We demonstrate two general classes of magnetophoretic transistors, called the "trap" and the "repel-and-collect" transistors, capable of switching single magnetically labeled cells and magnetic particles between different paths in a microfluidic chamber. Compared with prior work on magnetophoretic transistors operating in a two-dimensional in-plane rotating field, the use of a tri-axial magnetic field has the fundamental advantages of preventing particle cluster formation and better syncing of single particles with the general operating clock. We use finite element methods to investigate the energy distribution on the chip surface and to predict the particle behavior at various device geometries.
View Article and Find Full Text PDFSingle-cell RNA sequencing is a high-throughput novel method that provides transcriptional profiling of individual cells within biological samples. This method typically uses microfluidics systems to uncover the complex intercellular communication networks and biological pathways buried within highly heterogeneous cell populations in tissues. One important application of this technology sits in the fields of organ and stem cell transplantation, where complications such as graft rejection and other post-transplantation life-threatening issues may occur.
View Article and Find Full Text PDFThe precise electroencephalogram (EEG) signal classification with the highest possible accuracy is a key goal in the brain-computer interface (BCI). Considering the complexity and nonstationary nature of the EEG signals, there is an urgent need for effective feature extraction and data mining techniques. Here, we introduce a novel pipeline based on Bat and genetic algorithms for feature construction and dimension reduction of EEG signals.
View Article and Find Full Text PDFLab-on-a-chip tools have played a pivotal role in advancing modern biology and medicine. A key goal in this field is to precisely transport single particles and cells to specific locations on a chip for quantitative analysis. To address this large and growing need, magnetophoretic circuits have been developed in the last decade to manipulate a large number of single bioparticles in a parallel and highly controlled manner.
View Article and Find Full Text PDFSingle-cell analysis is an emerging discipline that has shown a transformative impact in cell biology in the last decade. Progress in this field requires systems capable of accurately moving the cells and particles in a controlled manner. Here, we present a microfluidic platform equipped with C-shaped magnetic thin films to precisely transport magnetic particles in a tri-axial rotating magnetic field.
View Article and Find Full Text PDFPrecise positioning of magnetic particles and magnetized cells in lab-on-a-chip systems has attracted broad attention. Recently, drawing inspiration from electrical circuits, we have demonstrated a magnetic particle transport platform composed of patterned magnetic thin films in a microfluidic environment, which accurately moves the particles and single cells to specific spots, called capacitors. However, we have made no prior attempts to optimize the capacitor geometry.
View Article and Find Full Text PDFPrecise manipulation of microparticles have fundamental applications in the fields of lab-on-a-chip and biomedical engineering. Here, for the first time, we propose a fully operational microfluidic chip equipped with thin magnetic films composed of straight tracks and bends which precisely transports numerous single-particles in the size range of ~ 2.8-20 µm simultaneously, to certain points, synced with the general external three-axial magnetic field.
View Article and Find Full Text PDFThe use of magnetic micro- and nanoparticles in medicine and biology is expanding. One important example is the transport of magnetic microparticles and magnetized cells in lab-on-a-chip systems. The magnetic susceptibility of the particles is a key factor in determining their response to the externally applied magnetic field.
View Article and Find Full Text PDFMagnetic nanoparticles have attracted significant attention in various disciplines, including engineering and medicine. Microfluidic chips and lab-on-a-chip devices, with precise control over small volumes of fluids and tiny particles, are appropriate tools for the synthesis, manipulation, and evaluation of nanoparticles. Moreover, the controllability and automation offered by the microfluidic chips in combination with the unique capabilities of the magnetic nanoparticles and their ability to be remotely controlled and detected, have recently provided tremendous advances in biotechnology.
View Article and Find Full Text PDFPrecise manipulation of single particles is one of the main goals in the lab-on-a-chip field. Here, we present a microfluidic platform with "T" and "I" shaped magnetic tracks on the substrate to transport magnetic particles and magnetized cells in a tri-axial time-varying magnetic field. The driving magnetic field is composed of a vertical field bias and an in-plane rotating field component, with the advantage of lowering the attraction tendency and cluster formation between the particles compared to the traditional magnetophoretic circuits.
View Article and Find Full Text PDFBackground: Nanotechnology plays an important role in various engineering fields, one of which is acoustics.
Method: Here, we review the use of nanotechnology in multiple acoustic-based bioapplications, with a focus on recent patents and advances. Nanoparticles, nanorods, nanotubes, and nanofilms used in acoustic devices are discussed.
Single-cell RNA sequencing is a powerful tool to study developmental biology but does not preserve spatial information about tissue morphology and cellular interactions. Here, we combine single-cell and spatial transcriptomics with algorithms for data integration to study the development of the chicken heart from the early to late four-chambered heart stage. We create a census of the diverse cellular lineages in developing hearts, their spatial organization, and their interactions during development.
View Article and Find Full Text PDFRecent Pat Nanotechnol
November 2021
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is one of the seven known coronaviruses infecting humans; HKU1, 229E, NL63, OC43, Acute Respiratory Syndrome Coronavirus (SARS-CoV), Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and SARS-CoV-2, the last three of which can cause severe symptoms in patients. COVID-19, previously known as 2019 novel coronavirus, caused by SARS-CoV-2, was first reported in Wuhan, China, in late 2019, and quickly resulted in a major epidemic across the world. Although the origin of SARS-CoV-2 is not clear yet, genome sequencing results suggest that this is the third reported spillover of an animal coronavirus to humans, from 2002.
View Article and Find Full Text PDFAdvances in electronics and life sciences have generated interest in "lab-on-a-chip" systems utilizing complementary metal oxide semiconductor (CMOS) circuitry for low-power, portable, and cost-effective biosensing platforms. Here, we present a simple and reliable approach for coating "high-κ" metal oxide dielectric materials with "non-fouling" (protein- and cell-resistant) poly(oligo(ethylene glycol) methyl ether methacrylate (POEGMA) polymer brushes as biointerfacial coatings to improve their relevance for biosensing applications utilizing advanced electronic components. By using a surface-initiated "grafting from" strategy, POEGMA films were reliably grown on each material, as confirmed by ellipsometric measurements and X-ray photoelectron spectroscopy (XPS) analysis.
View Article and Find Full Text PDFThe ability to direct and sort individual biological and non-biological particles into spatially addressable locations is fundamentally important to the emerging field of single cell biology. Towards this goal, we demonstrate a new class of magnetophoretic transistors, which can switch single magnetically labeled cells and magnetic beads between different paths in a microfluidic chamber. Compared with prior work on magnetophoretic transistors driven by a two-dimensional in-plane rotating field, the addition of a vertical magnetic field bias provides significant advantages in preventing the formation of particle clumps and in better replicating the operating principles of circuits in general.
View Article and Find Full Text PDFWe demonstrate magnetophoretic conductor tracks that can transport single magnetized beads and magnetically labeled single cells in a 3-dimensional time-varying magnetic field. The vertical field bias, in addition to the in-plane rotating field, has the advantage of reducing the attraction between particles, which inhibits the formation of particle clusters. However, the inclusion of a vertical field requires the re-design of magnetic track geometries which can transport magnetized objects across the substrate.
View Article and Find Full Text PDFDNA sequencing is one of the crucially important tasks in the fields of genetics and cellular biology, which is benefiting from nanotechnology. DNA carries genetic information and sequencing it in a quick way helps researchers in achieving essential goals, including personalized medicine. Solid state nanopores potentially can offer more durability, in sequencing biomolecules, over the proteinbased nanopores.
View Article and Find Full Text PDFWe investigate the non-linear dynamics of superparamagnetic beads moving around the periphery of patterned magnetic disks in the presence of an in-plane rotating magnetic field. Three different dynamical regimes are observed in experiments, including (1) phase-locked motion at low driving frequencies, (2) phase-slipping motion above the first critical frequency f, and (3) phase-insulated motion above the second critical frequency f. Experiments with Janus particles were used to confirm that the beads move by sliding rather than rolling.
View Article and Find Full Text PDFThe switching thresholds of magnetophoretic transistors for sorting cells in microfluidic environments are characterized. The transistor operating conditions require short 20-30 mA pulses of electrical current. By demonstrating both attractive and repulsive transistor modes, a single transistor architecture is used to implement the full write cycle for importing and exporting single cells in specified array sites.
View Article and Find Full Text PDFCell manipulation is instrumental in most biological applications. One of the most promising methods in handling cells and other biological particles is the magnetic manipulation technique. In this technique, magnetic nanoparticles are employed to magnetize cells.
View Article and Find Full Text PDFThe ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines.
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