DNA as Sensors and Imaging Agents for Metal Ions

Abstract

Increasing interests in detecting metal ions in many chemical and biomedical fields have created demands for developing sensors and imaging agents for metal ions with high sensitivity and selectivity. This review covers recent progress in DNA-based sensors and imaging agents for metal ions. Through both combinatorial selection and rational design, a number of metal ion-dependent DNAzymes and metal ion-binding DNA structures that can selectively recognize specific metal ions have been obtained. By attaching these DNA molecules with signal reporters such as fluorophores, chromophores, electrochemical tags, and Raman tags, a number of DNA-based sensors for both diamagnetic and paramagnetic metal ions have been developed for fluorescent, colorimetric, electrochemical, and surface Raman detections. These sensors are highly sensitive (with detection limit down to 11 ppt) and selective (with selectivity up to millions-fold) toward specific metal ions. In addition, through further development to simplify the operation, such as the use of “dipstick tests”, portable fluorometers, computer-readable discs, and widely available glucose meters, these sensors have been applied for on-site and real-time environmental monitoring and point-of-care medical diagnostics. The use of these sensors for in situ cellular imaging has also been reported. The generality of the combinatorial selection to obtain DNAzymes for almost any metal ion in any oxidation state, and the ease of modification of the DNA with different signal reporters make DNA an emerging and promising class of molecules for metal ion sensing and imaging in many fields of applications.

Adsorption of Selenite and Selenate by Metal Oxides Studied with Fluorescent DNA Probes for Analytical Application

“…DNA is very useful and versatile platform for biosensor development [17][18][19][20][21][22]. DNA is attractive for their programmability, easy to modify, and amenable to in vitro selection.…”

In vitro selection of a sodium-specific DNAzyme and its application in intracellular sensing

“…Since then, many DNAzymes have been isolated via this selection process. Among them, RNA-cleaving DNAzymes are of particular interest for metal ion sensing, due to their fast reaction rate and because the cleavage, which is catalyzed by a metal ion cofactor, can easily be converted into a detectable signal (36)(37)(38). Unlike the rational design of either small-molecule or genetically encoded protein sensors, DNAzymes with desired sensitivity and specificity for a metal ion of interest can be selected from a large Significance Monovalent ions, such as Na + , play important roles in biology, yet few sensors that image intracellular Na + have been reported.…”

Biomolecules and Pure Carbon Aggregates: An Application Towards “Green Electronics”

“…Significant progress has been made in developing sensors and imaging agents for the detection of metal ions, mostly based on organic molecules, peptides, proteins, or cells [39][40][41][42][43][44][45]. Prof. Yi Li has given a significant insight to the role of DNA as sensors and imaging agents for metal Ions [46], the structure of these systems is illustrated and described in Figure 3. DNA does not appear to be a good candidate for sensing metal ions with high selectivity because the negatively charged phosphodiester backbones of DNA are known to be capable of binding cationic metal ions with poor selectivity for any particular metal ion.…”