Yosi Shacham-Diamand

A Novel Microfluidic Whole Cell Biosensor Based on Electrochemical Detection for Water Toxicity Analysis

Over the last few years, the physical dimensions of microchip devices have decreased, enhancing the interest in the integration of various devices and complex operations onto a compatible lab on a chip system with desirable characteristics and capabilities. This work presents a novel μ-fluidics whole cell biosensor for water toxicity analysis. The biosensor is based on bacterial cells genetically tailored to generate an electrochemical bio-signal in the presence of toxic materials. The μ-chip was electrochemically characterized, and demonstrated the potential toxicity analysis with a model toxicant. A novel concept of bacterial biosensors deposition by means of electrophoretic force was examined for the first time. Preliminary results demonstrated the ability to detect electrochemical signal generated by the deposited bacterial cells indicating the potential use for patterning of bacterial cells on solid-state surfaces for the use in bio-sensing.

Flexible Electrochemical Biochip Array of Patterned Gold on Silver Inkjet Printed Polyimide

Flexible electrodes for bio-electrochemical sensing were fabricated using state-of-the-art inkjet printing followed by two consecutive gold plating steps. Silver nanoparticle printed thin film (1.5μm thick) was sintered at 300°C for 30 minutes and used as seed for the electroless plating of gold (2μm). A further gold electroplating layer was then applied allowing good electrode properties overcoming the printed film roughness and porous morphology which the electroless plating step could not fully cover. The various layers as well as their composite were investigated using electrical, electrochemical and analytical techniques. Eventually, the final electrode was tested with a 3-electrodes setup in a chronoamperometric experiment to detect the Alkaline Phosphatase enzyme in presence of its substrate, ρ-Aminophenyl Phosphate. The electrodes demonstrated a sensitivity of 11.8μA/mM and a limit of detection of 0.9mM.