RA1A: REPORT: Zoospore BioSensor Electronics

Project Summary NRT Tools - Zoospore BioSensor Electronics Report.

March 2024

Helps R, Stephens L. 2024. Project Summary NRT Tools - Zoospore BioSensor Electronics Report. 54 p. Confidential Report

NOTE

This report is not available online. Please contact Dr. Marion Wood to request further details: Marion.Wood@plantandfood.co.nz

ABSTRACT

This technical report summarises the development activities performed by InFact Ltd for the Ngā Rākau Taketake (NRT) Programme. This centred around the development of specialised electronics for the detection of phytophthora zoospores within a microfluidic device.

inFact facilitated a design thinking workshop focusing on how on to progress the research from a lab tool to a field tool. The team identified primary device requirements and challenges and developed concept designs for a field-based device, which influenced the microfluidic device design.

The underlying concept for the zoospore detection system is that the electrical impedance between electrodes located across a micro-channel will change slightly as a zoospore passes through the channel. A lock-in amplifier (LIA) was used to detect and measure weak narrow-band signals contained within large amounts of electromagnetic interference and electrical noise. Initial testing was based on a LIA development kit, which was evaluated and optimised. Design improvements were identified, including increasing amplifier gain and improving mains interference rejection which were embodied in a bespoke, battery powered portable electronics platform for improved zoospore detection device.

Supporting mounting platforms, hardware and cabling solutions were developed that allowed experimental setup to be tested and evaluated by Plant and Food Research and the University of Auckland. Testing showed that the system could successfully detect zoospores.