by changing the potential, a different tBLMs response to the toxin is obtained, and the sensitivity of the biosensor changes. However, EIS response on oxide surfaces (e.g. fluorine-doped tin oxide(FTO)) between different potentials has been poorly studied. It is important to determine how the potential influences the tBLMs response on FTO surface and to look for characteristics that are less dependent on applied potential. This could open simpler and more accessible research on tBLMs and simplify their use for biosensing applications.

In this work, tBLMs were formed on FTO surface using different compositions of well-studied branched anchor, modified to react with oxide surface, and small, short chain spacer group. These tBLMs were studied using EIS at different potentials, from 0V to 1V vs Ag|AgCl, KClsat, and it was observed how electrochemical properties, both before and after exposure to the toxin, depend on electrode polarization. 

References

[1]  Andersson J., Front. Mater, 2018, 55, doi: 10.3389/fmats.2018.00055

[2] Gabriūnaitė I. et al., Electrochim. Acta, 2018, 1351-1358, doi: 10.1016/J.ELECTACTA.2018.04.160.

[3] Liustrovaite V. et al., J. Electrochem. Soc., 2021, 1945-7111, doi: 10.1149/1945-7111/AC0262.