Almost all pneumatic and hydraulic actuators useful for mesoscale functions rely on hard valves control. This article describes a soft, elastomeric valve that contains bistable membrane, which acts as mechanical "switch" to control air flow. A structural instability-often called "snap-through"-enables rapid transition between two stable states of the membrane. The snap-upward pressure, ΔP1 (kilopascals), membrane differs from snap-downward ΔP2 (kilopascals). values can be designed by...

Abstract Current methods of monitoring breathing require cumbersome, inconvenient, and often expensive devices; this requirement sets practical limitations on the frequency duration measurements. This article describes a paper‐based moisture sensor that uses hygroscopic character paper (i.e. ability to adsorb water reversibly from surrounding environment) measure patterns rate respiration by converting changes in humidity caused cycles inhalation exhalation electrical signals. The changing...

This paper describes the design and characterization of an open-source "universal wireless electrochemical detector" (UWED). detector interfaces with a smartphone (or tablet) using "Bluetooth Low Energy" protocol; provides (i) user interface for receiving experimental parameters from visualizing result in real time, (ii) proxy storing, processing, transmitting data protocols. approach simplifies design, decreases both size cost hardware; it also makes UWED adaptable to different types...

Soft, pneumatic actuators that buckle when interior pressure is less than exterior provide a new mechanism of actuation. Upon application negative pressure, elastic beam elements in these undergo reversible, cooperative collapse, and generate rotational motion. These are inexpensive to fabricate, lightweight, easy control, safe operate. They can be used devices manipulate objects, locomote, or interact cooperatively with humans.

Paper microfluidics and printed electronics have developed independently, are incompatible in many aspects. Monolithic integration of on paper is demonstrated. This makes it possible to print 2D 3D fluidic, electrofluidic, electrical components paper, fabricate devices using them. As a service our authors readers, this journal provides supporting information supplied by the authors. Such materials peer reviewed may be re-organized for online delivery, but not copy-edited or typeset....

This paper describes the design and fabrication of a "pop-up" electrochemical paper-based analytical device (pop-up-EPAD) to measure beta-hydroxybutyrate (BHB)—a biomarker for diabetic ketoacidosis—using commercial combination BHB/glucometer. Pop-up-EPADs are inspired by pop-up greeting cards children's books. They made from single sheet folded into three-dimensional (3D) that changes shape, fluidic electrical connectivity, simply folding unfolding structure. The reconfigurable 3D structure...

This article demonstrates a pneumatically actuated soft robot capable of navigating the inside tube. was built using buckling pneumatic actuators (vacuum-actuated muscle-inspired structures, or VAMPs). The tube climber can navigate through with turns, inclines, and varying diameters. is also able to remove obstacles (of more than 10 times its own weight) from tubes perform clearing function. It maintains climbing performance in wet conditions under water. lightweight completely thus has...

Choline is an essential micronutrient for infants' brain development and health. To ensure that infants receive the needed daily dose of choline, U.S. Food Drug Administration (FDA) has set requirements choline levels in commercialized infant formulas. Unfortunately, not all families can access well-regulated formulas, leading to potential inadequacies intake. Economic constraints or difficulties obtaining exacerbated by situations like COVID-19, prompt stretch Accurate measurement formulas...

We report on a free-standing microfluidic pipette made in poly(dimethylsiloxane) having circulating liquid tip that generates self-confining volume front of the outlet channels. The method is flexible and scalable as geometry size recirculation zone defined by pressure, channel number, geometry. capable carrying out variety complex fluid processing operations, such mixing, multiplexing, or gradient generation at selected cells cell tissue cultures. Using an uptake assay, we show it possible...

Microfluidics has emerged as a powerful laboratory toolbox for biologists, allowing manipulation and analysis of processes at cellular sub-cellular level, through utilization microfabricated features size-scales relevant to that single cell. In the majority microfluidic devices, sample processing occur within closed microchannels, imposing restrictions on preparation use. We present an optimized non-contact open-volume tool overcome these other restrictions, use hydrodynamically confined...

This article describes a class of robots-"arthrobots"-inspired, in part, by the musculoskeletal system arthropods (spiders and insects, inter alia). Arthrobots combine mechanical compliance, lightweight simple construction, inexpensive yet scalable design. An exoskeleton, constructed from thin organic polymeric tubes, provides structural support. Pneumatic joints modeled after hydrostatic spiders provide actuation inherent compliance to external forces. inflatable elastomeric tube (a...

Potentiometric sensing of ions with ion-selective electrodes (ISEs) is a powerful technique for selective and sensitive measurement in complex matrices. The application ISEs generally limited to laboratory settings, because most commercially available reference are large, delicate, expensive, not suitable point-of-use or point-of-care measurements. This work utilizes cotton thread as substrate fabrication robust miniaturized that applications. Thread-based Cl-, K+, Na+, Ca2+ were developed....

This article describes a soft pneumatic actuator that generates cyclical motion. The consists of several (three, four, or five) chambers (arranged around the circumference circle surrounding central rod) can be actuated independently using negative pressure (or partial vacuum). Sequential actuation four-chamber device reduced moves rod cyclically in an approximately square path. We characterize trajectory and force exerted by it, as we vary material used for fabrication, number chambers,...

This paper describes electrically‐activated fluidic valves that operate based on electrowetting through textiles. The are fabricated from electrically conductive, insulated, hydrophobic textiles, but the concept can be extended to other porous materials. When valve is closed, liquid cannot pass textile. Upon application of a potential (in range 100–1000 V) between textile and liquid, opens penetrates These actuate in less than 1 s, require low energy (≈27 µJ per actuation), work with variety...

This work describes the adaptive use of conventional stainless steel pins—used in unmodified form or coated with carbon paste—as working, counter and quasi-reference electrodes electrochemical devices fabricated using cotton thread embossed omniphobic R^F paper to contain electrolyte sample.

Abstract Current methods of monitoring breathing require cumbersome, inconvenient, and often expensive devices; this requirement sets practical limitations on the frequency duration measurements. This article describes a paper‐based moisture sensor that uses hygroscopic character paper (i.e. ability to adsorb water reversibly from surrounding environment) measure patterns rate respiration by converting changes in humidity caused cycles inhalation exhalation electrical signals. The changing...

Abstract This paper describes the fabrication of elastomeric three‐dimensional (3D) structures starting from two‐dimensional (2D) sheets using a combination direct‐ink printing and relaxation strain. These are fabricated in two‐step process: first, inks deposited as 2D on stretched sheet, second, after curing inks, strain sheet causes it to deform into 3D shape. To predict bending objects with this technique, simple mechanical model is developed. The strategy initially materials fabricate...

Abstract Reliable in-vitro digestion models that are able to successfully replicate the conditions found in human gastrointestinal tract key assess fate and efficiency of new formulations aimed for oral consumption. However, current either lack capability crucial dynamics or require large volumes sample/reagents, which can be scarce when working with nanomaterials under development. Here, we propose a miniaturised system, digestion-chip, based on incubation chambers integrated...

Abstract This work presents LiFT (a lithium fiber‐based test), a low‐cost electrochemical sensor that can measure in human saliva and urine with FDA‐required accuracy. Lithium is used for the treatment of bipolar disorder, has narrow therapeutic window. Close monitoring concentration biofluids adjustment drug dosage minimize devastating side effects. an inexpensive, yet accurate simple‐to‐operate frequent at‐home testing early identification toxicity. The low cost high accuracy are enabled...

Breast cancer remains a leading cause of cancer-related mortality, with disease progression and metastasis posing significant challenges for treatment. Three-dimensional (3D) models have emerged as valuable tools studying cell biology in physiologically relevant microenvironment. Studying the tumour heterogeneity metabolic adaptations at single-cell level can be crucial to identify factors driving metastatic progression. Here, we present novel approach generate single cell-derived breast...

Exposure to electric fields affects cell membranes impacting their potential and altering cellular excitability, nerve transmission, or muscle contraction. Furthermore, stimulation influences communication, migration, proliferation, differentiation, with therapeutic applications. In vitro platforms for electrical are valuable tools studying these effects advancing medical research. this study, we developed tested a novel multi-channel in stimulator designed The device aims facilitate...

We demonstrate that pulse width flow modulation (PWFM) can be used to design fast, accurate, and precise multistage dilution modules for microfluidic devices. The PWFM stage unit presented here yields 10-fold dilution, but several stages connected in series yield higher-order dilutions. have combined two a device thus capable of diluting up 100-fold, we experimentally determined set rules conveniently utilized diluters. Microfabrication with resist-based molds yielded geometrical channel...