One-Step RT-qPCR for Viral RNA Detection Using Digital Analysis.

The rapid detection of viruses is becoming increasingly important to prevent widespread infections. However, virus detection reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is time-consuming, as it involves independent nucleic acid extraction and complementary DNA synthesis. This process limits the potential for rapid diagnosis and mass analysis, which are necessary to curtail viral spread.

Surface Activity-Tuned Metal Oxide Chemiresistor: Toward Direct and Quantitative Halitosis Diagnosis.

Continuous monitoring of hydrogen sulfide (HS) in human breath for early stage diagnosis of halitosis is of great significance for prevention of dental diseases. However, fabrication of a highly selective and sensitive HS gas sensor material still remains a challenge, and direct analysis of real breath samples has not been properly attempted, to the best of our knowledge. To address the issue, herein, we introduce facile cofunctionalization of WO nanofibers with alkaline metal (Na) and noble metal (Pt) catalysts the simple addition of sodium chloride (NaCl) and Pt nanoparticles (NPs), followed by electrospinning process.

Wrist-wearable bioelectrical impedance analyzer with miniature electrodes for daily obesity management.

Bioelectrical impedance analysis (BIA) is used to analyze human body composition by applying a small alternating current through the body and measuring the impedance. The smaller the electrode of a BIA device, the larger the impedance measurement error due to the contact resistance between the electrode and human skin. Therefore, most commercial BIA devices utilize electrodes that are large enough (i.

Toward a disposable low-cost LOC device: heterogeneous polymer micro valve and pump fabricated by UV/ozone-assisted thermal fusion bonding.

Herein, a heterogeneous polymer micro valve and pump with a polypropylene (PP) membrane was developed in a low-cost manner UV/ozone-assisted thermal fusion bonding. The proposed fabrication technique allowed for a geometrically selective bonding; consequently, the membrane was prevented from bonding with the valve seat of the diaphragm micro-valve, without patterning a protection layer or introducing an additional structure. The developed device withstands 480 kPa of static pressure and up to 350 kPa of a vibration pressure, providing sufficient bonding strength for microfluidic actuations.

Simultaneous capture and in situ analysis of circulating tumor cells using multiple hybrid nanoparticles.

Using hybrid nanoparticles (HNPs), we demonstrate simultaneous capture, in situ protein expression analysis, and cellular phenotype identification of circulating tumor cells (CTCs). Each HNP consists of three parts: (i) antibodies that bind specifically to a known biomarker for CTCs, (ii) a quantum dot that emits fluorescence signals, and (iii) biotinylated DNA that allows capture and release of CTC-HNP complex to an in-house developed capture & recovery chip (CRC). To evaluate our approach, cells representative of different breast cancer subtypes (MCF-7: luminal; SK-BR-3: HER2; and MDA-MB-231: basal-like) were captured onto CRC and expressions of EpCAM, HER2, and EGFR were detected concurrently.

Solid phase DNA extraction with a flexible bead-packed microfluidic device to detect methicillin-resistant Staphylococcus aureus in nasal swabs.

We have developed a bead-packed microfluidic device with a built-in flexible wall to automate extraction of nucleic acids from methicillin-resistant Staphylococcus aureus (MRSA) in nasal swabs. The flexible polydimethylsiloxane (PDMS) membrane was designed to manipulate the surface-to-volume ratio (SVR) of bead-packed chambers in the range of 0.05 to 0.

Functional integration of DNA purification and concentration into a real time micro-PCR chip.

Microfluidic devices for on-chip amplification of DNA from various biological and environmental samples have gained extensive attention over the past decades with many applications including molecular diagnostics of disease, food safety and biological warfare testing. But the integration of sample preparation functions into the chip remains a major hurdle for practical application of the chip-based diagnostic system. We present a PCR-based molecular diagnostic device comprised of a microfabricated chip and a centrifugal force assisted liquid handling tube (CLHT) that is designed to carry out concentration and purification of DNA and subsequent amplification of the target gene in a single chip.

Surface acoustic wave immunosensor for real-time detection of hepatitis B surface antibodies in whole blood samples.

We demonstrate an application of Love wave mode surface acoustic wave (SAW) immunosensor to detect hepatitis B surface antibody (HBsAb) in aqueous conditions. SiO(2) guiding layer was deposited on 36 degrees YX-LiTaO(3) piezoelectric single crystal substrate to protect the electrodes and to trap the acoustic energy near the surface, and hepatitis B surface antigen (HBsAg) was immobilized on the sensing area. The resonance frequency shift was monitored to detect specific binding of HBsAb to immobilized HBsAg.

Bacterial DNA sample preparation from whole blood using surface-modified Si pillar arrays.

A novel bacterial DNA sample preparation device for molecular diagnostics has been developed. On the basis of optimized conditions for bacterial adhesion, surface-modified silicon pillar arrays for bacterial cell capture were fabricated, and their ability to capture bacterial cells was demonstrated. The capture efficiency for bacterial cells such as Escherichia coli, Staphylococcus epidermidis, and Streptococcus mutans in buffer solution was over 75% with a flow rate of 400 microL/min.

Nanopore sensor for fast label-free detection of short double-stranded DNAs.

Functionalizing surface enhanced the molecular sensing ability of a fabricated nanopore by increasing the translocation duration time for a short double-stranded DNA. The surface of nanopore was derivatized with gamma-aminopropyltriethoxysilane and the positively charged surface attracted DNA molecules when they were in the vicinity of nanopore. The translocation duration time of DNA increased due to the strong electrostatic interaction and it enabled us to detect a short double-stranded DNA (<1 kbp) that is under the size limit of a conventional solid state nanopore sensor.

Clinical evaluation of micro-scale chip-based PCR system for rapid detection of hepatitis B virus.

The polymerase chain reaction (PCR) is widely used to amplify a small amount of DNA in samples for genetic analysis. Rapid and accurate amplification is prerequisite for broad applications including molecular diagnostics of diseases, food safety, and biological warfare tests. We have developed a rapid real-time micro-scale chip-based PCR system, which consists of six individual thermal cycling modules capable of independent control of PCR protocols.

World-to-chip microfluidic interface with built-in valves for multichamber chip-based PCR assays.

We report a practical world-to-chip microfluidic interfacing method with built-in valves suitable for microscale multichamber chip-based assays. One of the primary challenges associated with the successful commercialization of fully integrated microfluidic systems has been the lack of reliable world-to-chip microfluidic interconnections. After sample loading and sealing, leakage tests were conducted at 100 degrees C for 30 min and no detectable leakage flows were found during the test for 100 microchambers.