Highly Flexible and Transparent Polyionic‐Skin Triboelectric Nanogenerator for Biomechanical Motion Harvesting

The advances of flexible electronics have raised demand for power sources with adaptability, flexibility, and multifunctionalities. Triboelectric nanogenerators are promising replacements for traditional batteries. Here, a highly soft skin‐like, transparent, and easily adaptable biomechanical energy harvester, based on a hybrid elastomer and with a polyionic hydrogel as the electrification layer and current collector, is developed. By harvesting the energy in human motion, the device generates an open‐circuit voltage of 70 V, a short‐circuit current density of 30.2 mA m^?2, and a maximum power density of 2.79 W m^?2 in a single‐electrode working mode. Further, it is demonstrated that the device can deliver power under bending, curling or by simple tapping when attached to human skin. In addition, the optimal counterpart of the polyionic layer with highest electronegativity difference is selected from a series of contact electrification materials based on a two‐electrode working mode, where a flexible device with the matching counterparts is investigated. Serving as ionic conductor and electrification layer, this polyionic material shows promising application in future development of self‐powered flexible electronics.     

Semimicrotitration device for cholinesterase assay

A semimicrotitration device for reaction volumes of 0.5 to 2 ml and effective stirring of reaction solution or suspension is described. The principal part of the device is a combined glass electrode functioning as a reaction vessel (combined "cup"-glass electrode). Characteristics of the device are small volumes and great reliability. Nonspecific cholinesterase activities measured in rat plasma and liver tissue homogenates and compared with the activities of the same tissue and plasma samples measured radiometrically and spectrophotometrically illustrate the applicability of the device. The method is best suited for kinetic studies with multiple substrates of esterases, either in the soluble form or in tissue homogenates.     

Electrochemical microdevice with separable electrode and antibody chips for simultaneous detection of pepsinogens 1 and 2

An electrochemical microdevice with separable electrode and antibody chips has been developed and applied to detect atrophic gastritis-related proteins, pepsinogen 1 (PG1) and pepsinogen 2 (PG2), based on sandwich-type enzyme-linked immunosorbent assays (ELISAs) with horseradish peroxidase (HRP)-labeled antibody. To fabricate the electrochemical device for simultaneous analysis of several proteins, the electrode chip with eight electrode elements was assembled along with an antibody chip with eight cavities containing immobilized anti-PG1 or anti-PG2. The immunoreactions occurring in the cavities of the device were detected simultaneously by amperometry. The labeled HRP in the cavity in the presence of hydrogen peroxide catalyzed the oxidation of ferrocenemethanol (FMA) to FMA+, which was detected electrochemically by the electrode chip. The amperometric responses of respective cavities in the device increased with increasing concentration of PG1 or PG2 of 0-50 ng/ml, ensuring the simultaneous detection of PG1 and PG2. The detection limits for both PG1 and PG2 were 0.6 ng/ml (S/N=2). The electrode chip was recovered easily by disassembling the electrochemical device; thereby, it was used repeatedly, whereas the antibody chip was discarded. No marked decrease in electrochemical responses was detected after repeated use. Reuse of the electrode chip is beneficial to reduce costs of protein analysis.     

对吸附式电极记录装置的技术改进

本文介绍一种用吸附式电极记录合体细胞组织生物电位的改进装置。它的特点是在建造负压的注射器和吸附式电极之间设置一分离的小室。这一小室既保障了放大器与实验标本之间的电路连系,又可直接放置在实验标本附近,负压由改进的注射器经过充有空气的塑料管抽吸,注射器可以放在任何方便的位置上。该方法在记录小动物,如蜗牛、青蛙、等的心脏、消化道等组织器官的生物电位时都能获得比较理想的效果,对研究小动物合体细胞组织的正常机能及药物作用等都具有较好的适用价值,并具有定位准确、操作方便的优点。     

Approaches to reduce the retroaction of long-term monitoring of bioelectric events in ergonomic field studies (author's transl)

When monitoring bioelectric signals the surface electrodes can cause a retroaction on the subject thereby introducing an error of measurement. There are two types of retroaction: physical and psycho-physiological. A physical retroaction due to the hydration process of the skin occurs if 'wet' electrodes are used for the recording of the skin conductance level (SCL) causing a continuous drift of the SCL and a decrease in sensitivity to SCL changes. Therefore a dry electrode was developed with improved performance: It exhibits less sensitivity to motion, is not subject to polarization, and features better SCL long-term stability. When recording the electrocardiogram or the electromyogram a psychophysiological retroaction occurs due to the annoyance caused by the skin-irritating abrading techniques in order to decrease the skin impedance and reduce the motion artifact. In an attempt to abandon the skin preparation whenever permissible without sacrificing the measurement accuracy a performance estimation procedure was developed. Basing on the information on the signal frequency content, the electrode contact area, the required accuracy of measurement and the amplifier input impedance a decision on the necessity of skin preparation is made. Moreover, the results of a study are reported investigating the reduction of motion artifacts by means of electrode design and appropriate electrode jelly formulation.     

A tool to facilitate implantation of electrodes for electromyographic telemetry experiments

Conventional techniques for implanting electrodes into axial swimming musculature of fish are reviewed. A new device is described that reduces time for electrode implantation, ensures constancy in electrode orientation, implantation depth, and separation distance. This device is inexpensive, simple to build, and easy to use.     

A Microflow Respirometer for Measuring the Oxygen Consumption of Small Aquatic Organisms

A microrespiration device is decribed which uses a Clark electrode to measure the oxygen consumption or production of small and microscopic aquatic organisms in an open flow system. The construction and working principles of the device, which can measure oxygen consumptions as low as 0.5 nl · h⁻¹, are described. The design of the apparatus permits parallel measurements under identical conditions with a single electrode. The device can be matched to various sizes of animal and oxygen consumption rates by means of specimen chambers of different volumes (6 μl, 35 μl, 140 μl) and a variable water flow rate. The microflow respiration device has been used successfully to measure the respiration of zooplankton and meiobenthos organisms as well as protozoans and has also been used successfully on board a research vessel.     

An integrated dielectrophoretic quartz crystal microbalance (DEP-QCM) device for rapid biosensing applications

A factor limiting the detection time of biological particles using a quartz crystal microbalance (QCM) system is the kinetics of the particles arriving within the sensing region of the crystal surface. A device has been developed which, for the first time, combines ac electro-kinetic particle manipulation with simultaneous acoustic sensing on an electrode surface. We have termed this device a dielectrophoretic quartz crystal microbalance (DEP-QCM). Particles within the system are rapidly driven by electro-hydrodynamic and dielectrophoretic forces on to the crystal surface. Frequency shift analysis of mass-loaded DEP-QCM, induced by fluid motion, has shown significant improvements in rates of detection based on particle concentration, with steady-state responses established by a factor of five times faster than other quartz crystal microbalance surface loading techniques described in the literature. Comparisons of the static fluid case for QCM devices revealed that particles with a concentration of less than 10(8) nano-spheres/ml could not be detected within a 1h time period when allowed to sediment.     

Automatic termination of radiofrequency energy upon catheter dislocation.

Since 1987 radiofrequency (RF) catheter ablation has proven to be an effective treatment for many cardiac arrhythmias. However, catheter dislocation during RF delivery may result in an unintentional heating of healthy non-arrhythmogenic tissue. Therefore, a device was developed (15 cm x 9 cm x 3 cm) consisting of a microprocessor, powered by a 9 V battery and to be connected between the indifferent cable of the RF generator and the patient's back electrode that continuously reads the electrode position information using a 3 dimensional electrode visualization system (LocaLisa). A red light indicates a sudden change in electrode position and an electronic switch is activated by the software to interrupt the connection between the indifferent electrode and the RF generator resulting in a high impedance shutdown and termination of RF energy delivery. Four different sensitivity settings (10 is most and 100 is least sensitive) can be selected and were tested in an in vitro tank setup during electrode dragging speeds of 0.5 to 20 cm/sec. For the sensitivity levels 10, 20, 50 and 100, an immediate termination of RF (Atakr II, Medtronic, 25 W) was demonstrated for an electrode dragging speed of greater or equal than 1, 2, 5 and 10 cm/sec, respectively. We conclude that the developed device may improve safety during ablation procedures of cardiac arrhythmias.     

A new method to gently place biopsy needles or treatment electrodes into tissues with high target precision

We present a new core needle biopsy and treatment electrode precision placement technique which, regardless of needle size, target lesion hardness and elasticity, makes it possible to precisely place an image guided device inside the abnormal tissue. Once inside the abnormal lesion, multiple tissue samples can be collected using a dedicated trocar and collecting system. Our unique “Fourier” driver substitutes the commonly used spring-loaded device or complements the jerky insertion technique used by experienced interventional physicians. It enables the physician to precisely and with extreme tactility maneuver even large diameter core needles or treatment-electrodes into the lesion using only a diminutive external force. This is achieved by applying supporting servo-controlled mechanical high-acceleration micro-pulses, proportional to the average vector directed by the physician. The Fourier-needle or Fourier-electrode stands completely non-moving when the system automatically goes into full idling. This means that the angle of attack successively and arbitrary can be aligned to hit the target, becoming successively symmetrically inserted into even small tumors to be treated as well as exactly hit any point outlined by real time ultrasound guiding. This kind of biopsy needle or treatment electrode placement results in a uniquely accurate and less traumatic procedure. Due to the risk of disseminating viable tumor cells the precision placement device can be combined with a computer controlled anti-seeding system, denaturizing tumor cells detached during penetration of the biopsy needle or treatment electrode.     

Method for testing motion analysis laboratory measurement systems

This paper proposes a method for comparing data from accelerometers, optical based 3D motion capture systems, and force platforms (FPs) in the context of spatial and temporal differences. Testing method is based on the motion laboratory accreditation test (MLAT), which can be used to test FP and camera based motion capture components of a motion analysis laboratory. This study extends MLAT to include accelerometer data. Accelerometers were attached to a device similar to the MLAT rod. The elevation of the rod from the plane of the floor is computed and compared with the force platform vector orientation and the rod orientation obtained by optical motion capture system. Orientation of the test device is achieved by forming nonlinear equation group, which describes the components of the measured accelerations. Solution for this equation group is estimated by using the Gauss-Newton method. This expanded MLAT procedure can be used in the laboratory setting were either FP, camera based motion capture, or any other motion capture system is used along with accelerometer measurements.     

Spray Deposition of Silver Nanowire Electrodes for Semitransparent Solid‐State Dye‐Sensitized Solar Cells

Transparent top electrodes for solid‐state dye‐sensitized solar cells (ssDSCs) allow for fabrication of mechanically stacked ssDSC tandems, partially transparent ssDSCs for building integration, and ssDSCs on metal foil substrates. A solution‐processed, highly transparent, conductive electrode based on PEDOT:PSS [poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)] and spray‐deposited silver nanowires (Ag NWs) is developed as an effective top contact for ssDSCs. The electrode is solution‐deposited using conditions and solvents that do not damage or dissolve the underlying ssDSC and achieves high performance: a peak transmittance of nearly 93% at a sheet resistance of 18 Ω/square – all without any annealing that would harm the ssDSC. The role of the PEDOT:PSS in the electrode is twofold: it ensures ohmic contact between the ssDSC 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)9,9′‐spirobifluorene (Spiro‐OMeTAD) overlayer and the silver nanowires and it decreases the series resistance of the device. Semitransparent ssDSCs with D35 dye fabricated using this Ag NW/PEDOT:PSS transparent electrode show power conversion efficiencies of 3.6%, nearly as high as a reference device using an evaporated silver electrode (3.7%). In addition, the semitransparent ssDSC shows high transmission between 700–1100 nm, a necessity for use in efficient tandem devices. Such an electrode, in combination with efficient ssDSCs or hybrid perovskite‐sensitized solar cells, can allow for the fabrication of efficient, cost‐effective tandem photovoltaics.     

Highly sensitive dopamine biosensors based on organic electrochemical transistors

Organic electrochemical transistors (OECTs) based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS) with different gate electrodes, including graphite, Au and Pt electrode, etc., have been used as dopamine sensor for the first time. The sensitivity of the OECT to dopamine depends on its gate electrode and operation voltage. We find that the device with a Pt gate electrode characterized at the gate voltage of 0.6 V shows the highest sensitivity. The detection limit of the device to dopamine is lower than 5 nM, which is one order of magnitude better than a conventional electrochemical measurement with the same Pt electrode. It is expected that OECT is a good candidate for low cost and highly sensitive biosensor for the detection of dopamine.     

Label-free Isolation and Enrichment of Cells Through Contactless Dielectrophoresis

Dielectrophoresis (DEP) is the phenomenon by which polarized particles in a non-uniform electric field undergo translational motion, and can be used to direct the motion of microparticles in a surface marker-independent manner. Traditionally, DEP devices include planar metallic electrodes patterned in the sample channel. This approach can be expensive and requires a specialized cleanroom environment. Recently, a contact-free approach called contactless dielectrophoresis (cDEP) has been developed. This method utilizes the classic principle of DEP while avoiding direct contact between electrodes and sample by patterning fluidic electrodes and a sample channel from a single polydimethylsiloxane (PDMS) substrate, and has application as a rapid microfluidic strategy designed to sort and enrich microparticles. Unique to this method is that the electric field is generated via fluidic electrode channels containing a highly conductive fluid, which are separated from the sample channel by a thin insulating barrier. Because metal electrodes do not directly contact the sample, electrolysis, electrode delamination, and sample contamination are avoided. Additionally, this enables an inexpensive and simple fabrication process.cDEP is thus well-suited for manipulating sensitive biological particles. The dielectrophoretic force acting upon the particles depends not only upon spatial gradients of the electric field generated by customizable design of the device geometry, but the intrinsic biophysical properties of the cell. As such, cDEP is a label-free technique that avoids depending upon surface-expressed molecular biomarkers that may be variably expressed within a population, while still allowing characterization, enrichment, and sorting of bioparticles.Here, we demonstrate the basics of fabrication and experimentation using cDEP. We explain the simple preparation of a cDEP chip using soft lithography techniques. We discuss the experimental procedure for characterizing crossover frequency of a particle or cell, the frequency at which the dielectrophoretic force is zero. Finally, we demonstrate the use of this technique for sorting a mixture of ovarian cancer cells and fluorescing microspheres (beads).     

Reduction of knee range of motion during continuous passive motion due to misaligned hip joint centre

When using continuous passive motion (CPM) devices, appropriate setting of the device and positioning of the patient are necessary to obtain maximum range of motion (ROM). In this study, the ROMs in both the knee joint and CPM device during CPM treatment were measured using a motion analysis system for three different CPM devices. Additionally, the trajectories of the angles at the knee for hip joint misalignments were evaluated using kinematic models of the three CPM devices. The results showed that discrepancies in ROM between the knee joints and the CPM device settings during CPM treatment were revealed regardless of the CPM device and that the effect of misalignment is dependent on the design of the CPM device. The present technology could be applied for the development of a better design configuration for the CPM device to reduce the discrepancy in ROM at the knee joint.     

Reduction of knee range of motion during continuous passive motion due to misaligned hip joint centre

When using continuous passive motion (CPM) devices, appropriate setting of the device and positioning of the patient are necessary to obtain maximum range of motion (ROM). In this study, the ROMs in both the knee joint and CPM device during CPM treatment were measured using a motion analysis system for three different CPM devices. Additionally, the trajectories of the angles at the knee for hip joint misalignments were evaluated using kinematic models of the three CPM devices. The results showed that discrepancies in ROM between the knee joints and the CPM device settings during CPM treatment were revealed regardless of the CPM device and that the effect of misalignment is dependent on the design of the CPM device. The present technology could be applied for the development of a better design configuration for the CPM device to reduce the discrepancy in ROM at the knee joint.     

A nerve clamp electrode design for indirect stimulation of skeletal muscle

A nerve clamp electrode was developed to indirectly stimulate skeletal muscle innervated by α motor neurons as an alternative to conventional electrodes. The stimulating electrode device consists of a spring coil-activated nerve clamp mounted inside a 1-mL syringe barrel. Supramaximal pulses were generated by a Grass stimulator and delivered to the nerve segment via the nerve clamp electrode. The salient feature of the electrode is its ability to produce muscle contractions indirectly through stimulation of the attached nerve. Indirect muscle stimulation is critical for studying the paralytic actions of presynaptic-acting toxins such as botulinum neurotoxins (BoNT), a potent inhibitor of acetylcholine (ACh) release from α motor neurons. This device enables stimulation of muscle contraction indirectly as opposed to contraction from direct muscle stimulation. The electrode is able to stimulate indirect muscle contraction when tested on ex vivo preparations from rodent phrenic nerve-hemidiaphragm muscle in similar fashion to conventional electrodes. In addition, the electrode stimulated external intercostal nerve-muscle preparations. This was confirmed after applying BoNT serotype A, a potent inhibitor of ACh release, to induce muscle paralysis. Alternative methods, including suction and bipolar loop electrodes, were unsuccessful in stimulating indirect muscle contraction. Therefore, this novel electrode is useful for physiological assessment of nerve agents and presynaptic actions of toxins that cause muscle paralysis. This electrode is useful for stimulating nerve-muscle preparations for which the length of nerve is a concern.     

Spatial manipulation of cells and organelles using single electrode dielectrophoresis

The selection, isolation, and accurate positioning of single cells in three dimensions are increasingly desirable in many areas of cell biology and tissue engineering. We describe the application of a simple and low cost dielectrophoretic device for picking out and relocating single target cells. The device consists of a single metal electrode and an AC signal generator. It does not require microfabrication technologies or sophisticated electronics. The dielectrophoretic manipulator also discriminates between live and dead cells and is capable of redistributing intracellular organelles.     

Electrode for selective recording of electromyograms from intercostal muscles

An electromyogram-recording electrode is described that makes it possible to record separately the electrical signals generated within two closely approximated muscle layers. The device consists of two bipolar wire hook electrodes embedded in opposite faces of a thin laminated plastic wafer. The middle lamina of the wafer is a sheet of metal foil that shields the electrical field on one side of the wafer from the bipolar electrode on the other side. The device was tested by inserting it from the inside of the chest wall between the internal and external intercostal muscle layers. Signals from the two muscle layers were clearly separated. Single motor unit spikes were attenuated by factors ranging from 41 to 2.4. The device can be implanted with minimal trauma to surrounding muscles and is suitable for chronic animal experiments.     

Suspended-drop electroporation for high-throughput delivery of biomolecules into cells

We present a high-throughput method that enables efficient delivery of biomolecules into cells. The device consists of an array of 96 suspended electrode pairs, where small sample volumes are top-loaded, electroporated and bottom-ejected into 96-well plates. We demonstrate the use of this suspended-drop electroporation (SDE) device to effectively introduce fluorescent dextran, small interfering RNA (siRNA) or cDNA into primary neurons, differentiated neutrophils and other cell types with conventionally low transfection rates.