We present a methodology for building biologically inspired, soft microelectromechanical systems (MEMS) devices.

Industrial processing and heat treatment of fish muscle generally lead to losses of water-soluble components, some of which may have beneficial health effects. The aim of this work was to determine the retention of taurine, selenium and n-3 polyunsaturated fatty acids when preparing African catfish by three traditional household techniques: boiling in pouches, deep-frying and baking. Cooking did not significantly reduce the content of selenium, having retention between 91and 104%. Deepfrying resulted in a taurine loss of 40%, which was significantly higher than in baking where losses were 25% The fatty acid profiles were similar for baked and boiled fillets, but were significantly different from deep-fried fillets, due to absorption of vegetable frying oil. Baking was the best preparation technique with regard to retention of 20:5n-3 (eicosapentaenoic acid; EPA) and 22:6n-3 (docosahexaenoic acid, DHA), retaining above 80% for both fatty acids, whereas boiling and deep-frying were able to retain only approximately 54 and 65% of each, respectively.

Herein, a methodology for the directed self‐assembly of untethered microactuators and soft robotic microdevices from nanoscale building blocks is presented. The building block is a multifunctional stimuli‐responsive nanoactuator that consists of a magnetized gold nanorod encapsulated by a thermoresponsive hydrogel. The metallic core serves as a photonic nanoheater that transduces thermal energy from near‐infrared (NIR) light and a magnetic nanomotor that generates motion while driven by magnetic fields. Rapid control of temperature enables collective manipulation of nanoactuators through thermocapillary flows. In addition, catalytic activity of the nanorod instantiates a chemical reaction that covalently binds amine groups displayed on the surface of the surrounding soft gel capsule. A combination of optical and magnetic excitation realizes both reversible and permanent in situ assembly of microactuators within seconds that can perform both spatiotemporally controlled muscle‐like contraction (up to 30% strain) and motion. It is demonstrated that by linking nanoactuators with rationally designed compliant microstructures, more complex devices such as micromanipulators can be both fabricated and operated remotely. Colloidal assembly of microactuators ensures homogenous distribution of materials and functionality, thus preserving high performance provided by nanotechnology at multiple scales.

This paper presents the design, fabrication, and operation of a soft robotic compression device that is remotely powered by laser illumination. We combined the rapid and wireless response of hybrid nanomaterials with state-of-the-art microengineering techniques to develop machinery that can apply physiologically relevant mechanical loading. The passive hydrogel structures that constitute the compliant skeleton of the machines were fabricated using single-step in situ polymerization process and directly incorporated around the actuators without further assembly steps. Experimentally validated computational models guided the design of the compression mechanism. We incorporated a cantilever beam to the prototype for life-time monitoring of mechanical properties of cell clusters on optical microscopes. The mechanical and biochemical compatibility of the chosen materials with living cells together with the on-site manufacturing process enable seamless interfacing of soft robotic devices with biological specimen.