Integrated dual nanoprobe-microfluidic system for single cell electrical property characterizations

Abstract

This thesis presents the simulation of an integrated dual nanoprobe-microfluidic system for single cell electrical characterizations. Recent cell studies have shown a possible early disease diagnosis at a single cell level by characterizing its electrical properties. One of the studies uses a dual nanoprobe showing its ability in quantitatively detecting single cell viability. However, this method has low through put rate, high skilled labour requirement and bulky system. We propose an improved system that overcomes these limitations. This study is divided into five stages. The first stage focuses on deciding the system concept and nanoprobe design.The second stage involves nanoprobe characterization which is based on electrical and mechanical properties of five different materials: Silver, Copper, Aluminium,Tungsten and Zinc. The third stage is a single cell modeling of Saccharomycescerevisiae for mechanical and electrical model. The fourth stage is nanoprobe integration with microfluidic system. The final stage is single cell electrical property characterizations. From the study, several findings were obtained and concluded.First, the most preferred material for nanoprobe is Tungsten which has low electrical resistance of 5.5 Ω and can withstand an external force up to 35.6 μN before failure.Second, the two layers cell model was validated by displaying a close agreement interms of penetration force (640 nN) with experimental data. Third, successful cell penetration was achieved at 5.1 pl/min flow rate in 4 μm diameter micro channel.Lastly, insulating the nanoprobe reduces the effect of penetration depth on the current measurement and enables the characterization of single cell cytoplasm electrical conductivity to be realized. Currently the developed system is suitable for cell viability detection application. Furthermore, this system has a potential to be used in single cell thermal measurement, single cell drug delivery and early disease diagnosis.