DNAzyme-Functionalized R-Phycoerythrin as a Cost-Effective and Environment-Friendly Fluorescent Biosensor for Aqueous Pb²⁺ Detection

• Main Authors: Jikui Wu, Yunfei Lu, Ningna Ren, Min Jia, Ruinan Wang, Junling Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Sensors
• Subjects: DNAzyme; R-phycoerythrin; sensors; Pb²⁺; fluorescence resonance energy transfer
• Online Access: https://www.mdpi.com/1424-8220/19/12/2732
• ISSN: 1424-8220

The sensitive detection of Pb²⁺ is of significant importance for food safety, environmental monitoring, and human health care. To this end, a novel fluorescent biosensor, DNAzyme-functionalized R-phycoerythrin (DNAzyme-R-PE), was presented for Pb²⁺ analysis. The biosensor was prepared via the immobilization of Iowa Black^® FQ-modified DNAzyme−substrate complex onto the surface of SPDP-functionalized R-PE. The biosensor produced a minimal fluorescence signal in the absence of Pb²⁺. However, Pb²⁺ recognition can induce the cleavage of substrate, resulting in a fluorescence restoration of R-PE. The fluorescence changes were used to measure sensitively Pb²⁺ and the limit of detection was 0.16 nM with a linear range from 0.5−75 nM. Furthermore, the proposed biosensor showed excellent selectivity towards Pb²⁺ even in the presence of other metal ions interferences and was demonstrated to successfully determine Pb²⁺ in spiked lake water samples.