Multiplex miRNA detection is a promising way to non-invasive diagnostics. In this review, we discuss the recent advances to the multiplexing of miRNA quantification.

F₁-ATPase is the smallest known rotary motor, and it rotates in an anticlockwise direction as it hydrolyses ATP^1,2,3,4,5. Single-molecule experiments^6,7,8,9 point towards three catalytic events per turn, in agreement with the molecular structure of the complex¹⁰. The physiological function of F₁ is ATP synthesis. In the ubiquitous F₀F₁ complex, this energetically uphill reaction is driven by F₀, the partner motor of F₁, which forces the backward (clockwise) rotation of F₁, leading to ATP synthesis^11,12,13. Here, we have devised an experiment combining single-molecule manipulation and microfabrication techniques to measure the yield of this mechanochemical transformation. Single F₁ molecules were enclosed in femtolitre-sized hermetic chambers and rotated in a clockwise direction using magnetic tweezers. When the magnetic field was switched off, the F₁ molecule underwent anticlockwise rotation at a speed proportional to the amount of synthesized ATP. At 10 Hz, the mechanochemical coupling efficiency was low for the α₃β₃γ subcomplex (F₁^-ɛ), but reached up to 77% after reconstitution with the ɛ-subunit (F₁^+ɛ). We provide here direct evidence that F₁ is designed to tightly couple its catalytic reactions with the mechanical rotation. Our results suggest that the ɛ-subunit has an essential function during ATP synthesis.

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Reaction networks displaying bistability provide a chemical mechanism for long-term memory storage in cells, as exemplified by many epigenetic switches. These biological systems are not only bistable but switchable, in the sense that they can be flipped from one state to the other by application of specific molecular stimuli. We have reproduced such functions through the rational assembly of dynamic reaction networks based on basic DNA biochemistry. Rather than rewiring genetic systems as synthetic biology does in vivo, our strategy consists of building simplified dynamic analogs in vitro, in an artificial, well-controlled milieu. We report successively a bistable system, a two-input switchable memory element, and a single-input push-push memory circuit. These results suggest that it is possible to build complex time-responsive molecular circuits by following a modular approach to the design of dynamic in vitro behaviors. Our approach thus provides an unmatched opportunity to study topology/function relationships within dynamic reaction networks.