Stimuli‐Responsive DNA Circuits for High‐Performance Bioimaging Application

Abstract

Probing endogenous molecules in living entities is significant to help decipher biological functions and exploit novel theranostics. DNA circuits that can recognize molecular inputs of interest and transduce them into readable signal outputs in an isothermal and autonomous manner have been actively pursued as versatile toolkits for intracellular biosensing research. Tremendous efforts are being devoted to developing integrated DNA circuits with high sensitivity, while spatiotemporal selectivity is often overlooked in the construction of functional DNA circuitry systems. This requires the development of stimuli‐responsive DNA circuits that can be activated on‐demand from the initial sensing‐blunt state to the sensing‐ready state under a programmable manner, for achieving precise bioimaging with high spatiotemporal control. In this review, an overview of recent advances in the construction of stimuli‐responsive DNA circuits that respond to particular triggers, including external physical stimuli and endogenous biological cues, and their spatiotemporally controllable molecular bioimaging applications is provided. The current challenges and potential solutions of these stimuli‐responsive DNA circuits for their future developments in this emerging field are also discussed.

Integration of Isothermal Enzyme‐Free Nucleic Acid Circuits for High‐Performance Biosensing Applications

“…Recently, several biosensors have been developed based on entropy-driven circuit (EDC), [4] hybridization chain reaction (HCR), [5][6] catalytic hairpin assembly (CHA), [7] DNAzyme with RNA-cleavage activity [8][9] or horseradish peroxidase (HRP)-like catalytic activity and RNA circuits. [10][11][12] Although RNA molecules can be genetically encoded and transcribed in living systems to develop HCR/CHA-based RNA circuits for cell imaging, [13] DNA circuits are more cost-effective and robust, [14] and thus are widely employed to fluorescent, colorimetric, and electrochemical detection of analytes. [2] In this review, recent achievements of these methods are introduced in detail.…”

Multiply Guaranteed Catalytic DNA Circuit for Cancer-Cell-Selective Imaging of miRNA and Robust Evaluation of Drug Resistance

“…However, in terms of high-contrast imaging, as is always sought in bioanalysis, the sensing performance of catalytic DNA circuits is still constrained by the inadequate signal-to-background ratios, which can be attributed to the following aspects. First, in a complex biological environment, the nonspecific cross-talk (circuit leakage) between ready-to-response circuitry reactants leads to non-negligible background noise or even false-positive signals. , Especially, without target, the cross-hybridization between these fully exposed circuitry reactants could easily induce undesired signal leakage. − Second, the low-abundance analytes are not only distributed in disease cells but also are located in normal cells, indicating that DNA circuits possibly generate indistinguishable signals in response to these analytes with the complex subcellular distribution. − These undesirable signal leakage and deficient cell selectivity can degrade the accuracy of catalytic DNA circuits in live-cell imaging studies. Therefore, it is highly needed to develop the appropriate circuitry regulation strategies that can initially deactivate DNA circuits (sense-off state) and then site-specifically or cell-selectively activate them (sense-on state) for reliable and efficient target analysis, especially in EDC circuits.…”

Efficient Intracellular MicroRNA Imaging Based on the Localized and Self-Sustainable Catalytic DNA Assembly Circuit

“…The sustainable regulation of biosystems is accomplished through a series of sophisticated biochemical reaction networks. − Recently, numerous artificial circuits were successfully designed and constructed to simulate and explore the sophisticated functions of biochemical reaction networks. − In this context, DNA circuits, on account of their specific Watson–Crick base pairing principle, have been identified as a versatile and programmable module for the simulation of dynamic reaction networks. − These molecular circuits facilitate the systematic molecular information transfer and signal transduction, thus providing valuable toolkits for biosensing, − bioregulation, − and biocomputing − researches. Catalytic hairpin assembly (CHA) is a simple catalytic circuit with high amplification efficiency under isothermal condition. − Given that its target can be recycled without affecting the normal physiological process of cells, making CHA a satisfactory alternative for biomarker sensing utilization. − However, the CHA-associated multi-component probes may degrade rapidly or produce false positive signals in complex physiological environments. − In addition, as a result of the free diffusion of multi-component CHA probes, the reaction is dependent on the random collision of reactants, thus resulting in slower reaction kinetics and longer response time. − Therefore, the development of a CHA circuit with improved reaction kinetics is highly appealing to achieve the rapid regulation of artificial reaction networks.…”