Droplet microfluidic based sensors for high resolution chemical sensing on autonomous underwater vehicles
Lead Research Organisation:
University of Southampton
Department Name: Faculty of Engineering & the Environment
Abstract
Chemical processes within the oceans underpin the planet's natural cycles of life. Marine ecology, for example, depends on where and in what quantity nutrients (such as nitrate and phosphate) are transported, as these constitute the ultimate base of the food chain. The oceans are also in dynamic equilibrium with the atmosphere and are intrinsic to how the world will adjust to the effects of anthropogenic carbon dioxide. Thus better understanding of oceanic chemical dynamics is not only of academic interest, but will also lead to better protection of marine life and improved models to understand and predict climatic change.
To properly understand ocean chemistry, however, we must be able to accurately measure the temporal and spatial distributions of chemical species within the environment and how they change in response to different stimuli. The vastness of the oceans provides a logistical problem however - how can we possibly characterise such a large and complex body of water? One compelling answer to this is to employ autonomous underwater vehicles (AUVs) equipped with chemical sensors. AUVs can travel to remote locations for months at a time without need of human interaction and as such offer a highly efficient way to gather information about the chemical dynamics of the ocean.
The current state-of-the-art chemical sensors (which automatically sample and analyse the water using miniaturised laboratory assays) provide superlative analytical performance (accuracy, precision, sensitivity) but suffer from inefficient use of resources (power, fluid) and low measurement frequencies - limiting their applicability to AUVs. In response to this, during this fellowship I will develop a new type of chemical sensor based around droplet microfluidics. Droplet microfluidics involves the generation, manipulation and measurement of discrete droplets of water dispersed within a stream of oil flowing along tubing hundreds of microns in width. As the droplet volumes are so small (sub-microlitre), chemical treatments and measurements can be quickly and precisely performed, meaning droplet microfluidics offers a rapid and highly efficient route to continuous sampling and chemical analysis of the environment.
While droplet microfluidics is a proven and widely used tool for laboratory-based analytical chemistry, it is only now making its way into the first field-deployable devices. In this fellowship I will drive improvements in the sensitivity, measurement frequency and applicability of field-deployable droplet microfluidics to develop droplet microfluidic sensors suitable for use on AUVs. The sensors will be highly efficient (low power and fluid use), capable of measuring several different chemical parameters with high sensitivity (meaning they can be used in a wide range of marine environments) and at high measurement frequencies (which translates into richly detailed spatial data when used on moving vehicles). This project will be a key step towards the widespread, routine usage of sensors to monitor chemical change in the marine environment, in particular on AUVs. It will lead to chemical sensors being a ubiquitous tool in environmental science in the future, eventually deployed in large volumes throughout the oceans on static moorings and ocean-going autonomous vehicles.
To properly understand ocean chemistry, however, we must be able to accurately measure the temporal and spatial distributions of chemical species within the environment and how they change in response to different stimuli. The vastness of the oceans provides a logistical problem however - how can we possibly characterise such a large and complex body of water? One compelling answer to this is to employ autonomous underwater vehicles (AUVs) equipped with chemical sensors. AUVs can travel to remote locations for months at a time without need of human interaction and as such offer a highly efficient way to gather information about the chemical dynamics of the ocean.
The current state-of-the-art chemical sensors (which automatically sample and analyse the water using miniaturised laboratory assays) provide superlative analytical performance (accuracy, precision, sensitivity) but suffer from inefficient use of resources (power, fluid) and low measurement frequencies - limiting their applicability to AUVs. In response to this, during this fellowship I will develop a new type of chemical sensor based around droplet microfluidics. Droplet microfluidics involves the generation, manipulation and measurement of discrete droplets of water dispersed within a stream of oil flowing along tubing hundreds of microns in width. As the droplet volumes are so small (sub-microlitre), chemical treatments and measurements can be quickly and precisely performed, meaning droplet microfluidics offers a rapid and highly efficient route to continuous sampling and chemical analysis of the environment.
While droplet microfluidics is a proven and widely used tool for laboratory-based analytical chemistry, it is only now making its way into the first field-deployable devices. In this fellowship I will drive improvements in the sensitivity, measurement frequency and applicability of field-deployable droplet microfluidics to develop droplet microfluidic sensors suitable for use on AUVs. The sensors will be highly efficient (low power and fluid use), capable of measuring several different chemical parameters with high sensitivity (meaning they can be used in a wide range of marine environments) and at high measurement frequencies (which translates into richly detailed spatial data when used on moving vehicles). This project will be a key step towards the widespread, routine usage of sensors to monitor chemical change in the marine environment, in particular on AUVs. It will lead to chemical sensors being a ubiquitous tool in environmental science in the future, eventually deployed in large volumes throughout the oceans on static moorings and ocean-going autonomous vehicles.
People |
ORCID iD |
Adrian Nightingale (Principal Investigator / Fellow) |
Publications
Bhuiyan W.T.
(2021)
AN IN SITU DROPLET MICROFLUIDICS BASED AMMONIUM SENSOR AND ITS APPLICATION TO A SEQUENTIAL BATCH BIOREACTOR
in MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences
Clark M
(2024)
3D printed filtration and separation devices with integrated membranes and no post-printing assembly
in Reaction Chemistry & Engineering
Elvira KS
(2022)
Materials and methods for droplet microfluidic device fabrication.
in Lab on a chip
Lu B
(2024)
Droplet Microfluidic-Based In Situ Analyzer for Monitoring Free Nitrate in Soil.
in Environmental science & technology
Lu B.
(2021)
Sensitive absorbance measurement in droplet microfluidics via multipass flow cells
in MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences
Nightingale A.M.
(2019)
A droplet microfluidic-based sensor for monitoring river nitrate/nitrite concentrations
in 23rd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2019
Nightingale A.M.
(2021)
DROPLET-ON-DEMAND AT POINT OF SAMPLING
in MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences
Nightingale A.M.
(2020)
Easily-fabricated fluoropolymer chips for sensitive long-term absorbance measurement in droplet microfluidics
in MicroTAS 2020 - 24th International Conference on Miniaturized Systems for Chemistry and Life Sciences
Nightingale AM
(2020)
Easily fabricated monolithic fluoropolymer chips for sensitive long-term absorbance measurement in droplet microfluidics.
in RSC advances
Nightingale AM
(2019)
A Droplet Microfluidic-Based Sensor for Simultaneous in Situ Monitoring of Nitrate and Nitrite in Natural Waters.
in Environmental science & technology
Description | The knowledge exchange with partner SME has contributed to the maturing of their sensor technology with droplet-based nitrate and nitrite sensors being their first commercial product in 2019. Phosphate and ammonium sensors are in development. |
First Year Of Impact | 2019 |
Sector | Environment,Manufacturing, including Industrial Biotechology |
Impact Types | Economic |
Description | Decoding Nitrogen Dynamics in Soil through Novel Integration of in-situ Wireless Soil Sensors with Numerical Modeling |
Amount | £569,433 (GBP) |
Funding ID | NE/T010584/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 01/2020 |
End | 12/2025 |
Description | UK-Further development of droplet microfluidic based chemical sensors for rapid measurement of nutrients in water |
Amount | £124,847 (GBP) |
Funding ID | NE/S013458/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 06/2019 |
End | 08/2020 |
Description | Collaboration with ecoSub |
Organisation | Planet Ocean |
Country | United Kingdom |
Sector | Private |
PI Contribution | Development of prototype water sampling technology. |
Collaborator Contribution | Technical consultancy |
Impact | Prototype water sampling technology for ecoSub autonomous underwater vehicles which will be tested in future years. |
Start Year | 2022 |
Description | Collaborative sensor development and deployment work with SouthWestSensor Ltd |
Organisation | SouthWestSensor Ltd |
Country | United Kingdom |
Sector | Private |
PI Contribution | Time spent analysing data on collaborative sensor deployments. Informal consultancy. |
Collaborator Contribution | Informal consultancy on electronic and mechanical engineering. Time spent deploying sensors on collaborative deployments. |
Impact | DOI:10.1021/acs.est.9b01032 |
Start Year | 2018 |
Description | Provision of droplet-microfluidic experimental demonstration for "Pint of Science" talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | As part of the "Pint of Science" event, Dr Jonathan West gave a talk on microfluidics ("The Shape of Water") at the Steingarten in Southampton on Mon 14th May. I provided a practical demonstration of droplet microfluidics, based on the technology I am developing in this grant. |
Year(s) Of Engagement Activity | 2018 |