Electrochemical biosensors currently dominate the field, but are focussed mainly on metabolite monitoring, while bio-affinity monitoring is carried out principally using optical techniques. However, both transducers find utility across the whole field, along with piezoelectric, thermometric, magnetic and micro-mechanical transducers. The emergence of semi-synthetic and synthetic receptors is yielding more robust, versatile and widely applicable sensors, while nano-materials are facilitating highly sensitive and convenient transduction of the resulting binding and catalytic events. Few if any sensoring devices incorporate living substrates because it is very difficult to keep the living substrate (e.g. micro-organisms, cell cultures, tissue) functioning in a non-sterile environment with a bandwidth of supporting devices. We proposed to develop a slime mould based sensor as the only ever marketable bio-sensor with living substrate which does not require sophisticated maintenance and can be operated by anyone.
Biosensor technology is based on a specific biological recognition element in combination with a transducer for signal processing. Since its inception, biosensors have been expected to play a significant analytical role in medicine, agriculture, food safety, homeland security, environmental and industrial monitoring. However, the commercialisation of biosensor technology has significantly lagged behind the research output as reflected by a plethora of publications and patenting activities. The rationale behind the slow and limited technology transfer could be attributed to cost considerations and some key technical barriers. Analytical chemistry has changed considerably, driven by automation, miniaturisation, and system integration with high throughput for multiple tasks. Such requirements pose a great challenge in biosensor technology which is often designed to detect one single or a few target analytes. Successful biosensors must be versatile to support interchangeable bio-recognition elements, and in addition miniaturisation must be feasible to allow automation for parallel sensing with ease of operation at a competitive cost. A significant upfront investment in research and development is a prerequisite in the commercialisation of biosensors. The progress in such endeavours is incremental with limited success, thus, the market entry for a new venture is very difficult unless a niche product can be developed with a considerable market volume.
Our goal was to manufacture, market and support open source an open hardware very low cost universal (chemical, tactile, optical) bio-sensor incorporating easy-to-maintain living substrate -- slime mould Physarum polycephalum. The Physarum sensors is based on exhaustive analysis of the slime mould oscillatory activity in PhyChip project. The goal was achieved via the following measurable objectives:
(1) Pre-production prototype, (2) Field trial with typical operators, (2) Robust data set in the matrices of interest.
