Redox Host–Guest Nanosensors Installed with DNA Gatekeepers for Immobilization‐Free and Ratiometric Electrochemical Detection of miRNA

Abstract

Electrochemical nanosensors by integrating functional nucleic acids and nanomaterials hold a great promise in the fast detection of biomarkers, yet the current systems possess limitations on the accessibility of target–probe and probe–electrode interactions and the repeatability of detection. Herein, a host–guest assembly strategy is developed to build redox nanosensors for an immobilization‐free and ratiometric electrochemical detection system. Specifically, electroactive molecule (Em) guests are loaded in porous hosts of polydopamine nanoparticles (MPDA) to act as dual‐signal redox reporters. Hybrid DNA probes of G‐quadruplex and a single‐stranded anchor DNA are installed as gatekeepers for sealing the mesopores. Thereby, miRNA triggered Em release by strand displacement reactions and the homogeneous transportation of the hosts/guests to the electrode facilitate the generation of reference signal/response signal at different potentials. Concomitantly applied NIR irradiation boosts the electron transfer from MPDA to the electrode and results in a tenfold increase in the reference signal. Finally, the sensing system through the differential pulse voltammetry method achieves a highly repeatable detection (relative standard deviation 3.8%) of miRNA with a lower detection limit (362 × 10−15 m). This attractive system paves the way for rational designs of advanced electrochemical biosensors and smart diagnosis.

System-Level Network Analysis of a Catechol Component for Redox Bioelectronics

“…As noted, an important application of catechol-based films is redox-based bioelectronics where the catechol node facilitates redox-based communication between electronics and biology (e.g., to sense and actuate biology). − Specifically, Figure a illustrates that the catechol node can exchange electrons with biological oxidants/reductants and thus can interface into enzymatic , or cellular ,, redox networks. From a network analysis perspective, these biological interactions add nodes to the three-node (mediators plus catechol) network.…”

Nanomaterials for miRNA detection: the hybridization chain reaction strategy

“…Combining G-quadruplex DNA probes and single-stranded anchor DNA could help seal the pores. 100 Furthermore, the combination of materials can provide new materials for biosensing applications. For example, a magnetic beads and duplex-specific nuclease enzyme combination showed an enhanced detection potential for miRNAs-21 with an LOD of 170 aM.…”

Interfacially responsive electron transfer and matter conversion by polydopamine‐mediated nanoplatforms for advancing disease theranostics

“…Inspired by host–guest assemblies which have been widely used in drug controlled release, our group constructed a novel redox nanosensor integrated with MPDA as redox hosts, electroactive molecule ( E m ) guests loading in porous hosts of MPDA as dual‐signal redox reporters, as well as hybrid DNA probes of G‐quadruplex and ssDNA as gatekeeper for pore sealing for the detection of miRNA (Xie et al, 2021). Taking the advantage of host–guest assemblies, the controlled release of E m guests actuated by miRNA triggered SDR could improve the accessibility of the target to the probe, achieve one‐to‐many conversion, and mediate signal transduction.…”