Towards pharmacological treatment screening of cardiomyocyte cells using Si nanowire FETs.

Silicon nanowires (Si NWs) are the most promising candidates for recording biological signals due to improved interfacing properties with cells and the possibility of high-speed transduction of biochemical signals into detectable electrical responses. The recording of extracellular action potentials (APs) from cardiac cells is important for fundamental studies of AP propagation features reflecting cell activity and the influence of pharmacological substances on the signal. We applied a novel approach of using fabricated Si NW field-effect transistors (FETs) in combination with fluorescent marker techniques to evaluate the functional activity of cardiac cells. Extracellular AP signal recording from HL-1 cardiomyocytes was demonstrated. This method was supplemented by studies of the pharmacological effects of stimulations using noradrenaline (NorA) as a modulator of functional activity on a cellular and subcellular levels, which were also tested using fluorescent marker techniques. The role of calcium alteration and membrane potential were revealed using Fluo-4 AM and tetramethylrhodamine, methyl ester, perchlorate (TMRM) fluorescent dyes. In addition, chemical treatment with sodium dodecyl sulfate (SDS) solutions was tested. The results obtained demonstrate positive prospects for AP monitoring in different treatments for studies related to a wide range of myocardial diseases using lab-on-chip technology.

Liquid-Gated Two-Layer Silicon Nanowire FETs: Evidence of Controlling Single-Trap Dynamic Processes.

We fabricate two-layer (TL) silicon nanowires (NW) field-effect transistors (FETs) with a liquid gate. The NW devices show advanced characteristics, which reflect reliable single-electron phenomena. A strong modulation effect of channel conductivity with effectively tuned parameters is revealed. The effect opens up prospects for applications in several research fields including bioelectronics and sensing applications. Our results shed light on the nature of single trap dynamics which parameters can be fine-tuned to enhance the sensitivity of liquid-gated TL silicon nanowire FETs.

Noise spectroscopy of tunable nanoconstrictions: molecule-free and molecule-modified.

Devices with metallic nanoconstrictions functionalized by organic molecules are promising candidates for the role of functional devices in molecular electronics. However, at the moment little is known about transport and noise properties of nanoconstriction devices of this kind. In this paper, transport properties of bare gold and molecule-containing tunable cross-section nanoconstrictions are studied using low-frequency noise spectroscopy. Normalized noise power spectral density (PSD) S I /I 2 dependencies are analyzed for a wide range of sample resistances R from 10 Ohm to 10 MOhm. The peculiarities and physical background of the flicker noise behavior in the low-bias regime are studied. It is shown that modification of the sample surface with benzene-1,4-dithiol molecules results in a decrease of the normalized flicker noise spectral density level in the ballistic regime of sample conductance. The characteristic power dependence of normalized noise PSD as a function of system resistance is revealed. Models describing noise behavior for bare gold and BDT modified samples are developed and compared with the experimental data for three transport regimes: diffusive, ballistic and tunneling. Parameters extracted from models by fitting are used for the characterization of nanoconstriction devices.

Effect of Gamma Irradiation on Dynamics of Charge Exchange Processes between Single Trap and Nanowire Channel.

In the present study, transport properties and single trap phenomena in silicon nanowire (NW) field-effect transistors (FETs) are reported. The dynamic behavior of drain current in NW FETs studied before and after gamma radiation treatment deviates from the predictions of the Shockley-Read-Hall model and is explained by the concept taking into account an additional energy barrier in the accumulation regime. It is revealed that dynamics of charge exchange processes between single trap and nanowire channel strongly depend on gamma radiation treatment. The results represent potential for utilizing single trap phenomena in a number of advanced devices.