Lab on a chip for detecting Clara cell protein 16 (CC16) for potential screening of the workers exposed to respirable silica aerosol.

Early detection of pulmonary responses to silica aerosol exposure, such as lung inflammation as well as early identification of silicosis initiation, is of great importance in disease prevention of workers. In this study, to early screen the health condition of the workers who are exposed to respirable silica dusts, an immunoassay lab on a chip (LOC) was designed, developed and fully characterized for analyzing Clara cell protein 16 (CC16) in serum which has been considered as one of the potential biomarkers of lung inflammation or lung damage due to the respirable silica dusts. Sandwich immunoassay of CC16 was performed on the LOC developed with a custom-designed portable analyzer using artificial serums spiked with CC16 protein first and then human serums obtained from the coal mine workers exposed to the respirable silica-containing dusts.

Retraction: A new polymer lab-on-a-chip (LOC) based on a microfluidic capillary flow assay (MCFA) for detecting unbound cortisol in saliva.

Retraction of 'A new polymer lab-on-a-chip (LOC) based on a microfluidic capillary flow assay (MCFA) for detecting unbound cortisol in saliva' by Vinitha T. U. , , 2020, , 1961-1974, DOI: https://doi.

A new polymer lab-on-a-chip (LOC) based on a microfluidic capillary flow assay (MCFA) for detecting unbound cortisol in saliva.

Unbound cortisol in saliva, which can be detected with non-invasive sampling, is now considered as one of the most effective biomarkers for the biochemical evaluation of common mental disorders. In this work, a new polymer lab-on-a-chip (LOC) based on a microfluidic capillary flow assay (MCFA) with on-chip dried reagents was newly developed and fully characterized for the detection of unbound cortisol in saliva. The new MCFA device consisted of serially connected microchannels for sample loading, dried detection antibodies, time delay for incubation time control, a spiral reaction chamber for testing, positive and negative controls, and a capillary pump for waste fluid collection.

A new microchannel capillary flow assay (MCFA) platform with lyophilized chemiluminescence reagents for a smartphone-based POCT detecting malaria.

There has been a considerable development in microfluidic based immunodiagnostics over the past few years which has greatly favored the growth of novel point-of-care-testing (POCT). However, the realization of an inexpensive, low-power POCT needs cheap and disposable microfluidic devices that can perform autonomously with minimum user intervention. This work, for the first time, reports the development of a new microchannel capillary flow assay (MCFA) platform that can perform chemiluminescence based ELISA with lyophilized chemiluminescent reagents.

Highly Sensitive Lab on a Chip (LOC) Immunoassay for Early Diagnosis of Respiratory Disease Caused by Respirable Crystalline Silica (RCS).

Respirable crystalline silica (RCS) produced in mining and construction industries can cause life-threatening diseases such as silicosis, lung cancer, and chronic obstructive pulmonary disease (COPD). These diseases could be more effectively treated and prevented if RCS-related biomarkers were identified and measured at an early stage of disease progression, which makes development of a point of care test (POCT) platform extremely desirable for early diagnosis. In this work, a new, highly sensitive lab on a chip (LOC) immunoassay has been designed, developed, and characterized for tumor necrosis factor α (TNF-α), a protein biomarker that causes lung inflammation due to RCS exposure.

Lyophilization of chemiluminescent substrate reagents for high-sensitive microchannel-based lateral flow assay (MLFA) in point-of-care (POC) diagnostic system.

Over the last few years, lateral flow assay (LFA) devices have grown to be the most common point-of-care test (POCT) platform facilitating disease diagnostics in low-resource environments. However, the lack of consistency and the limited sensitivity of these devices often lead to misdiagnosis and generates the need for an alternate approach. A chemiluminescence based microchannel-based lateral flow assay (MLFA) in a POCT platform can result in a much higher sensitivity but involves multiple additional steps of liquid reagents for the sequential execution of the signal amplification protocol.

Pathogen-specific DNA sensing with engineered zinc finger proteins immobilized on a polymer chip.

A specific double-stranded DNA sensing system is of great interest for diagnostic and other biomedical applications. Zinc finger domains, which recognize double-stranded DNA, can be engineered to form custom DNA-binding proteins for the recognition of specific DNA sequences. As a proof of concept, a sequence-enabled reassembly of a TEM-1 β-lactamase system (SEER-LAC) was previously demonstrated to develop zinc finger protein (ZFP) arrays for the detection of a double-stranded bacterial DNA sequence.

Polysilicon based flexible temperature sensor for high spatial resolution brain temperature monitoring.

In this paper, we present a flexible temperature sensor with ultra-small polysilicon thermistors for brain temperature monitoring. In vitro sensitivity, resolution, thermal hysteresis and long term stability tests were performed. Temperature coefficient of resistance (TCR) of -0.

Spiral-based microfluidic device for long-term time course imaging of Neurospora crassa with single nucleus resolution.

Real-time imaging of fluorescent reporters plays a critical role in elucidating fundamental molecular mechanisms including circadian rhythms in the model filamentous fungus, Neurospora crassa. However, monitoring N. crassa for an extended period of time with single nucleus resolution is a technically challenging task due to hyphal growth that rapidly moves beyond a region of interest during microscopy experiments.

Development and application of a microfabricated multimodal neural catheter for neuroscience.

We present a microfabricated neural catheter for real-time continuous monitoring of multiple physiological, biochemical and electrophysiological variables that are critical to the diagnosis and treatment of evolving brain injury. The first generation neural catheter was realized by polyimide-based micromachining and a spiral rolling packaging method. The mechanical design and electrical operation of the microsensors were optimized and tailored for multimodal monitoring in rat brain such that the potential thermal, chemical and electrical crosstalk among the microsensors as well as errors from micro-environmental fluctuations are minimized.

Evaluation of microelectrode materials for direct-current electrocorticography.

Objective: Direct-current electrocorticography (DC-ECoG) allows a more complete characterization of brain states and pathologies than traditional alternating-current recordings (AC-ECoG). However, reliable recording of DC signals is challenging because of electrode polarization-induced potential drift, particularly at low frequencies and for more conducting materials. Further challenges arise as electrode size decreases, since impedance is increased and the potential drift is augmented.

Single probe for real-time simultaneous monitoring of neurochemistry and direct-current electrocorticography.

We report a novel single neural probe for real-time simultaneous monitoring of multiple neurochemicals and direct-current electrocorticography (DC-ECoG). A major advance of this probe is the inclusion of two iridium oxide reference electrodes to improve sensor accuracy. The ECoG reference electrode is identical to the ECoG recording electrodes to significantly improve DC stability, while the reference for electrochemical sensors has 10-fold lower polarization rate to minimize the small current-induced drift in the reference electrode potential.

Highly accurate thermal flow microsensor for continuous and quantitative measurement of cerebral blood flow.

Cerebral blood flow (CBF) plays a critical role in the exchange of nutrients and metabolites at the capillary level and is tightly regulated to meet the metabolic demands of the brain. After major brain injuries, CBF normally decreases and supporting the injured brain with adequate CBF is a mainstay of therapy after traumatic brain injury. Quantitative and localized measurement of CBF is therefore critically important for evaluation of treatment efficacy and also for understanding of cerebral pathophysiology.

A new smart fall-down detector for senior healthcare system using inertial microsensors.

A new smart fall-down detector for senior healthcare system using inertial microsensors and Wi-Fi technology has been designed, prototyped and characterized in this work. The detector can reduce the risk of severe injury or death caused by falling down with minimum false alarm rate. The different patterns of motion are sensed by a set of inertial sensors composed of a tri-axial accelerometer and a tri-axial gyroscope.

Circadian rhythms in Neurospora crassa on a polydimethylsiloxane microfluidic device for real-time gas perturbations.

Racetubes, a conventional system employing hollow glass tubes, are typically used for monitoring circadian rhythms from the model filamentous fungus, Neurospora crassa. However, a major technical limitation in using a conventional system is that racetubes are not amenable for real-time gas perturbations. In this work, we demonstrate a simple microfluidic device combined with real-time gas perturbations for monitoring circadian rhythms in Neurospora crassa using bioluminescence assays.

An innovative sample-to-answer polymer lab-on-a-chip with on-chip reservoirs for the POCT of thyroid stimulating hormone (TSH).

A new sample-to-answer polymer lab-on-a-chip, which can perform immunoassay with minimum user intervention through on-chip reservoirs for reagents and single-channel assay system, has been designed, developed and successfully characterized as a point-of-care testing (POCT) cartridge for the detection of thyroid stimulating hormone (TSH). Test results were obtained within 30 minutes after a sample was dropped into the POCT cartridge. The analyzed results of TSH showed a linear range of up to 55 μIU mL(-1) with the limit of detection (LOD) of 1.

Superhydrophilic multilayer silica nanoparticle networks on a polymer microchannel using a spray layer-by-layer nanoassembly method.

Nanoporous and superhydrophilic multilayer silica nanoparticle networks have been developed on a hydrophobic cyclic olefin copolymer (COC) microchannel using a spray layer-by-layer (LbL) electrostatic nanoassembly method. This powerful and promising LbL method provides a simple, cost-effective, and high-throughput nanoporous silica multilayer selectively onto the hydrophobic polymer surfaces. These newly developed multilayer networks have also been successfully characterized by contact angle measurement, environmental scanning electron microscopy (ESEM), energy-dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM).

A new on-chip whole blood/plasma separator driven by asymmetric capillary forces.

A new on-chip whole blood/plasma separator driven by asymmetric capillary forces, which are produced through a microchannel with sprayed nanobead multilayers, has been designed, fabricated and fully characterized. The silica nanobead multilayers revealing as superhydrophilic surfaces have been fabricated using a spray layer-by-layer (LbL) nano-assembly method. This new on-chip blood plasma separator has been targeted for a sample-to-answer (S-to-A) microfluidic lab-on-a-chip (LOC) toward point-of-care clinical testing (POCT).

Brain-friendly amperometric enzyme biosensor based on encapsulated oxygen generating biomaterial.

A novel first-generation Clark-type biosensor platform that can eliminate the oxygen dependence has been presented. Sufficient oxygen to drive the enzymatic reaction under hypoxic conditions was produced by encapsulated oxygen generating biomaterial, calcium peroxide. The catalase immobilized in chitosan matrix was coated on top of the groove to decompose residual hydrogen peroxide to oxygen.

A micro blood sampling system for catheterized neonates and pediatrics in intensive care unit.

A new micro blood sampling system has been designed, fabricated, and characterized to reduce iatrogenic blood loss from the catheterized neonates and pediatrics in intensive care unit by providing micro-volume of blood to analytical biomedical microdevices which can do point-of-care testing for their critical care. The system can not only save enormous iatrogenic blood loss through 1 to 10 μL of blood sampling and re-infusion of 1 to 5 mL of discard blood but also reduce the infection risk through the closed structure while satisfying the key criteria of the blood sampler. The sampled blood preserved its quality without rupturing of red blood cells verified by blood potassium concentrations of 3.

A novel microfluidic microplate as the next generation assay platform for enzyme linked immunoassays (ELISA).

In this work we introduce a novel microfluidic enzyme linked immunoassays (ELISA) microplate as the next generation assay platform for unparalleled assay performances. A combination of microfluidic technology with standard SBS-configured 96-well microplate architecture, in the form of microfluidic microplate technology, allows for the improvement of ELISA workflows, conservation of samples and reagents, improved reaction kinetics, and the ability to improve the sensitivity of the assay by multiple analyte loading. This paper presents the design and characterization of the microfluidic microplate, and its application in ELISA.

Formation of lipid bilayers inside microfluidic channel array for monitoring membrane-embedded nanopores of phi29 DNA packaging nanomotor.

An efficient method to form lipid bilayers inside an array of microfluidic channels has been developed and applied to monitor the membrane-embedded phi29 DNA packaging motor with an electrochemical characterization on a lab-on-a-chip (LOC) platform. A push-pull junction capturing approach was applied to confine a small amount of the lipid solution inside a microchannel. The selective permeability between solvents and water in PDMS was utilized to extract the solvent from the lipid solution, resulting in a self-formation of the lipid bilayer in the microchannel array.

Micromachined lab-on-a-tube sensors for simultaneous brain temperature and cerebral blood flow measurements.

This work describes the development of a micromachined lab-on-a-tube device for simultaneous measurement of brain temperature and regional cerebral blood flow. The device consists of two micromachined gold resistance temperature detectors with a 4-wire configuration. One is used as a temperature sensor and the other as a flow sensor.

Optical immunosensor using carbon nanotubes coated with a photovoltaic polymer.

In this work, an on-chip optical immunosensor using an individually assembled carbon nanotube (CNT) coated with a photovoltaic polymer has been proposed, developed, characterized, and applied for the detection of cardiac biomarkers. An individual CNT was self-assembled on a nickel (Ni)-patterned electrode by magnetically attracting the residual iron catalyst at one end of the CNT. After the CNT self-assembled electrode was prepared, it was coated with a photovoltaic polymer to implement a CNT photodetector.

An on-chip whole blood/plasma separator using hetero-packed beads at the inlet of a microchannel.

A disposable rapid on-chip whole blood/plasma separator has been simply implemented by packing two different sizes of silica beads at the inlet of a microchannel for application to point-of-care (POC) clinical diagnostics. Our suggested technique can be utilized to implement an integrated microfilter for a wide range of Lab-on-a-Chip (LOC) devices.