Timing readout in paper device for quantitative point-of-use hemin/G-quadruplex DNAzyme-based bioassays

• Published in: Biosensors & bioelectronics 2015-11, Vol.73, p.13-18
• Main Authors: Zhang, Yun, Fan, Jinlong, Nie, Jinfang, Le, Shangwang, Zhu, Wenyuan, Gao, Dong, Yang, Jiani, Zhang, Songbai, Li, Jianping
• Format: Article
• Language: English
• Subjects: Biological Assay - methods; Biosensing Techniques - methods; DNA Probes; DNA, Catalytic - chemistry; DNA, Catalytic - genetics; DNA, Catalytic - metabolism; DNAzyme; G-Quadruplexes; Hemin; Humans; Limit of Detection; Microfluidic paper-based analytical device; Point-of-Care Systems; Point-of-use assay; Potassium - analysis; Potassium ion; Reproducibility of Results; Timing detection
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.04.081

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. •This is the first quantitative point-of-use hemin/G-quadruplex DNAzyme assay.•This method integrates a timing detection motif with paper-based devices.•Its utility is demonstrated using a timer to enable detection of K+ in human serum.•It offers new opportunities to develop DNAzyme assays for point-of-use applications.