Multiplex single-cell droplet PCR with machine learning for detection of high-risk human papillomaviruses.

High-risk human papillomavirus (HPV) testing can significantly decline the incidence and mortality of cervical cancer. Microfluidic technology provides an effective method for accurate detection of high-risk HPV by utilizing multiplex single-cell droplet polymerase chain reaction (PCR). However, current strategies are limited by low-integration microfluidic chip, complex reagent system, expensive detection equipment and time-consuming droplet identification.

Portable and Battery-Powered PCR Device for DNA Amplification and Fluorescence Detection.

Polymerase chain reaction (PCR) is a technique for nucleic acid amplification, which has been widely used in molecular biology. Owing to the limitations such as large size, high power consumption, and complicated operation, PCR is only used in hospitals or research institutions. To meet the requirements of portable applications, we developed a fast, battery-powered, portable device for PCR amplification and end-point detection.

Fluorescence quantification of intracellular materials at the single-cell level by an integrated dual-well array microfluidic device.

We present an integrated microfluidic device for quantifying intracellular materials at the single-cell level. This device combines a dual-well structure and a microfluidic control system. The dual-well structure includes capture wells (20 μm in diameter) for trapping a single cell and reaction wells (200 μm in diameter) for confining reagents.

One step DNA amplification of mammalian cells in picoliter microwell arrays.

We developed a strategy for direct DNA amplification of single cells on a PEG-modified silica chip with 30 600 picoliter-sized microwells. HPV-positive cells in heterogeneous populations were successfully detected with high accuracy sensitivity as high as single copy.

A novel dual-well array chip for efficiently trapping single-cell in large isolated micro-well without complicated accessory equipment.

Conventional cell-sized well arrays have advantages of high occupancy, simple operation, and low cost for capturing single-cells. However, they have insufficient space for including reagents required for cell treatment or analysis, which restricts the wide application of cell-sized well arrays as a single-cell research tool alone. Here, we present a novel dual-well array chip, which integrates capture-wells (20 m in diameter) with reaction-wells (100 m in diameter) and describe a flow method for convenient single-cell analysis requiring neither complicated infra-structure nor high expenditure, while enabling highly efficient single cell trapping (75.

Polarization-independent directional coupler and polarization beam splitter based on asymmetric cross-slot waveguides.

The polarization dependence of a directional coupler (DC) based on asymmetric cross-slot waveguides is investigated. Due to structural birefringence, the coupling behaviors of the quasi-TE and quasi-TM modes in the DC vary with the waveguide geometry. A polarization-independent directional coupler (PIDC) and polarization beam splitter (PBS) are proposed by tailoring the ratio of the coupling length for quasi-TE and quasi-TM modes.

An open-pattern droplet-in-oil planar array for single cell analysis based on sequential inkjet printing technology.

Cellular heterogeneity represents a fundamental principle of cell biology for which a readily available single-cell research tool is urgently required. Here, we present a novel method combining cell-sized well arrays with sequential inkjet printing. Briefly, K562 cells with phosphate buffer saline buffer were captured at high efficiency (74.

Handheld Electrical Impedance Myography Probe for Assessing Carpal Tunnel Syndrome.

Electrical impedance myography (EIM) is a novel, noninvasive, and painless technique for quantitatively assessing muscle health as well as disease status and progression. The preparatory work for commercial adhesive electrodes used in previous EIM measurements is tedious, as the electrodes need to be cut, repeatedly applied, and removed. Moreover, the electrode distances need to be measured many times.

Electrical impedance myography for discriminating traumatic peripheral nerve injury in the upper extremity.

Objective: To evaluate the potential of electrical impedance myography (EIM), which is sensitive to the changes in muscle structure and physiology, in discriminating traumatic peripheral nerve injury (TPNI) in the upper extremity. To identify factors that primarily influence muscle atrophy secondary to nerve injury.

Methods: Thirty-nine patients with TPNI underwent EIM measurement and standard electromyography tests for multiple muscles in the upper extremity.

Fabrication and Characterization of Capacitive Micromachined Ultrasonic Transducers with Low-Temperature Wafer Direct Bonding.

This paper presents a fabrication method of capacitive micromachined ultrasonic transducers (CMUTs) by wafer direct bonding, which utilizes both the wet chemical and O₂plasma activation processes to decrease the bonding temperature to 400 °C. Two key surface properties, the contact angle and surface roughness, are studied in relation to the activation processes, respectively. By optimizing the surface activation parameters, a surface roughness of 0.

Picoliter Well Array Chip-Based Digital Recombinase Polymerase Amplification for Absolute Quantification of Nucleic Acids.

Absolute, precise quantification methods expand the scope of nucleic acids research and have many practical applications. Digital polymerase chain reaction (dPCR) is a powerful method for nucleic acid detection and absolute quantification. However, it requires thermal cycling and accurate temperature control, which are difficult in resource-limited conditions.

Integrated optofluidic-microfluidic twin channels: toward diverse application of lab-on-a-chip systems.

Optofluidics, which integrates microfluidics and micro-optical components, is crucial for optical sensing, fluorescence analysis, and cell detection. However, the realization of an integrated system from optofluidic manipulation and a microfluidic channel is often hampered by the lack of a universal substrate for achieving monolithic integration. In this study, we report on an integrated optofluidic-microfluidic twin channels chip fabricated by one-time exposure photolithography, in which the twin microchannels on both surfaces of the substrate were exactly aligned in the vertical direction.

A concise iterative method using the Bezier technique for baseline construction.

A novel approach, coined the Corner-Cutting method (CC, for short), is presented in this paper which affords the efficient construction of the baseline for analytical data streams. It was derived from techniques used in computer aided geometric design, a field established to produce curves and surfaces for the aviation and automobile industries. This corner-cutting technique provided a very efficient baseline calculation through an iterative process.

Microneedle Electrode Array for Electrical Impedance Myography to Characterize Neurogenic Myopathy.

Electrical impedance myography (EIM) is a noninvasive technique for neuromuscular assessment, wherein a low-intensity alternating current is applied to a muscle, and the consequent surface voltage patterns are evaluated. Commercial wet electrodes are most commonly used for EIM. However, these electrodes are not suitable for use on small muscles, as they do not effectively solve the problem of high electrode-skin contact impedance (ESCI) that negatively influences the quality of recorded biopotentials.

Droplet-in-oil array for picoliter-scale analysis based on sequential inkjet printing.

In recent years, inkjet printing, as a new method to fabricate microdroplet microarrays, has been increasingly applied in the field of biochemical diagnostics. To further improve the general applicability of the inkjet printing technology in fabricating biochemical chips, in this work, we introduce a model to describe the multiple injection procedure implemented by the inkjet printing approach, with experimental verification. The multiple injection model demonstrates a new sequential inkjet printing method that generates picoliter-scale multicomponent droplet-in-oil arrays via multistep printing on uniform planar substrates.

An impedance immunosensor based on low-cost microelectrodes and specific monoclonal antibodies for rapid detection of avian influenza virus H5N1 in chicken swabs.

Early screening of suspected cases is the key to control the spread of avian influenza (AI) H5N1. In our previous studies, an impedance biosensor with an interdigitated array microelectrode based biochip was developed and validated with pure AI H5 virus, but had limitations in cost and reliability of the biochip, specificity of the antibody against Asian in-field H5N1 virus and detection of H5N1 virus in real samples. The purpose of this study is to develop a low-cost impedance immunosensor for rapid detection of Asian in-field AI H5N1 virus in chicken swabs within 1h and validate it with the H5N1 virus.

High-speed silicon modulator with band equalization.

Electro-optic modulation up to 70 Gbit/s has been demonstrated using a silicon Mach-Zehnder modulator with a bias voltage of -1.5 V. In a wide frequency range from DC, an increasing input impedance of the modulator was designed to equalize its electro-optic frequency response.

A novel picoliter droplet array for parallel real-time polymerase chain reaction based on double-inkjet printing.

We developed and characterized a novel picoliter droplet-in-oil array generated by a double-inkjet printing method on a uniform hydrophobic silicon chip specifically designed for quantitative polymerase chain reaction (qPCR) analysis. Double-inkjet printing was proposed to efficiently address the evaporation issues of picoliter droplets during array generation on a planar substrate without the assistance of a humidifier or glycerol. The method utilizes piezoelectric inkjet printing equipment to precisely eject a reagent droplet into an oil droplet, which had first been dispensed on a hydrophobic and oleophobic substrate.

Fast and efficient silicon thermo-optic switching based on reverse breakdown of pn junction.

We propose and demonstrate a fast and efficient silicon thermo-optic switch based on reverse breakdown of the pn junction. Benefiting from the direct heating of silicon waveguide by embedding the pn junction into the waveguide center, fast switching with on/off time of 330 and 450 ns and efficient thermal tuning of 0.12  nm/mW for a 20 μm radius microring resonator are achieved, indicating a high figure of merit of only 8.

Low cross-talk 2 × 2 silicon electro-optic switch matrix with a double-gate configuration.

In this study, a low cross-talk 2 × 2 silicon electro-optic switch matrix based on a double-gate configuration is proposed and experimentally demonstrated. The switch matrix consists of four Mach-Zehnder-based 2 × 2 switching elements with 400 μm long modulation arms. Low cross-talk values of -31 and -43 dB are, respectively, obtained for the "cross" and "bar" states over a 40 nm wide wavelength range around 1550 nm.

Compact and low-loss silicon power splitter based on inverse tapers.

A compact, low-loss, optical power splitter based on inverse tapers is proposed and fabricated on a silicon-on-insulator platform. High efficiency mode evolution between the fundamental mode of the input waveguide and the super mode of the output waveguides is realized using optimized tapers. A 1×4 splitter with insertion loss lower than 0.

Improved picoliter-sized micro-reactors for high-throughput biological analysis.

High-throughput pyrosequencing, carried out in millions of picoliter-sized reactors on a fiber-optic slide, is known for its longer read length. However, both optical crosstalk (which reduces the signal-to-noise ratio of CCD images) and chemical retention adversely affect the accuracy of chemiluminescence determination, and ultimately decrease the read length and the accuracy of pyrosequencing results. In this study, both titanium and oxidized aluminum films were deposited on the side walls and upper faces of micro-reactor slides to enhance optical isolation; the films reduced the inter-well crosstalk by one order of magnitude.

Design of polarization-independent adiabatic splitters fabricated on silicon-on-insulator substrates.

A novel design for a polarization-independent SOI-based 2 × 2 3-dB adiabatic splitter with sub-micron-scale dimensions is proposed and modeled. To achieve slow and smooth mode evolution, a structure with simultaneous tapering of velocity and coupling is used. To reduce the adiabatic region length by adjusting the gap separation, the coupling strengths of TE and TM polarizations as a function of the gap value are analyzed.

Nonblocking 4×4 silicon electro-optic switch matrix with push-pull drive.

A compact rearrangeable nonblocking 4×4 silicon electro-optic switch matrix based on a Spanke-Beneš network is proposed and fabricated by a 0.18 μm standard commercial complementary metal-oxide semiconductor line. By respectively modulating the two modulation arms with a push-pull drive, a cross talk (CT) of less than -18 dB is obtained for the switching element with 150-μm-long modulation arms.

Two-mode multiplexer and demultiplexer based on adiabatic couplers.

A two-mode (de)multiplexer based on adiabatic couplers is proposed and experimentally demonstrated. The experimental results are in good agreement with the simulations. An ultralow mode cross talk below -36 dB and a low insertion loss of about 0.