Combining microfluidics and optics to monitor natural waters

Natural waters – including oceans, lakes, seas, and rivers – are vital for life on earth and yet often inadequately measured or sampled due in no small part to the difficulty and cost of accessing open water for manual sampling. Water monitoring is thus a key target area for the development of in-situ autonomous biogeochemical sensors. In this presentation I will discuss two sets of technology targeted at this application.

The first (based on my PhD work at the Eindhoven University of Technology) is device for sorting and classifying the species of individual phytoplankton cells. The core of the technology is a glass chip machined with femtosecond lasers to form a microchannel and an optical waveguide. Inertial microfluidic forces and optofluidic measurements allow the sorting and classification of individual cells in a mixed population.

Second, for several years the National Oceanography Centre in Southampton has been developing state-of-the-art chemical sensors designed to autonomously perform in situ measurements down to full ocean depths. By taking advantage of the low reagent and power consumption achievable with microfluidics and optical measurements, these sensors can be – and have been – deployed for months at a time in a wide range of settings. I’ll give an overview of the current state of the technology platform, which has been implemented to measure a wide range of chemical parameters including nitrate, phosphate, pH, and show data from some recent deployments. I’ll discuss some of the challenges faced, lessons learned, and future plans for the technology.