DNA-Based Molecular Machines: Controlling Mechanisms and Biosensing Applications.

The rise of DNA nanotechnology has driven the development of DNA-based molecular machines, which are capable of performing specific operations and tasks at the nanoscale. Benefitting from the programmability of DNA molecules and the predictability of DNA hybridization and strand displacement, DNA-based molecular machines can be designed with various structures and dynamic behaviors and have been implemented for wide applications in the field of biosensing due to their unique advantages. This review summarizes the reported controlling mechanisms of DNA-based molecular machines and introduces biosensing applications of DNA-based molecular machines in amplified detection, multiplex detection, real-time monitoring, spatial recognition detection, and single-molecule detection of biomarkers.

Membrane-anchored DNA nanojunctions enable closer antigen-presenting cell-T-cell contact in elevated T-cell receptor triggering.

How the engagement of a T-cell receptor to antigenic peptide-loaded major histocompatibility complex on antigen-presenting cells (APCs) initiates intracellular signalling cascades in T cells is not well understood. In particular, the dimension of the cellular contact zone is regarded as a determinant, but its influence remains controversial. This is due to the need for appropriate strategies for manipulating intermembrane spacing between the APC-T-cell interfaces without involving protein modification.

A novel ratiometric fluorescence nanoprobe for sensitive determination of uric acid based on CD@ZIF-CuNC nanocomposites.

A novel ratiometric fluorescence nanoprobe based on carbon dots (CDs) and Cu nanoclusters (CuNCs) was designed for the label-free determination of uric acid (UA). The metal-organic framework (MOF) encapsulated CuNCs (ZIF-CuNC), and nitrogen-doped CDs can self-assemble into well-defined spherical nanocomposites (CD@ZIF-CuNC) due to physical adsorption. Under the excitation wavelength of 360 nm, the CD@ZIF-CuNC nanocomposites exhibit two evident intrinsic emissions peaked at 460 nm (CDs) and 620 nm (ZIF-CuNC), respectively.

Hg-mediated stabilization of G-triplex based molecular beacon for label-free fluorescence detection of Hg, reduced glutathione, and glutathione reductase activity.

G-triplexes have been reported recently with the similar function to G-quadruplex that can combine with thioflavin T (ThT) and emit strong fluorescence but easier to be controlled and excited. In this work, we report an Hg-mediated stabilization of G-triplex based functional molecular beacon (G3TMB) sensing system for the label-free detection of Hg, reduced glutathione (GSH), and glutathione reductase (GR) activity. In the presence of Hg, the extended G-triplex sequence containing the "T" bases can form a stable hairpin structure due to the strong interactions of "T-Hg-T", resulting in the locking of G-tracts in the stem of the G3TMB effectively.