Rapid heavy metal sensing platform: A case of triple signal amplification strategy for the sensitive detection of serum copper

A ratiometric fluorescence sensor for 5-hydroxymethylfurfural detection based on strand displacement reaction

A ratiometric fluorescence sensor for 5-hydroxymethylfurfural detection based on strand displacement reaction.

A DNAzyme-based normalized fluorescence strategy for direct quantification of endogenous zinc in living cells

For many years, numerous efforts have been focused on the development of sensitive, selective, and practical sensors for environmental monitoring, food safety, and medical diagnostic applications. However, the transition from innovative research to commercial success is relatively sparse. In this review, we identify several barriers to developing successful sensors for practical applications, including the lack of general methods to (a) generate receptors for a wide range of targets, (b) improve sensor selectivity to overcome interferences, (c) transduce the selective binding to different optical, electrochemical, and other signals, and (d) tune dynamic range to match thresholds of detection required for different targets. We then summarize solutions to overcome these barriers using sensors based on functional nucleic acids that include DNAzymes, aptamers, and aptazymes and how these sensors are coupled to widely available measurement devices to expand their capabilities and lower the barrier for their practical applications in the field and point-of-care settings. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 15 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Overcoming Major Barriers to Developing Successful Sensors for Practical Applications Using Functional Nucleic Acids.

DNAzymes have emerged as a powerful class of sensors for metal ions due to their high selectivity over a wide range of metal ions, allowing for on-site and real-time detection. Despite much progress made in this area, detecting and quantifying tightly bound metal ions, such as those in the blood serum, remain a challenge because the DNAzyme sensors reported so far can detect only mobile metal ions that are accessible to bind the DNAzymes. To overcome this major limitation, we report the use of a photocaged chelator, XDPAdeCage to extract the Zn2+ from the blood serum and then release the chelated Zn2+ into a buffer using 365 nm light for quantification by an 8-17 DNAzyme sensor. Protocols to chelate, uncage, extract, and detect metal ions in the serum have been developed and optimized. Because DNAzyme sensors for other metal ions have already been reported and more DNAzyme sensors can be obtained using in vitro selection, the method reported in this work will significantly expand the applications of the DNAzyme sensors from sensing metal ions that are not only free but also bound to other biomolecules in biological and environmental samples.

Liangyuan Cai

Papers

Detection and Quantification of Tightly Bound Zn2+ in Blood Serum Using a Photocaged Chelator and a DNAzyme Fluorescent Sensor.