DNAzyme sensors for detection of metal ions in the environment and imaging them in living cells

Abstract

The on-site and real-time detection of metal ions is important for environmental monitoring and for understanding the impact of metal ions on human health. However, developing sensors selective for a wide range of metal ions that can work in the complex matrices of untreated samples and cells presents significant challenges. To meet these challenges, DNAzymes, an emerging class of metal ion-dependent enzymes selective for almost any metal ion, have been functionalized with fluorophores, nanoparticles and other imaging agents and incorporated into sensors for the detection of metal ions in environmental samples and for imaging the metal ions in living cells. Herein, we highlight the recent developments of DNAzyme-based fluorescent, colorimetric, SERS, electrochemical and electrochemiluminscent sensors for metal ions for these applications.

Biocomputing for Portable, Resettable, and Quantitative Point‐of‐Care Diagnostics: Making the Glucose Meter a Logic‐Gate Responsive Device for Measuring Many Clinically Relevant Targets

“…In summary,w ehave demonstrated an ew biocomputing platform that integrates PGMs with logic capability using metal-specific DNAzymes and protein enzymes as building blocks.Acomplete set of seven binary logic gates (YES,NOT, OR, NOR, NAND,I NHIBIT,a nd Concatenated) were constructed on PGMs for the detection of multiple biological substances.Aseries of metal ions,d isease-related metabolites,coenzymes,and native enzymes have been employed as inputs,u sing glucose and/or NADH signal on aP GM as outputs.P otential applications of these methods for POC diagnostics of diseases (for example,h yponatremia and hypernatremia) have also been demonstrated. Additionally, our PGM-based platform offers unique advantages compared to existing methods for biocomputing applications:1)itdoes not require calibration for every measurement once the calibration curves are obtained for the non-glucose targets,as the glucose readout by PGMs has been demonstrated to have minimal interference from the human sample matrix; [19] 2) this platform architecture is modular and could be repurposed for various applications.F or instance,t he DNAzyme sequences can be interchanged to enable responsiveness to other input monovalent (for example,A g + ), [20] divalent (for example,P b 2+ ), [21] and trivalent metal ions (for example, Cr 3+ ), [22] while the modulation of native-enzyme-based logic systems can be achieved by switching to other biologically/ clinically relevant targets involved in the cascade enzymatic reactions (for example,l actate/pyruvate and G6PD). [9c] We anticipate that such PGM-based logic biosensors,w hich are capable of in vitro computation, can be tailored according to medical knowledge and used as expert biosensing devices for POC diagnostics.…”

An Ultrasensitive Non-Enzymatic Sensor for Quantitation of Anti-Cancer Substance Chicoric Acid Based on Bimetallic Nanoalloy with Polyetherimide-Capped Reduced Graphene Oxide

“…Additionally, sensors based on ternary nanocomposites have been used to detect caffeic acid rapidly and accurately [23]. Importantly, electrochemical sensors have high biocompatibility, which enables them to study the target substances in living cells [24][25][26]. In this regard, electrochemical sensors have the potential to facilitate research into pharmacodynamic effects of chicoric acid at the cellular level.…”

Towards Nanomaterials for Cancer Theranostics: A System of DNA-Modified Magnetic Nanoparticles for Detection and Suppression of RNA Marker in Cancer Cells

“…In this study we explore another approach for the design of cancer theranostic material based on magnetic nanoparticles conjugated with a deoxyribozyme (DZ) probe complementary to a known mRNA biomarker for metastatic breast adenocarcinoma. Deoxyribozymes [5][6][7] are catalytic DNA molecules that are widely used in the areas of biocomputational logic gates and circuits (DNA computing) [8,9], programmable materials [10], ultrasensitive analytical methods [11,12], and for therapeutic applications [13][14][15].…”