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Timing readout in paper device for quantitative point-of-use hemin/G-quadruplex DNAzyme-based bioassays
- Zhang, Yun, Fan, Jinlong, Nie, Jinfang, Le, Shangwang, Zhu, Wenyuan, Gao, Dong, Yang, Jiani, Zhang, Songbai, Li, Jianping
- Biosensors & bioelectronics 2015 v.73 pp. 13-18
- bioassays, biosensors, blood serum, humans, hydrophilicity, hydrophobicity, paper, potassium, wettability
- This work describes a quantitative point-of-use hemin/G-quadruplex DNAzyme-based assay that integrates a simple timing detection motif with low-cost, portable microfluidic paper-based analytical devices (μPADs). The timing readout is based on the selective DNAzyme-mediated wettability change of paper from hydrophilicity to hydrophobicity. Its utility is well demonstrated with sensitive, specific detection of K+ ion as a model analyte in artificial samples as well as real human serum samples. This new method only requires a ubiquitous cheap timer (or a cell phone with a timing function) to provide quantitative results. It could offer new opportunities for the development of more peroxidase-mimicking DNAzyme-based bioassays that are simple, affordable, portable, and operable by minimally-trained users for broad point-of-use applications especially in resource-poor settings.