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

• Published in: Biosensors (Basel) Vol. 12; no. 3; p. 157
• Main Authors: Lai, Wei-Qun, Chang, Yu-Fen, Chou, Fang-Ning, Yang, De-Ming
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.03.2022; MDPI
• Subjects: 3-D technology; Biochip products; Biochips; Biosensors; Cameras; Drinking water; Emission; Emission measurements; Energy transfer; Fluorescence; Fluorescence resonance energy transfer; FRET; Groundwater; Inductively coupled plasma mass spectrometry; Lead; lead biosensors; Mass spectrometry; Mass spectroscopy; Measurement methods; Met-lead; Onsite; Optical filters; Poisoning; Portable equipment; portable Pb sensor; Proteins; Sample holders; Selectivity; Semiconductor lasers; Severe acute respiratory syndrome coronavirus 2; smartphone-based device; Smartphones; Software; tap water lead; Three dimensional printing; Zinc; United States > US; China; Japan; Taiwan; tap water lead; Met-lead; groundwater lead; portable Pb sensor; lead biosensors; FRET; smartphone-based device
• ISSN: 2079-6374; 2079-6374
• DOI: 10.3390/bios12030157

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. The pMet-lead device 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 components enabled Pb detection with a dynamic range of nearly 2 (1.96), a pMet-lead/Pb dissociation constant (K ) 45.62 nM, and a limit of detection 24 nM (0.474 μg/dL, 4.74 ppb). To mitigate earlier problems with a lack of selectivity for Pb vs. zinc, we preincubated samples with tricine, a low-affinity zinc chelator. We validated the pMet-lead measurements of the characterized laboratory samples and unknown samples from six regions in Taiwan by inductively coupled plasma mass spectrometry (ICP-MS). Notably, two unknown samples 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 remaining four unknowns showed 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.