Many modern electronic applications rely on functional units arranged in an active‐matrix integrated on a single chip. The active‐matrix allows numerous identical device pixels to be addressed within a single system. However, next‐generation electronics requires heterogeneous integration of dissimilar devices, where sensors, actuators, and display pixels sense and interact with the local environment. Heterogeneous material integration allows the reduction of size, increase of functionality, and enhancement of performance; however, it is challenging since front‐end fabrication technologies in microelectronics put extremely high demands on materials, fabrication protocols, and processing environments. To overcome the obstacle in heterogeneous material integration, digital electrochemistry is explored here, which site‐selectively carries out electrochemical processes to deposit and address electroactive materials within the pixel array. More specifically, an amorphous indium‐gallium‐zinc oxide (a‐IGZO) thin‐film‐transistor (TFT) active‐matrix is used to address pixels within the matrix and locally control electrochemical reactions for material growth and actuation. The digital electrochemistry procedure is studied in‐depth by using polypyrrole (PPy) as a model material. Active‐matrix‐driven multicolored electrochromic patterns and actuator arrays are fabricated to demonstrate the capabilities of this approach for material integration. The approach can be extended to a broad range of materials and structures, opening up a new path for advanced heterogeneous microsystem integration.

Flexible electronics has gained tremendous attention over the past decades, revolutionizing fields such as telecommunication, multimedia, and healthcare. [1] Major electronic components, e.g., interconnects, antennas, diodes, and transistors, have been fabricated on thin polymeric foils to generate new options in the toolkit of developers. Applying thin polymeric foils as substrates facilitates the production of electronic systems with low weight, shape compliance, robustness, and reliability with ever-increasing complexity. The ultrathin design of these electronic devices has promoted bioelectronics that include artificial skins, [2] sensor arrays, [3] electronic implants such as brain probes, [4] and nerve cuffs, [5] to name a few. The ability to naturally conform to complex 3D shaped anatomies is a vital feature for electronic devices to interact with soft biological tissue. And while the shape of a large-area flexible electronic device can be easily adapted manually to the geometric requirements of the final application, handling becomes increasingly more challenging when aiming at smaller dimensions, when, e.g., a submillimeter nerve fiber bundle has to be enclosed gently with a similarly small cuff implant. [6] Shapeable microelectronic devices, which transform their shape on demand, provide an alternative strategy to accomplish this challenging task. [7] For instance, soft microscale structures with integrated electronic circuits have recently been demonstrated to wrap around peripheral nerves in situ when exposed to elevated temperatures or moisture. [8,9] These devices, however, lack the ability to reshape repeatedly and on demand in the operating environment. Such functionalities require the integration of biocompatible flexible shape and position sensors together with robust microactuators, fabricated ideally by a monolithic wafer-scale process.Among a variety of small-scale actuators that are driven by pneumatic [10,11] and hydraulic [12] pressure, electric [13] and

Self assembled catheters with deep sub-mm diameters deliver liquids, carry out micromanipulation, and sense magnetic fields.

Oscillations at several hertz are a key feature of dynamic behavior of various biological entities, such as the pulsating heart, firing neurons, or the sperm-beating flagellum. Inspired by nature's fundamental self-oscillations, we use electroactive polymer microactuators and three-dimensional microswitches to create a synthetic electromechanical parametric relaxation oscillator (EMPRO) that relies on the shape change of micropatterned polypyrrole and generates a rhythmic motion at biologically relevant stroke frequencies of up to ~95 Hz. We incorporate an Ag-Mg electrochemical battery into the EMPRO for autonomous operation in a nontoxic environment. Such a self-sufficient self-oscillating microsystem offers new opportunities for artificial life at low Reynolds numbers by, for instance, mimicking and replacing nature's propulsion and pumping units.

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