Proteomics-on-a-chip for Biomarker discovery

In proteomics research still two-dimensional gel electrophoresis (2D-GE) is currently used for biomarker discovery. We applied free flow electrophoresis (FFE) separation technology combined with biomolecular interaction sensing using Surface Plasmon Resonance (SPR) imaging in an integrated proteomics-on-a-chip device as a proof of concept for biomarker discovery

Social Robots in Elderly Healthcare: A Burden or a Gift?

The healthcare sector is currently under enormous pressure and the COVID-19 pandemic does not improve this situation. The quality of healthcare will be negatively impacted when this pressure continues in the longer term. In 2050 it is expected that a total of 2.1 billion people will be aged 60+ years old. To overcome the increasing demand for healthcare by this age group, various studies are being conducted into various technological solutions, such as social robots. In this study, the Alpha Mini social robot was used in an experiment to research which tasks a social robot could assist with, to reduce the work pressure of healthcare professionals and to help the elderly live longer at their own homes. The experiment was carried out using interviews with healthcare professionals and informal caregivers about the demonstrated Alpha Mini. In addition to the experiment and interviews a survey was sent out to 237 healthcare organizations in the Netherlands to identify the 1) work pressure, 2) daily tasks, 3) social robot experiences, and 4) the features a social robot should have to gather requirements. The experiment failed due to work pressure at the healthcare organization. The survey resulted in 181 respondents. The results suggest that tasks such as reminders, setting alarms and physiotherapy have a great potential to help the healthcare professional in reducing their work pressure and tasks, and the elderly to be able to stay living longer at their own home

Point-of-care lithium monitoring in whole blood using a disposable, prefilled and ready-to-use capillary electrophoresis microchip

This paper describes a microfluidic capillary electrophoresis device with integrated conductivity detection. The device satisfies all major requirements for pointof-care testing, i.e., simple handling, low sample volume, fast measurements, clear readout, and inexpensive disposable cartridge usage. The system is currently being utilized and commercialized for monitoring lithium in whole blood, however, can potentially be applied to various other ions present in blood, urine or other bodily fluids. The chip contains a single inlet only and will be shipped prefilled with background electrolyte, sealed and blistered; ready for use at the patient’s place. A single droplet of blood is required to be placed inside the cartridge to perform the analysis typically within a couple of minutes

Bubble-Free Operation of a Microfluidic Free-Flow Electrophoresis Chip with Integrated Pt Electrodes

In order to ensure a stable and efficient separation in microfluidic free-flow electrophoresis (FFE) devices, various methods and chips have been presented until now. A major concern hereby is the generation of gas bubbles caused by electrolysis and the resulting disturbances in the position of the separated analyte lanes. Instable lane positions would lead to a decreased resolution in sample collection over time which certainly would be problematic when incorporating a stationary detector system. In contrast to our previous publications, in which we implemented laborious semipermeable membranes to keep bubbles outside the separation region, here we describe an electrochemical approach to suppress the electrolysis of water molecules and therefore bubble formation. This approach allowed a simpler and additionally a closed chip device with integrated platinum electrodes. With the use of this chip, the successful separation of three fluorescent compounds was demonstrated. Quinhydrone, which is a complex of hydroquinone and p-benzoquinone, was added only to the local flow streams along the electrodes, preventing mixing with the separation media and sample. The electrical current was generated via the oxidization and reduction of hydroquinone and p-benzoquinone up to a certain limit of the electrical current without gas formation. The separation stability was investigated for the chip with and without quinhydrone, and the results clearly indicated the improvement. In contrast to the device operating without quinhydrone, a 2.5-fold increase in resolution was achieved. Furthermore, separation was demonstrated within tens of milliseconds. This chemical approach with its high miniaturization possibilities offers an interesting alternative, in particular for low-current miniaturized FFE systems, in which large and open electrode reservoirs are not tolerabl

Microfluidic high-resolution free-flow isoelectric focusing

A microfluidic free-flow isoelectric focusing glass chip for separation of proteins is described. Free-flow isoelectric focusing is demonstrated with a set of fluorescent standards covering a wide range of isoelectric points from pH 3 to 10 as well as the protein HSA. With respect to an earlier developed device, an improved microfluidic FFE chip was developed. The improvements included the usage of multiple sheath flows and the introduction of preseparated ampholytes. Preseparated ampholytes are commonly used in large-scale conventional free-flow isoelectric focusing instruments but have not been used in micromachined devices yet. Furthermore, the channel depth was further decreased. These adaptations led to a higher separation resolution and peak capacity, which were not achieved with previously published free-flow isoelectric focusing chips. An almost linear pH gradient ranging from pH 2.5 to 11.5 between 1.2 and 2 mm wide was generated. Seven isoelectric focusing markers were successfully and clearly separated within a residence time of 2.5 s and an electrical field of 20 V mm-1. Experiments with pI markers proved that the device is fully capable of separating analytes with a minimum difference in isoelectric point of ∆(pI) = 0.4. Furthermore, the results indicate that even a better resolution can be achieved. The theoretical minimum difference in isoelectric point is ∆(pI) = 0.23 resulting in a peak capacity of 29 peaks within 1.8 mm. This is an 8-fold increase in peak capacity to previously published results. The focusing of pI markers led to an increase in concentration by factor 20 and higher. Further improvement in terms of resolution seems possible, for which we envisage that the influence of electroosmotic flow has to be further reduced. The performance of the microfluidic free-flow isoelectric focusing device will enable new applications, as this device might be used in clinical analysis where often low sample volumes are available and fast separation times are essential. \ud \ud \ud \ud \u

Liquid crystallography: 3D microdroplet arrangements using microfluidics

Monodisperse liquid particles (femtolitre oil droplets) are shown to self-organize into three-dimensional (3D) close-packed face-centered cubic (fcc) arrangements. Droplets were formed at a nanochannel-microchannel interface, and the formation of these arrangements occurred at certain flow-rate ratios of oil and water. The remarkably robust and stable structures formed in two different 'crystallographic' orientations of a face-centered cubic lattice, fcc(100) and fcc(111), as evidenced by the occurrence of square and hexagonal patterns at the plane adjacent to the channel wall. The orientation was found to depend on the oil-to-water flow-rate ratio. Similar to solid state crystals, 'crystallographic' features were observed, such as dislocation lines and defects. The 3D arrays presented in this work could provide platforms for a number of application

A prefilled, ready-to-use electrophoresis based lab-on-a-chip device for monitoring lithium in blood

We present the Medimate Multireader R, the first point-of-care lab on a chip device that is based on capillary electrophoresis. It employs disposable pre-filled microfluidic chips with closed electrode reservoirs and a single sample opening. Several technological innovations allow operation with closed reservoirs, which is essential for reliable point-of-care operation. The chips are inserted into a hand-held analyzer. In the present application, the device is used to measure the lithium concentration in blood. Lithium is quantified by conductivity detection after separation from other blood ions. Measurements in patients show good accuracy and precision, and there is no difference between the results obtained by skilled and non-skilled operators. This point-of-care device shows great promise as a platform for the determination of ionic substances in diagnostics or environmental analysi

A versatile electrophoresis-based self-test platform

This paper reports on recent research creating a family of electrophoresis-based point of care devices for the determination of a wide range of ionic analytes in various sample matrices. These devices are based on a first version for the point-of-care measurement of Li+, reported in 2010 by Floris etal. (Lab Chip 2010, 10, 1799-1806). With respect to this device, significant improvements in accuracy, precision, detection limit, and reliability have been obtained especially by the use of multiple injections of one sample on a single chip and integrated data analysis. Internal and external validation by clinical laboratories for the determination of analytes in real patients by a self-test is reported. For Li+ in blood better precision than the standard clinical determination for Li+ was achieved. For Na+ in human urine the method was found to be within the clinical acceptability limits. In a veterinary application, Ca2+ and Mg2+ were determined in bovine blood by means of the same chip, but using a different platform. Finally, promising preliminary results are reported with the Medimate platform for the determination of creatinine in whole blood and quantification of both cations and anions through replicate measurements on the same sample with the same chip

Point-of-care lithium monitoring in whole blood using a disposable, prefilled and ready-to-use capillary electrophoresis microchip

This paper describes a microfluidic capillary electrophoresis device with integrated conductivity detection. The device satisfies all major requirements for pointof- care testing, i.e., simple handling, low sample volume, fast measurements, clear readout, and inexpensive disposable cartridge usage. The system is currently being utilized and commercialized for monitoring lithium in whole blood, however, can potentially be applied to various other ions present in blood, urine or other bodily fluids. The chip contains a single inlet only and will be shipped prefilled with background electrolyte, sealed and blistered; ready for use at the patient’s place. A single droplet of blood is required to be placed inside the cartridge to perform the analysis typically within a couple of minutes