The ion flux dynamics across a straight nanoslot is imaged to understand the nonequilibrium phenomenon of overlimiting current density nanoporous membrane. With slow ac field, an ion-depletion front generated intermittently from one end nanochannel, and vortex instability first predicted by Rubinstein, Staude, Kedem [Desalination 69, 101 (1988).] found arrest self-similar diffusive growth. This electrokinetic evolves into stationary interfacial array that specifies current, independent...

When a direct current (DC) electric field is applied across an ion-selective nanoporous membrane or nanochannel with overlapping Debye layer, surprising microvortex instability occurs on the side of membrane/channel through which counterions enter. Despite its micro and nano length scales, this exhibits all hallmarks other classical hydrodynamic instabilities—a subharmonic cascade, wide-band fluctuation spectrum, coherent structure dominated by spatiotemporal dynamics. Moreover, resulting...

Abstract Utilization of active colloids to transport both biological and inorganic cargo has been widely examined in the context applications ranging from targeted drug delivery sample analysis. In general, carriers are customized load one specific target via a mechanism distinct that driving transport. Here we unify these tasks extend loading capabilities include on-demand selection multiple nano/micro-sized targets without need for pre-labelling or surface functionalization. An externally...

Previously, metallodielectric Janus particles have been shown to travel with their dielectric hemisphere forward under low frequency applied electric fields as a result of asymmetric induced-charge electroosmotic flow. Here, it is demonstrated that at high frequencies, well beyond the charge relaxation time double layer induced around particle, rather than velocity decaying zero, reverse direction, traveling metallic forward. It proposed such motion surface force, arising from localized...

Iontronics that are capable of mimicking the functionality biological systems within an artificial fluidic network have long been pursued for biomedical applications and ion-based intelligence systems. Here, we report on facile robust realization iontronic bipolar memristors featuring a three-layer polyelectrolyte gel structure. Significant memristive hysteresis ion currents was successfully accomplished, memory time proved geometrically scalable from 200 to 4000 s. These characteristics...

Like ion channels, nanochannels are known to exhibit curious non-Ohmic current-voltage (I-V) characteristics with an approximate piece-wise constant differential resistance. Using a nanoslot model and nonequilibrium transport theory, we attribute the nonlinear resistance overlapping double layers inside extended polarized layer of space charge outside nanochannel. The overlimiting current beyond critical voltage is shown develop when destabilized by microvortex instability at one entrance....

Abstract A class of supercolloidal particles that controllably spin about their central axis in AC electric fields is reported. The rational design these “microspinners” enables rotation a switchable manner, which gives rise to several interesting and programmable behaviors. It shown due complex shape discrete metallic patches on surfaces, microspinners convert electrical energy into active motion via the interplay four mechanisms at different field frequency ranges. These include (in order...

Current nanochannel system paradigm commonly neglects the role of interfacing microchannels and assumes that ohmic electrical response a microchannel-nanochannel is solely determined by geometric properties nanochannel. In this work, we demonstrate overall interplay between resistance various microchannel attributed resistances. Our experiments confirm recent theoretical prediction in contrast to what was previously assumed at very low concentrations on becomes increasingly important. We...

Active particles as mobile microelectrodes for selective bacteria trapping and releasing, transport, electroporation.

Previous micromotor-based biosensing studies used to functionalize the surface of micromotor with specific molecular probes for binding target analyte, thus limiting use target. In contrast, here, we introduce a novel approach using nonfunctionalized as generic cargo carrier being able perform label-free and dynamic loading, transport, release functionalized beads. Hence, such an enables one same system sensing varying targets via different commercially available beads, demonstrating...

This research presents a novel testis-on-a-chip (ToC) platform. Testicular cells are enzymatically isolated from the seminiferous tubules of sexually immature mice, seeded in methylcellulose gel and cultured microfluidic chip. The unique design sandwiches soft between stiffer agar support gels. develop into spheroids continuing to proliferate differentiate. After seven weeks culture have over 95% viability. Confocal microscopy developed reveals structure containing various stages...

This article presents the implementation of on-chip iontronic circuits via small-scale integration multiple ionic logic gates made bipolar polyelectrolyte diodes. These are analogous to solid-state electronic circuits, with ions as charge carriers instead electrons/holes. We experimentally characterize responses a single fluidic diode junction oppositely charged polyelectrolytes (i.e., anion and cation exchange membranes), similar underlying mechanism p- n-type junction. served carry out...

We study the electro-osmotic flow through a T-junction of microchannels whose dielectric walls are weakly polarizable. The present global analysis thus extends earlier studies in literature concerning local an unbounded electrolyte solution around nearly insulated wedges. velocity field is obtained via superposition irrotational part associated with equilibrium zeta potential and induced-charge originating from interaction externally applied electric charge cloud it induces owing to leakage...

Electrokinetics promises to be the microfluidic technique of choice for portable diagnostic chips and nanofluidic molecular detectors. However, despite two centuries research, our understanding ion transport electro-osmotic flow in near nanoporous membranes, whose pores are natural nanochannels, remains woefully inadequate. This short exposition reviews various ion-flux hydrodynamic anomalies speculates on their potential applications, particularly area sensing. In process, we revisit...

A peculiar and undesirable current-voltage characteristic of nanoporous membranes is that it exhibits a voltage window with near-constant limiting-current density when bulk ions near one surface the membrane are depleted. We show both theoretically experimentally this interval disappears for an isolated circular nanopore (or narrow nanoslot) because radial field focusing at pore entrance enhances depletion effect drives ejecting hydrodynamic vortex pair amplifies ion flux into nanopore. This...

We provide an experimental proof of concept for a robust, continuously rotating microstructure---consisting two metallodielectric (gold-polystyrene) Janus particles rigidly attached to each other---which is driven in uniform ac fields by asymmetric induced-charge electro-osmosis. The pairs (doublets) are stabilized on the substrate surface which parallel plane view and normal direction applied electric field. find that radius orbit angular velocity pair predominantly dependent relative...

To address and extend the finite lifetime of Mg-based micromotors due to depletion engine (Mg-core), we examine electric fields, along with previously studied magnetic create a triple-engine hybrid micromotor for driving these micromotors. Electric fields are facile energy source that is not limited in its operation time can dynamically tune mobility by simply changing frequency amplitude field. Moreover, same electrical be used cell trapping transport as well drug delivery. However,...

Here, we integrated two key technologies within a microfluidic system, an electrokinetic preconcentration of analytes by ion Concentration Polarization (CP) and local electrochemical sensors to detect the analytes, which can synergistically act significantly enhance detection signal. This synergistic combination, offering both decoupled coupled operation modes for continuous monitoring, was validated intensified fluorescent intensities CP-preconcentrated associated enhanced response using...

Microrobots engineered from self‐propelling active particles extend the reach of robotic operations to submillimeter dimensions and are becoming increasingly relevant for various tasks, such as manipulation micro/nanoscale cargo, particularly targeted drug delivery. However, achieving deep‐tissue penetration delivery remains a challenge. This work develops novel biohybrid microrobot consisting jellyfish‐stinging capsules, which act natural nanoinjectors efficient delivery, assembled onto an...

<title>Abstract</title> Iontronics combines ions as charge carriers with electronic-like operations, enabling unique information processing, chemical regulation, and enhanced bio-integrability. This paper presents a design approach for iontronic integrated circuits, inspired by electronic abstraction layer methodology. As fundamental step, we develop compact model to the bipolar diode, conceptual framework applicable other components. The model, grounded in diode’s physical properties...

We study the induced-charge electro-osmotic flow around a stationary polarizable dielectric spheroid in presence of uniform arbitrarily oriented external electric field. A Robin-type condition connecting respective potentials within solid and bulk electro-neutral solution is highlighted formulating macroscale description for limit thin double layers low potentials. The results illustrate symmetry breaking phenomena ensuing demonstrate qualitative differences associated with variations...

A nanoslot array with a uniform surface charge and height but asymmetric slot entrances is shown to exhibit strong rectification, gating type current-voltage characteristics total current higher than the sum of isolated slots at large voltage. Unlike previous reports low-voltage rectification within nanopores nanochannels nonuniform and/or height, asymmetry due space-charge polarization interslot communication only one two different entrances.

To bridge the gap between single and isolated pore systems to multipore systems, such as membranes electrodes, we studied an array of nanochannels with varying interchannel spacing that controlled degree channel communication. Instead treating them individual channels connected in parallel or assembly like a homogeneous membrane, this study resolves pore-pore interaction. We found increased isolation leads current intensification, whereas at high voltages electroconvective effects control...