Preprint Article Version 1 Preserved in Portico This version is not peer-reviewed

Portable FRET-Based Biosensor Device for On-Site Lead Detections

Version 1 : Received: 26 January 2022 / Approved: 26 January 2022 / Online: 26 January 2022 (14:49:25 CET)
Version 2 : Received: 23 February 2022 / Approved: 23 February 2022 / Online: 23 February 2022 (10:53:14 CET)

A peer-reviewed article of this Preprint also exists.

Lai, W.-Q.; Chang, Y.-F.; Chou, F.-N.; Yang, D.-M. Portable FRET-Based Biosensor Device for On-Site Lead Detection. Biosensors 2022, 12, 157. Lai, W.-Q.; Chang, Y.-F.; Chou, F.-N.; Yang, D.-M. Portable FRET-Based Biosensor Device for On-Site Lead Detection. Biosensors 2022, 12, 157.


Most methods for measuring environmental lead (Pb) content are time consuming, expensive, hazardous, and restricted to specific analytical systems. To provide a facile, safe tool to detect Pb, we created pMet-lead, a portable fluorescence resonance energy transfer (FRET)-based Pb biosensor. pMet-lead comprises a 3D-printed frame housing a 405-nm laser diode — an excitation source for fluorescence emission images (YFP and CFP) — accompanied by optical filters, a customized sample holder with a Met-lead 1.44 M1 (the most recent version)-embedded biochip, and an optical lens aligned for smartphone compatibility. Measuring the emission ratios (Y/C) of the FRET component enables Pb detection with a dynamic range of nearly 2 (1.96), pMet-lead/Pb dissociation constant (Kd) 36.53 nM, and limit of detection 50 nM (1 μg/dL, 10 ppb). To mitigate earlier problems with lack of selectivity for Pb vs. zinc, we preincubated samples with tricine, a low-affinity zinc chelator. We validated pMet-lead measurements of characterized laboratory samples and unknown samples from six regions in Taiwan by inductively coupled plasma mass spectrometry (ICP-MS). Notably, two unknowns had Y/C ratios significantly higher than that of the control (3.48 ± 0.08 and 3.74 ± 0.12 vs. 2.79 ± 0.02), along with Pb concentrations (10.6 ppb and 15.24 ppb) above the WHO-permitted level of 10 ppb in tap water, while the rest four unknowns showing no detectable Pb upon ICP-MS. These results demonstrate that pMet-lead provides a rapid, sensitive means for on-site Pb detection in water from the environment and in living/drinking supply systems to prevent potential Pb poisoning.


lead biosensors; FRET; portable Pb sensor; smartphone-based device; Met-lead; tap water lead; groundwater lead


Chemistry and Materials Science, Analytical Chemistry

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

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.