The adhesive behavior of one-dimensional (1D) materials, such as nanotubes and nanowires, plays a decisive role in the effective fabrication, functionality, and reliability of novel devices that integrate 1D components, as well as in biomimetic adhesives based on 1D arrays. This review compiles and critically evaluates recent experimental techniques that aim to characterize the adhesion behavior of interfaces formed by 1D materials, including when such materials are brought into contact with a substrate or adjacent 1D materials. The conformation of 1D material to surfaces and the associated occurrence of multi-asperity contact are discussed, and the coupling of adhesion and friction during interfacial attachment and detachment is explored. The use of 1D materials as reinforcement agents in nanocomposites and the associated interfacial characterization techniques are considered. The potential for the environmental conditions that exist during sample preparation and adhesion testing to influence 1D interfacial interactions and, ultimately, to alter the adhesion behavior of a 1D material is scrutinized. Finally, a brief perspective is provided on ongoing challenges and future directions, which include the methodical investigation of the testing environment and the alteration of adhesion through surface modification.

This paper reports a method to measure the mechanical properties of a single cell using a microfluidic chip with integrated force sensing and a liquid exchange function. A single cell is manipulated and positioned between a pushing probe and a force sensor probe using optical tweezers. These two on-chip probes were designed to capture and deform the cells. The single cell is deformed by moving the pushing probe, which is driven by an external force. The liquid–liquid interface is formed between the probes by laminar flow to change the extracellular environment. The position of the interface is shifted by controlling the injection pressure. Two positive pressures and one negative pressure are adjusted to balance the diffusion and perturbation of the flow. The mechanical properties of a single Synechocystis sp. strain PCC 6803 were measured in different osmotic concentration environments in the microfluidic chip. The liquid exchange was achieved in approximately 0.3–0.7 s, and the dynamic deformation of a single cell was revealed simultaneously. Measurements of two Young’s modulus values under alterable osmotic concentrations and the dynamic response of a single cell in osmotic shock can be collected within 30 s. Dynamic deformations of wild-type (WT) and mutant Synechocystis cells were investigated to reveal the functional mechanism of mechanosensitive (MS) channels. This system provides a novel method for monitoring the real-time mechanical dynamics of a single intact cell in response to rapid external osmotic changes; thus, it opens up novel opportunities for characterizing the accurate physiological function of MS channels in cells.

Due to the unique advantages of untethered connections and a high level of safety, magnetic actuation is a commonly used technique in microrobotics for propelling microswimmers, manipulating fluidics, and navigating medical devices. However, the microrobots or actuated targets are exposed to identical and homogeneous driving magnetic fields, which makes it challenging to selectively control a single robot or a specific group among multiple targets. This paper reviews recent advances in selective and independent control for multi-microrobot or multi-joint microrobot systems driven by magnetic fields. These selective and independent control approaches decode the global magnetic field into specific configurations for the individualized actuation of multiple microrobots. The methods include applying distinct properties for each microrobot or creating heterogeneous magnetic fields at different locations. Independent control of the selected targets enables the effective cooperation of multiple microrobots to accomplish more complicated operations. In this review, we provide a unique perspective to explain how to manipulate individual microrobots to achieve a high level of group intelligence on a small scale, which could help accelerate the translational development of microrobotic technology for real-life applications.

This paper presents a three-dimensional (3D)-atomic force microscopy (AFM) method based on magnetically driven (MD)-orthogonal cantilever probes (OCPs), in which two independent scanners with three degrees of freedom are used to achieve the vector tracking of a sample surface with a controllable angle. A rotating stage is integrated into the compact AFM system, which helps to achieve 360° omnidirectional imaging. The specially designed MD-OCP includes a horizontal cantilever, a vertical cantilever, and a magnetic bead that can be used for the mechanical drive in a magnetic field. The vertical cantilever, which has a protruding tip, can detect deep grooves and undercut structures. The design, simulation, fabrication, and performance analysis of the MD-OCP are described first. Then, the amplitude compensation and home positioning for 360° rotation are introduced. A comparative experiment using an AFM step grating verifies the ability of the proposed method to characterize steep sidewalls and corner details, with a 3D topography reconstruction method being used to integrate the images. The effectiveness of the proposed 3D-AFM based on the MD-OCP is further confirmed by the 3D characterization of a micro-electromechanical system (MEMS) device with microcomb structures. Finally, this technique is applied to determine the critical dimensions (CDs) of a microarray chip. The experimental results regarding the CD parameters show that, in comparison with 2D technology, from which it is difficult to obtain sidewall information, the proposed method can obtain CD information for 3D structures with high precision and thus has excellent potential for 3D micro–nano manufacturing inspection.

Since the first cloned sheep was produced in 1996, cloning has attracted considerable attention because of its great potential in animal breeding. Somatic cell nuclear transfer (SCNT) is widely used for creating clones. However, SCNT is very complicated to manipulate and inevitably causes intracellular damage during manipulation. Typically, only less than 1% of reconstructed embryos develop into live cloned animals. This low success rate is considered to be the major limitation in the extensive application of cloning techniques. In this study, we proposed an intracellular strain evaluation-based oocyte enucleation method to reduce potential intracellular damage in SCNT. We first calculated the intracellular strain based on the intracellular velocity field and then used the intracellular strain as a criterion to improve the enucleation operation. We then developed a robotic batch SCNT system to apply this micromanipulation method to animal cloning. Experimental results showed that we increased the blastocyst rate from 10.0% to 20.8%, and we successfully produced 17 cloned piglets by robotic SCNT for the first time. The success rate of cloning was significantly increased compared to that of traditional methods (2.5% vs 0.73% on average). In addition to the cloning technique, the intracellular strain evaluation-based enucleation method is expected to be applicable to other biological operations and for establishing a universal cell manipulation protocol to reduce intracellular damage.