Miniaturized sensor system for continuous soil-nutrient monitoring based on integration of a lab-on-a-chip microfluidic cartridge with an optoelectronic detection unit

Introduction

The soil of the earth is the basis of our life. Efficient use of soil is needed for feeding the growing population. Contaminated soil needs to be regenerated to protect the quality of drinking water and, more generally, the ecosystem.

Project Proposal

Here, we propose a highly miniaturized sensor system for monitoring nitrate, ammonium, and phosphate based on the integration of a lab-on-a-chip microfluidic cartridge with an optoelectronic detection unit.

Optoelectronic Detection

The optoelectronic detection chip employs the directional organic light-emitting diode (OLED) we developed within the ERC PoC project BEAMOLED. This kind of OLED allows for direct integration of the optoelectronic chip with the microfluidic cartridge, providing a new level of miniaturization of the optical readout measurement system.

Colorimetric Assays

We propose the use of colorimetric assays based on starting with standard assays and improving performance using nanozyme catalysis. A hydrophilic ceramic as an inlet to a microfluidic channel is proposed for the intake of soil solution. Reagents, as well as the waste, are stored in the sensor system.

System Specifications

We target a system size of 3 cm x 3 cm x 5 cm for maintenance-free operation in the soil for a duration of one year for in-situ monitoring of 100 data points per nutrient.

Scientific Validation

In a soil-science study, the soil-solution extraction into the microfluidic will be investigated for soils with a wide range of pore size distributions, bulk densities, pore-space connectivity, and soil water content to validate the extraction approach scientifically.

Application Testing

Pot and field tests in agriculture and soil remediation are planned for validation in application-relevant environments of two potential markets and to develop market readiness.

Future Plans

Our aim is to start a spin-off company after the completion of this project. By the parallel development of the technology and business side with an interdisciplinary team from electrical engineering, chemical engineering, soil science, and economics/entrepreneurship, an iterative adjustment process is achieved.