Capacitance Contribution of NIH/3T3 Cells Existing on and between Electrodes of an Impedance Biosensor

In this study, an impedance biosensor capable of real-time monitoring of the growth and drug reactions using NIH/3T3 cells was fabricated through a semiconductor process. With the fabricated impedance biosensor, the cell growth and drug reaction states are monitored in real-time, showing the validness of the developed biosensor. By using the developed impedance biosensor, we have investigated the capacitance contribution of NIH/3T3 cells existing on electrodes and between electrodes. To compare the capacitance value contributions of the cells on and between electrodes, wide- and narrow-gap electrode patterns are manufactured with 3.7 and 0.3 mm electrode gap spacings, respectively. From the detailed analysis, the capacitance contributions of NIH/3T3 cells existing on electrodes are estimated around less than 20 percent compared to the cells existing between electrodes. In other words, a minimized electrode area with maximized electrode spacing is the promising impedance biosensor design guide for accurate cell capacitance measurements

Pre-silicidation annealing effect on platinum-silicided Schottky barrier MOSFETs Pre-silicidation annealing effect on platinum-silicided Schottky barrier MOSFETs

Abstract We fabricated platinum-silicided p-type Schottky barrier MOSFETs (SB-MOSFETs) with 40 nm gate length on a silicon-on-insulator wafer. In order to improve the device performance, the devices were annealed at a temperature of 900 • C in a nitrogen environment prior to the platinum deposition for source/drain silicide formation. As a result, lowered threshold voltage of 1.2 V, subthreshold swing values of 110 mV and an enhanced on/off current ratio larger than 10 7 were obtained. This improvement is attributed to the reduction of the fixed oxide charge in the gate oxide during the annealing process

Growth and Drug Interaction Monitoring of NIH 3T3 Cells by Image Analysis and Capacitive Biosensor

Capacitive biosensors are manufactured on glass slides using the semiconductor process to monitor cell growth and cell–drug interactions in real time. Capacitance signals are continuously monitored for each 10 min interval during a 48 h period, with the variations of frequency from 1 kHz to 1 MHz. The capacitance values showed a gradual increase with the increase in NIH 3T3 cell numbers. After 48 h of growth, 6.67 μg/mL puromycin is injected for the monitoring of the cell–drug interaction. The capacitance values rapidly increased during a period of about 10 h, reflecting the rapid increase in the cell numbers. In this study, we monitored the state of cells and the cell–drug interactions using the developed capacitive biosensor. Additionally, we monitored the state of cell behavior using a JuLiTM Br&FL microscope. The monitoring of cell state by means of a capacitive biosensor is more sensitive than confluence measuring using a JuLiTM Br&FL microscope image. The developed capacitive biosensor could be applied in a wide range of bio-medical areas; for example, non-destructive real-time cell growth and cell–drug interaction monitoring