Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Highly Sensitive Whole-Cell Mercury Biosensors for Environmental Monitoring

Dahlin Zevallos-Aliaga
ORCID logo ,
Stijn De Graeve
ORCID logo ,
Pamela Obanda-Chávez
,
Nicolás Arias Vaccari
ORCID logo ,
Yue Gao
ORCID logo ,
Tom Peeters
* ORCID logo ,
Daniel Guerra
* ORCID logo
Version 1 : Received: 29 April 2024 / Approved: 29 April 2024 / Online: 29 April 2024 (16:49:55 CEST)

A peer-reviewed article of this Preprint also exists.

Zevallos-Aliaga, D.; De Graeve, S.; Obando-Chávez, P.; Vaccari, N.A.; Gao, Y.; Peeters, T.; Guerra, D.G. Highly Sensitive Whole-Cell Mercury Biosensors for Environmental Monitoring. Biosensors 2024, 14, 246. Zevallos-Aliaga, D.; De Graeve, S.; Obando-Chávez, P.; Vaccari, N.A.; Gao, Y.; Peeters, T.; Guerra, D.G. Highly Sensitive Whole-Cell Mercury Biosensors for Environmental Monitoring. Biosensors 2024, 14, 246.

Abstract

Whole cell biosensors could serve as eco-friendly and cost-effective alternatives for detecting potentially toxic bioavailable heavy metals in aquatic environments. However, they often fail to meet practical requirements due to an insufficient limit of detection (LOD) and high background noise. In this study, we designed a synthetic genetic circuit specifically tailored for detecting ionic mercury, which we applied to environmental samples collected from artisanal gold mining sites in Peru. We developed two distinct versions of the biosensor, each utilizing a different reporter protein: a fluorescent biosensor (Mer-RFP) and a colorimetric biosensor (Mer-Blue). Mer-RFP enabled real-time monitoring of the culture’s response to mercury samples using a plate reader, whereas Mer-Blue was analysed for colour accumulation at the endpoint using a specially designed, low-cost camera set up for harvested cell pellets. Both biosensors exhibited negligible baseline expression of their respective reporter proteins and responded specifically to HgBr2 in pure water. Mer-RFP demonstrated a linear detection range from 1 nM to 1 μM, whereas Mer-Blue showed a linear range from 2 nM to 125 nM. Our biosensors successfully detected a high concentration of ionic mercury in the reaction bucket where artisanal miners produce a mercury-gold amalgam. However, they did not detect ionic mercury in the water from active mining ponds, indicating a concentration lower than 3.2 nM Hg2+ -a result consistent with chemical analysis quantitation. Furthermore, we discuss the potential of Mer-Blue as a practical and affordable monitoring tool, highlighting its stability, reliance on simple visual colorimetry, and the possibility of sensitivity expansion to organic mercury.

Keywords

whole‐cell biosensor; mercury detection; artisanal gold mining; environmental monitoring; bioavailable heavy metals; MerR; Tn501

Subject

Biology and Life Sciences, Biology and Biotechnology

Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Download PDF Download Supplementary

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our Diversity statement.

Leave a public comment
Send a private comment to the author(s)
* All users must log in before leaving a comment
Views 0
Downloads 0
Comments 0
Metrics 0
Get PDF Supplementary Files Cite Share 0
Bookmark BibSonomy Mendeley Reddit Delicious
×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.