Algal fluorescence sensor integrated into a microfluidic chip for water pollutant detection.

Area of Science:

• Environmental Science
• Biotechnology
• Materials Science

Background:

• Algal fluorescence is a key indicator for assessing environmental pollutant toxicity.
• Miniaturized sensors are needed for efficient and sensitive environmental monitoring.
• Existing methods for detecting herbicide toxicity can be cumbersome and less sensitive.

Purpose of the Study:

• To develop a miniaturized, integrated fluorescent sensor for detecting algal fluorescence.
• To evaluate the sensor's capability in assessing the toxicity of environmental pollutants, specifically herbicides.
• To demonstrate the sensor's sensitivity and efficacy using a model organism and toxicant.

Main Methods:

• Integration of an organic light-emitting diode (OLED) as an excitation source and an organic photodetector (OPD) within a microfluidic chip.
• Development and incorporation of excitation and emission color filters using acid/base dyes and a metal complex.
• Fabrication of the organic photodetector using a PTB3/PC(61)BM blend.
• Assembly of the system within a polydimethylsiloxane (PDMS) microfluidic chip.
• Detection of algal chlorophyll fluorescence to assess pollutant toxicity.

Main Results:

• The developed sensor successfully detected the toxic effects of the herbicide Diuron on Chlamydomonas reinhardtii green algae.
• The sensor achieved a 50% inhibition concentration (EC50) as low as 11 nM for Diuron.
• This represents the first miniaturized fluorescent sensor utilizing algae, OLEDs, and OPDs on a microfluidic chip.

Conclusions:

• The entirely organic bioassay is a sensitive and effective tool for detecting the toxic impact of herbicides on algae.
• This technology offers a promising platform for environmental monitoring of agricultural run-off pollutants.
• The miniaturized sensor design enables efficient and low-concentration toxicity assessments.