Assessing fresh water acute toxicity with Surface-Enhanced Raman Scattering (SERS)

• Published in: Talanta (Oxford) Vol. 267; p. 125163
• Main Authors: Gao, Weixing, Fan, Wanli, Wang, Dongmei, Sun, Ji, Li, Yong, Tang, Changyu, Fan, Meikun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2024
• Subjects: acute toxicity; benzoquinones; bioavailability; Biosensor; Escherichia coli; Escherichia coli (E. coli); freshwater; hydroquinone; p-benzoquinone (BQ); sodium chloride; Surface-Enhanced Raman scattering (SERS); Toxicity; toxicity testing; water quality; Surface-Enhanced Raman scattering (SERS); p-benzoquinone (BQ); Toxicity; Biosensor; Escherichia coli (E. coli)
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2023.125163

It's well known that the toxicity of chemicals in the environment depends not only their concentrations, but more importantly, their bio-availability. Thus, the acute toxicity test of environmental water samples is of great importance in water quality evaluation. In this work, water acute toxicity was determined via SERS approach for the first time based on the reaction between Escherichia coli (E. coli) and p-benzoquinone (BQ). The E. coli was used as the subject of toxicity assay. Under normal conditions, the BQ molecules can be transformed into Hydroquinone (HQ) by the E. coli bacteria; subsequently, the BQ will continue to react with the resulting HQ to form Quinone hydroquinone (QHQ). This process could be impaired in the presence of many toxic chemicals. Bromide modified Ag NPs was then introduced for the highly sensitive SERS detection of the product (HQ and QHQ). Several key factors that may affect water acute toxicity evaluation have been explored, which include the initial BQ and E. coli concentration, the incubation time with BQ, and the sodium chloride concentration. Later, the established system was applied for the toxicity evaluation of Cu2+. It was found that the IC50 value of Cu2+ was 0.94 mg/L, which is superior compared with literature report. This study provides a promising SERS method for assessing acute toxicity in water bodies with high sensitivity and short detection time. We present for the first time a SERS based microbial sensor for assessing acute freshwater toxicity. E. coli and BQ were selected as model microorganisms and SERS probes to evaluate the acute toxicity of Cu2+. The introduction of KBr-modified SERS substrate effectively amplified the weak signal of the reduced products, makes it possible for SERS monitoring the respiration process of e coli using BQ as probe. Factors that potentially affect the toxicity evaluation using e coli were examined with orthogonal experiment. In addition, the simulated toxicants (Cu2+) in water were evaluated, and the IC50 was found to be 0.94 mg/L, which is lower than literature report, suggesting superior performance of the proposed SERS based water acute toxicity assay. [Display omitted] •A SERS biosensor for water acute toxicity evaluation was proposed and validated.•The sensor performance was verified in the real sample of Cu2+.•The factors affecting the final toxicity inhibition rate were explored, and a detection strategy for acute toxicity in water bodies was established.•The toxicity of the simulated toxicant Cu2+ was determined and its IC50 = 0.94 mg/L was obtained.