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Proceedings Paper

Control over capacitive and Faradaic extracellular photostimulation of neurons using intermediate ZnO layer for organic bio-interfaces (Conference Presentation)

Paper Abstract

Biointerfaces based on photovoltaic substrates has gained substantial attention for neural photostimulation[1, 2]. The control of Faradaic and capacitive charge transfer mechanisms by these substrates is important for effective and safe photostimulation of neurons. Faradaic mechanism uses charge transfer between electrode and electrolyte with oxidation and reduction reactions, and capacitive mechanism electrostatically perturb local ion concentration in the electrode/electrolyte interface[3, 4]. In this study, we show the control of light-activated Faradaic and capacitive charge transfer mechanisms by bulk heterojunction photovoltaic biointerfaces. We tuned the strength of the mechanisms via spatial control of the photogenerated electrons and holes in the biointerface architecture. For that, we explored three different architectures (Fig. 1) using intermediate ZnO and MoOx layers and without any intermediate layer between the transparent metal oxide (ITO) and photoactive layer. The photoactive layer is composed of organic-inorganic ternary blend of poly(3-hexylthiophene-2,5-diyl (P3HT), [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) and PbS quantum dots that lead to strong displacement currents. Moreover, we observed that integration of PbS quantum dots in the active blend of P3HT:PCBM enhances both capacitive and faradaic photocurrents due to well-aligned energy diagram, stronger absorption and better surface morphology. To characterize the photostimulation, we seeded SHSY-5Y cells on our biointerfaces and recorded the membrane depolarization of single cells. The results are also supported by two-domain stimulation model[4, 5].

Paper Details

Date Published: 10 March 2020
PDF
Proc. SPIE 11255, Colloidal Nanoparticles for Biomedical Applications XV, 112550N (10 March 2020); doi: 10.1117/12.2545571
Show Author Affiliations
Rustamzhon Melikov, Koç Univ. (Turkey)
Shashi Bhushan Srivastava, Koç Univ. (Turkey)
Mohammad Mohammadi Aria, Koç Univ. (Turkey)
Ugur Meric Dikbas, Koç Univ. (Turkey)
Ibrahim Halil Kavakli, Koç Univ. (Turkey)
Sedat Nizamoglu, Koç Univ. (Turkey)


Published in SPIE Proceedings Vol. 11255:
Colloidal Nanoparticles for Biomedical Applications XV
Marek Osiński; Antonios G. Kanaras, Editor(s)

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