Lab-on-chip technology for in situ determination of dissolved organic nutrients

This proposal addresses a critical technology gap: dissolved organic nutrients cannot with current technology be measured routinely in situ. This is despite their importance in the cycling of nitrogen and phosphate in the natural environment. These chemicals are essential to plant growth and regulate the production of food at the base of the food chain. They can also act as pollutants through direct toxicity at elevated levels, and by stimulation of unwanted plant or bacterial growth that can lead to eutrophication (causing oxygen depletion and damage in aquatic environments). These processes are important in a wide range of aquatic and terrestrial environments, for studies of environmental change, and for management of natural and anthropogenic (human mediated) processes. This includes but is not limited to land use change, agriculture and aquaculture management, soil impoverishment, erosion, urbanisation, and waste water (human waste) management. The potential impact of a solution includes commercial exploitation of the technology, and a transformative effect on the practice of nutrient measurement for both science and industrial applications. This potential is amplified by recent successes at Southampton in the development of robust, accurate and sensitive instrumentation for determination of dissolved inorganic nutrients in situ based on lab on chip (LOC) technology. The availability of technology for both organic and inorganic forms would enable holistic and accurate assessment of the total nutrient processes.
The project will address this technology gap by developing a device that converts dissolved organic nutrients (which are difficult to measure directly) in inorganic forms that can be readily measured with technology that we have already developed. Both the new and existing technologies will be (are) based on Lab on chip technology which uses fabrication of channels and engineering features on the scale of a tenths of a millimetre to perform complex analytical chemistry. The new device will expose sample water to UV radiation and carefully optimised chemical conditions to convert organic nutrients into inorganic nutrients. The existing device measures the concentration of inorganic nutrients by mixing the sample with chemicals which react and result in a colour change. The intensity of the colour change is proportional to the concentration of the nutrient targetted and is measured electrically using LEDs and optical detectors integrated into our microfluidic device.
Once this technology concept is proved it will be (in subsequent research) further developed into a routinely deployable system for freshwater, groundwater, estuaries and marine environments. This system will be proposed as an important element of a future project in the next round of research undertaken for the NERC macronutrient cycles programme specifically targeting catchment scale monitoring of the Hampshire Avon catchment.

1. The UK economy and hence society (In the medium term (1-3 years)). This will be achieved through employment taxation, and improved services from companies who will financially benefit and gain reputation from the commercial exploitation of the technology in the medium term. This will include multiple organisations in the value chain including manufacturers, distributers, sales organisations, service companies, and environmental consultancies. In the medium term we expect a product to result with licensing with a suitable partner the most likely route to exploitation.
2. Government and hence society (In the medium term (1-3 years)). This will be achieved through improved capability in the monitoring of chemicals of public health, environmental and industrial importance. This will enable better monitoring, understanding of complex systems, management of resources, enforcement and revision of regulations. Key actors in this chain include agencies and regulatory bodies (e.g. the Environment Agency, DEFRA, EU), local government, freshwater and marine scientists, and workers in aquaculture and the waste water and potable water industries. They will benefit in the medium term from the availability of a new generation of metrology platform for analysis of nitrogen and phosphorous. In the short term they will also benefit from knowledge transfer activities to disseminate the skills and technology necessary to realise these benefits.
3. Technologist researchers developing biogeochemical sensors, and also the wider lab on chip community who will gain a device and method for the conversion of organic nutrients into forms more easily accessed by existing inorganic nutrient sensors using lab on a chip technology. This knowledge and technology will form the basis for continued development towards higher technology readiness levels leading to demonstration for in situ deployments in fresh and salt water environments, and subsequent exploitation and mass production. New methods of manufacturing, new designs, and methods of integrating state of the art short wavelength (UV) sources will also enable novelty and improved performance in other applications such wider analytical chemistry, medicine, and industrial process control.
4. The wider technology developing community working in aquatic environments who can use our developments and follow on research as an element of observation systems and sensor networks.
5. Researchers associated with the macronutrient cycles programme who will gain a new capability and knowledge base for in situ measurement of organic nutrients.