Question

1. Design a pheromone sensor.

2. Design a taste sensor.

Answer 1

Designing of a pheromone sensor

Biosynthetic Pheromone Emission The artificial pheromone-emitter gland is driven by a syringe pump and an evaporation controller system used to control a micromachined evaporator for the release of pheromone into the chamber. This artificial gland imitates the functionality of the biological mechanism that allows the moth S. littoralis to release pheromones in specific dosing. Chemoemitter is crucial for the labeling of information before they are transmitted into the real world based on relative proportions between compounds . As the normal solution of pheromone Z,E-9,11- 14:OAc is highly concentrated, hexane was used as the solvent for diluting the pheromone. The microevaporator temperature was set to a temperature of 90°C and different volumes of this pheromone solution was delivered to the chip by a syringe pump at a flow rate of 5 µL/sec, in order to input the odour stimulus into the wind tunnel.

Chemoreception using SAWR Sensors A highly-sensitive (ppb level), polymer-coated RF-based SAWR oscillator array was employed to detect the semiochemical concentrations in the gas phase, which electronically simulates the complex olfactory system of the night-active insects. More specifically, the SAWR sensor array mimics the insect’s antenna with different types of sensilla designed for detection of various olfactory stimuli . The SAW resonator based sensors are not only highly sensitive, but also simpler in operation having only frequency output and so require a much simpler interface circuitry for data processing.

The SAWR sensors were driven by amplifier based independent feedback-oscillator circuits consisting of surface mount amplifiers, a low pass filter, and the buffer circuitry. The oscillator Printed Circuit Board (PCB) is a four layer board with separate grounding planes which takes account of the phase shifts associated with the RF signal path within the resonatorcircuitry loop. It also reduces the RF cross talk, thereby improving noise sensitivity.

Designing of a taste sensor

The lipid/polymer membrane was modified by using Gold nanoparticles and Quantum dots. The

synthesis process of the nanoparticles is described as follows

Gold nano-particles were synthesized using the citrate method following the procedure described

below: An aqueous solution of Gold nano-particles (AuNPs) was prepared by reducing

tetrachloroauric acid (HAuCl4) with glutamic acid under refluxing to yield colloidal gold

Mix 200mg TDAB (Lipid) in 1mL THF with proper stirring and sonicate it for about

two minutes to make a homogeneous solution.

Take 0.5mL of lipid solution and add 310μL of DOPP (Plasticizer) so that 1:3 Lipid:

Plasticizer ratio is obtained.

Mix the above mixture in 9.4mL THF and then sonicate it for two minutes.

Then, Add calculated amount of PVC (Solvent) -200mg to the solution so as to obtain

1:2:3 ratio of Lipid: Polymer: Plasticizer and sonicate it for ten minutes.

Transfer this solution to flat bottom (Petri plate/Glass plate) and leave for aging

(overnight/24 hours).

A thin-soft-transparent-colorless film of approximately 200μm thickness will be

obtained.

Use the Lipid membrane obtained as Sweetness Taste Sensor.