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Only achievable with two photons' polymerization, 3D printing at the micrometer scale is essential for the fabrication of complex objects such as photonic components, deformable microstructures, or microscaffolds for biological cells. Integrating magnetic materials inside those structures has made their remote actuation with an external magnetic field possible. However, the nature of the magnetic material, its volume, and precise position in the structure are keys for the efficiency, dexterity, and compatibility with optical or biological functions. Herein, an original approach consisting in the bonding of discrete and fully magnetic microbeads to unaffected 3D‐microprinted structures is presented. Implemented in combination with the fine control of optical and mechanical properties allowed by the careful design of the 3D architecture, it is applied to the fabrication of the first remotely tunable biconvex microlens (focal length of 18 µm). Combined with the additional precise positioning and magnetic orientation of multiple microbeads, the presented technique enables the fabrication of complex actuators such as a 100 µm microtweezer that can be translated, rotated, and opened with a single variable external magnetic field. The dexterity of this untethered micromanipulator is demonstrated through a pick‐and‐place operation of 40 µm objects in a confined environment. [ABSTRACT FROM AUTHOR]

Functional layered composites of the shape memory alloys are recently recognized as promising basic active element for microsystem technology and microrobotics. Amorphous-crystalline TiNiCu alloy ribbons at around 40 μm of thickness with an interface separating the amorphous and crystalline phases into layers were produced by melt spinning technique. It is shown that a decrease in the cooling rate of the melt from 8.9·105 to 4.2·105 K/s leads to an increase in the thickness of the crystalline layer from 2 to 10 μm. The ratio of the thicknesses of the amorphous dam and crystalline dcr layers was also varied by an electrochemical polishing method. The composite ribbons have exhibited the two-way shape memory effect (TWSME) of thermal induced bending deformation without additional thermomechanical training. It was established that when the ratio dcr/dam is changed from 0.06 to 0.35, the minimum bending radius of the ribbon decreases from 37.1 to 6.3 mm, and the maximum reversible strain increases by 0.05% to 0.27%. The minimum time of the shape recovery of the composite ribbons when heated by an electric current pulse was 14 ms, and the force generated by the ribbon with a length of 3 mm in bending reached 1.2 mN. A series of the microgrippers (microtweezers) were fabricated on the basis of the composite ribbons with TWSME. Complete technological process of manipulating graphite filaments with a diameter of 5 to 25 μm using developed microgrippers was demonstrated. [ABSTRACT FROM AUTHOR]

In this study, a three-dimensional (3D) micromanipulator mounted on a glass capillary is developed for handling biological samples, such as multicellular spheroids and embryos. To fabricate the micromanipulator, we developed an additive manufacturing system based on high-resolution microstereolithography using a 405-nm blue laser. The fabrication system makes it possible to fabricate 3D microstructures on a glass capillary with 2.5 µm lateral resolution and 25 µm layer thickness. We also demonstrated the capture and release of a spheroid with the micromanipulator fabricated using our additive manufacturing system. We showed that spheroids can be easily handled by a simple operation with minimal damage using a cage-like multiple finger structure. Additive manufacturing of tailor-made micromanipulators mounted on a glass capillary will be useful in biological and tissue engineering research.

To obtain practical information on the electroelastic behavior of poly-l-lactic acid microtweezers or catheters, a previously constructed analytical technique is used to obtain the electroelastic field solution of a poly-l-lactic acid cylindrical fiber exposed to a local electric field, which is applied through an opposed pair of square-sectioned electrodes. The numerical representation of the solution reveals the detailed field quantity distributions, their importance in the design of microtweezers and catheters, the overall deformation of such devices, and the effects of the electrode dimensions on the deformation. [ABSTRACT FROM AUTHOR]

The development of micromechanical devices (MEMS and NEMS) on the basis of nanostructured shape memory alloys is reported. A Ti50Ni25Cu25 (at. %) alloy fabricated by the melt spinning technique in the form of a ribbon with a thickness around 40 μm and a width about 1.5 mm was chosen as a starting material. Technological parameters were optimized to produce the alloy in an amorphous state. The thickness of the ribbon was reduced to 5-14 μm by means of electrochemical polishing. A nanostructural state of the thin ribbons was obtained via the dynamic crystallization of the amorphous alloy by application of a single electric pulse with duration in the range of 300-900 μs. A microtweezers prototype with a composite cantilever of 0.8 μm thick and 8 μm long was developed and produced on the basis of the obtained nanostructured thin ribbons by means of the focused ion beam technique. Controlled deformation of the micromanipulator was achieved by heating using semiconductor laser radiation in a vacuum chamber of scanning ion-probe microscope. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents the successful design, modeling, fabrication, packaging, and characterization of a mechanically actuated micro-electro-mechanical-systems (MEMS) microtweezer. This complete and modular MEMS system has minimal manufacturing complexity and can be augmented to any standard micromanipulator or positioning system. The microtweezer is mechanically actuated and hence has minimal impact on the surrounding microenvironment, a key consideration for micromanipulation. The microtweezer components are fabricated utilizing standard electroplating based processes. The microtweezer is functionally attached to a tether-cable system packaged within a stainless steel luer needle, which can be mounted to a manual controller with a luer interface. The controller, which provides axial rotational movement of the microtweezer, can be attached to any positioning stage to allow 5+ degrees of movement freedom. Mechanical modeling and characterization of the system shows that precise and controlled tool actuation is achieved with tip closing forces averaging 360mN over an actuation range of 125μm. The system''s performance and ease of use can provide the means to create and enhance a multitude of experimental preparations previously not possible. [Copyright &y& Elsevier]

Applications of microelectromechanical systems (MEMS) technology are widespread in both industrial and research fields providing miniaturized smart tools. In this review, we focus on MEMS applications aiming at manipulations and characterization of biomaterials at the single molecule level. Four topics are discussed in detail to show the advantages and impact of MEMS tools for biomolecular manipulations. They include the microthermodevice for rapid temperature alternation in real-time microscopic observation, a microchannel with microelectrodes for isolating and immobilizing a DNA molecule, and microtweezers to manipulate a bundle of DNA molecules directly for analyzing its conductivity. The feasibilities of each device have been shown by conducting specific biological experiments. Therefore, the development of MEMS devices for single molecule analysis holds promise to overcome the disadvantages of the conventional technique for biological experiments and acts as a powerful strategy in molecular biology. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Finite element analysis is used to simulate electrostatic actuated, shaped comb drives operating under dc conditions (zero actuating frequency). A dynamic multiphysics model is developed using the arbitrary Lagrangian–Eulerian (ALE) formulation. Results show the coupled interaction between the electrostatic and mechanical domains of the transducer. The analysis is based on the evolution of electrostatic force versus comb finger engagement. The relationship between incremental lateral displacement and actuation voltage illustrates the potential for stepped movement for a shaped comb drive. Additionally, through numerical simulations, this project determines an optimum design for a dc-actuated comb drive, which has controllable force output and stable engaging movement. [Copyright &y& Elsevier]

In this study, a three-dimensional (3D) micromanipulator mounted on a glass capillary is developed for handling biological samples, such as multicellular spheroids and embryos. To fabricate the micromanipulator, we developed an additive manufacturing system based on high-resolution microstereolithography using a 405-nm blue laser. The fabrication system makes it possible to fabricate 3D microstructures on a glass capillary with 2.5 µm lateral resolution and 25 µm layer thickness. We also demonstrated the capture and release of a spheroid with the micromanipulator fabricated using our additive manufacturing system. We showed that spheroids can be easily handled by a simple operation with minimal damage using a cage-like multiple finger structure. Additive manufacturing of tailor-made micromanipulators mounted on a glass capillary will be useful in biological and tissue engineering research. [ABSTRACT FROM AUTHOR]