A microfluidic system for viability determination of microalgae upon disinfectant treatment under continuous flow

• Published in: The Science of the total environment 2022-04, Vol.816, p.151615-151615, Article 151615
• Main Authors: Yang, Yamin, Dong, Rui, Zhang, Shu, Geng, Jinfa, Wang, Feilong, Liu, Sijia, Tao, Ling, Li, Weitao, Chen, Chunxiao, Qian, Zhiyu
• Format: Article
• Language: English
• Subjects: Chlorella vulgaris; Disinfectants - toxicity; Ecosystem; Ecotoxicity evaluation; Laser speckle contrast imaging; Microalgae; Microfluidic; Microfluidics; Quaternary ammonium compounds
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.151615

The extensive use of quaternary ammonium compounds (QACs) has raised concerns regarding their environmental fate and potential risks to the ecosystem. As sensitive pollution indicators, green microalgae could readily monitor the aquatic toxicity of QACs as reflective of the changes in cell viability. Recent microfluidic-based systems have been designed for environmental biomonitoring and ecotoxicity studies while overall information of cell viability cannot be directly visualized under flowing conditions. In the present study, we developed a multifunctional microfluidic platform with the integration of analytical techniques including laser speckle contrast imaging and fluorescence spectroscopy for monitoring algal activity in response to QAC treatment. The biocidal efficiency of a representative QAC benzalkonium bromide (BAB) on a typical aquatic algae Chlorella vulgaris was determined by collecting the bio-speckles and chlorophyll autofluorescence in real-time, where dose-dependent and time-dependent decrease of algal growth was found with the increase of BAB concentration and interaction time. The integrated system was capable of rapid detection of the aquatic toxicity of QACs along with macroscopical visualization of algal activities under flowing conditions in time-course, which could be extended to future implementation for broad ecotoxicity analysis of versatile environmental samples. [Display omitted] •A microfluidic system was developed for the ecotoxicological evaluation of quaternary ammonium compounds.•Algal response to disinfectants was determined by collecting the chlorophyll autofluorescence under flowing conditions.•Changes of cell viability were visualized by laser speckle contrast signals in the integrated system.•This methodology could extend to broader ecotoxicity analysis under versatile environmental scenarios.