A Fast and Easily Parallelizable Biosensor Method for Measuring Extractable Tetracyclines in Soils

Abstract

Quantification of extractable antibiotics in soils is important to assessing their bioavailability and mobility, and ultimately their ecotoxicological and health risks. This study aimed to establish a biosensor method for detecting extractable tetracyclines in soils (Alfisol, Mollisol, and Ultisol) using whole-cell biosensors containing a reporter plasmid (pMTGFP or pMTmCherry) carrying fluorescent protein genes tightly controlled by tetracyclines-responsive control region (tetRO). This whole-cell biosensor method can simultaneously measure 96 or more samples within 6 h and is easily parallelizable, whereas a typical high-performance liquid chromatography (HPLC) method may require 7 times more of analysis time and much greater cost to achieve similar analytical throughput. The biosensor method had a detection limit for each of six tetracyclines between 5.32−10.2 μg/kg soil, which is considered adequate for detecting tetracyclines in ethylenediaminetetraacetic acid (EDTA) extracts of soils. Relative standard deviation was between 19.8−51.2% for the biosensor Escherichia coli DH5α/pMTGFP and 2.98−25.8% for E. coli DH5α/pMTmCherry, respectively, suggesting that E. coli DH5α/pMTmCherry was superior to E. coli DH5α/pMTGFP for detecting extractable tetracyclines in soils. This new, fast, easily parallelizable, and cost-effective biosensor method has the potential for measuring extractable concentrations of tetracyclines for a large number of soil samples in large-scale monitoring studies.

Whole-cell paper strip biosensors to semi-quantify tetracycline antibiotics in environmental matrices

“…In this study, the construction of Escherichia coli/pMTLacZ for whole-cell biosensor was similar to that of Escherichia coli/pMTGFP and Escherichia coli/pMTmcherry from our previous study (Ma et al 2020). These cellular reporters can rapidly and accurately detect tetracyclines in water or soil.…”

“…This paper strip biosensor could serve as a simple and economical portable piece of field kit for on-site monitoring of AHLs in various types of environmental samples. So far, the efficacy of these antibiotic biosensors have only been demonstrated in preliminary research for the detection of antibiotics in water and soils under laboratory conditions (Ma et al 2020). Studies on antibiotic colorimetric strips using whole-cell biosensors for on-site semiquantitative visual testing are not available.…”

Recent Advances in Chemical Sensors for Soil Analysis: A Review

“…Reviews on chemical sensors and biosensors for antibiotic detection in food and the environment were previously published by Lakshmi et al [217] and Sun et al [218]. In [219] a whole-cell (Escherichia coli) fluorescent biosensor for detecting extractable tetracyclines in soils (Alfisol, Mollisol, and Ultisol) using a reporter plasmid (pMTGFP or pMTmCherry) carrying fluorescent protein genes was developed. The developed biosensor had a detection limit for tetracyclines between 5.32 and 10.2 µg/kg soil, and was seven times faster than a typical high-performance liquid chromatography (HPLC) method; and it was shown to be a promising, cost-effective method for measuring extractable concentrations of tetracyclines in a great number of soil samples in large-scale monitoring studies.…”

Test-strip and smartphone-assisted Eu-TCPE-based ratiometric fluorescence sensor for the ultrasensitive detection of tetracycline

“…3,4 Moreover, the TC residues in the environment can lead to bacterial resistance to antibiotics. 5 Therefore, it is of great urgency to establish sensitive, intuitive, and real-time sensing platforms for the monitoring of TC concentrations in water and food samples.…”