Pore structure-based analytical techniques have great potential applications for the detection of biological molecules. However, the sophistication of traditional pore sensors is restricted in their applicability of analytical chemistry due to a lack of effective carrier probes. Here, we used porous coordination network-224 (PCN-224) composite probes in conjunction with a glass nanopipette (GN) as a sensing platform. The sensor exhibits a good fluorescence signal and a change in GN’s ionic current at the same time. Due to the volume exclusion mechanism coming from PCN-224, the detection limit of target DNA reaches 10 fM in a GN with a diameter of up to ca. 260 nm, outperforming a simple probe. The structure of the composite probe is optimized by the probe’s pairing efficiency. Furthermore, the sensor can also discriminate between 1-, 3-, and 5-mismatch DNA sequences and capture the target DNA from a complex mixture. Based on the GN platform, a series of techniques for detecting biomolecules are expected to emerge because of its simplicity, robustness, and universality by incorporating advanced nanoprobes.

The combination of DNA nanotechnology and nanopore sensing technology greatly promotes the researches on the target molecules or ions detection. The large solid-state nanopores/nanochannels show better mechanical stability and reproducibility,...

Living organisms use the amplification of molecular motions over orders of magnitude to produce deformation, motion, and function on the macroscale. The design of artificial molecular machines that can mimic their biological counterparts in the production of such macroscopic actuation is of great interest. Here, we designed a polymerizable bisazobenzene-based molecular photoswitch that displays a highly directional geometrical transformation upon photoisomerization. When this photoswitch is incorporated into polymer networks as a cross-linker, its directional contraction and expansion drive the movement and rearrangement of polymer chains and amplifies these motions to the macroscale, resulting into a direct volume change and deformation of the bulk polymeric hydrogels. These photoswitchable hydrogels therefore mimic macroscopic biological motions such as muscular contraction and light-driven bending similar to phototropism. Furthermore, the use of this photoswitch to tune the macroscopic properties of hydrogels is in principle transferable to a variety of polymeric systems. This work develops a clear connection between molecular motion and macroscopic actuation, providing a platform to investigate this relationship further.

No abstract

Acoustic-structure coupling effect is an important factor that affects water-filled pipe muffler's acoustic performance. In this paper, finite element method (FEM) was used to study acoustic characteristics of water-filled pipe muffler. Circumferential chamber and perforated pipe walls of the muffler were taken as elastic plates. The effect of acoustic-structure coupling is considered when calculating transmission loss (TL) of water-filled expansion chamber muffler, water mufflers with perforated plate and perforated pipe. In this paper, the effects of the wall thickness and material of the elastic wall and the structural parameters of the perforated plate on the acoustic characteristics of the water muffler are further studied. By comparing the elastic cavity wall of the muffler with the elastic perforated pipe wall, the contribution of both to the acoustic characteristics of the perforated pipe water muffler is obtained.