Sample-to-answer sensing technologies for nucleic acid preparation and detection in the field.

Efficient sample preparation and accurate disease diagnosis under field conditions are of great importance for the early intervention of diseases in humans, animals, and plants. However, in-field preparation of high-quality nucleic acids from various specimens for downstream analyses, such as amplification and sequencing, is challenging. Thus, developing and adapting sample lysis and nucleic acid extraction protocols suitable for portable formats have drawn significant attention.

Emerging Technologies for Monitoring Plant Health in Vivo.

In the coming decades, increasing agricultural productivity is all-important. As the global population is growing rapidly and putting increased demand on food supply, poor soil quality, drought, flooding, increasing temperatures, and novel plant diseases are negatively impacting yields worldwide. One method to increase yields is plant health monitoring and rapid detection of disease, nutrient deficiencies, or drought.

Laser-etched grooves for rapid fluid delivery for a paper-based chemiresistive biosensor.

Paper-based microfluidic devices are an attractive option for developing low-cost, point-of-care diagnostic tools. To incorporate more complex assays into paper, these devices must become more sophisticated, through the sequential delivery of different liquids or reagents without user intervention. Many flow control strategies focus on slowing the fluid down.

Recent developments in flow modeling and fluid control for paper-based microfluidic biosensors.

Over the last 10 years, researchers have shown that paper is a promising substrate for affordable biosensors. The field of paper-microfluidics has evolved rapidly in that time, with simple colorimetric assays giving way to more complex electrochemical devices that can handle multiple samples at a given time. As paper devices become more complex, the ability to precisely control different fluids simultaneously becomes a challenge.

An origami electrical biosensor for multiplexed analyte detection in body fluids.

We developed an affordable, highly sensitive, and specific paper-based microfluidic platform for fast multiplexed detections of important biomarkers in various body fluids, including urine, saliva, serum, and whole blood. The sensor array consisted of five individual sensing channels with various functionalities that only required a micro liter-sized sample, which was equally split into aliquots by the built-in paper microfluidics. We achieved the individual functionalizations of various bioreceptors by employing the use of wax barriers and 'paper bridges' in an easy and low-cost manner.

Modifying Wicking Speeds in Paper-Based Microfluidic Devices by Laser-Etching.

Paper-based microfluidic devices are an attractive platform for developing low-cost, point-of-care diagnostic tools. As paper-based devices' detection chemistries become more complex, more complicated devices are required, often entailing the sequential delivery of different liquids or reagents to reaction zones. Most research into flow control has been focused on introducing delays.

Distance and Microsphere Aggregation-Based DNA Detection in a Paper-Based Microfluidic Device.

In paper-based microfluidics, the simplest devices are colorimetric, giving qualitative results. However, getting quantitative data can be quite a bit more difficult. Distance-based devices provide a user-friendly means of obtaining quantitative data without the need for any additional equipment, simply by using an included ruler or calibrated markings.

Massively-Parallelized, Deterministic Mechanoporation for Intracellular Delivery.

Microfluidic intracellular delivery approaches based on plasma membrane poration have shown promise for addressing the limitations of conventional cellular engineering techniques in a wide range of applications in biology and medicine. However, the inherent stochasticity of the poration process in many of these approaches often results in a trade-off between delivery efficiency and cellular viability, thus potentially limiting their utility. Herein, we present a novel microfluidic device concept that mitigates this trade-off by providing opportunity for deterministic mechanoporation (DMP) of cells en masse.

Meso-Scale Particle Image Velocimetry Studies of Neurovascular Flows In Vitro.

Particle image velocimetry (PIV) is used in a wide variety of fields, due to the opportunity it provides for precisely visualizing and quantifying flows across a large spatiotemporal range. However, its implementation typically requires the use of expensive and specialized instrumentation, which limits its broader utility. Moreover, within the field of bioengineering, in vitro flow visualization studies are also often further limited by the high cost of commercially sourced tissue phantoms that recapitulate desired anatomical structures, particularly for those that span the mesoscale regime (i.

A paper-based chemiresistive biosensor employing single-walled carbon nanotubes for low-cost, point-of-care detection.

Paper-based biosensors are promising for low-cost diagnostics. However, its widespread use has been hampered due to a lack of sensitive detection methods that can be easily implemented on paper substrates. On the other hand, single-walled carbon nanotubes (SWNTs) -based chemiresistive biosensors are gaining popularity as label-free, highly sensitive biosensors.

Impact of fluidic agitation on human pluripotent stem cells in stirred suspension culture.

The success of human pluripotent stem cells (hPSCs) as a source of future cell therapies hinges, in part, on the availability of a robust and scalable culture system that can readily produce a clinically relevant number of cells and their derivatives. Stirred suspension culture has been identified as one such promising platform due to its ease of use, scalability, and widespread use in the pharmaceutical industry (e.g.

Polydiacetylene-Coated Sensor Strip for Immunochromatic Detection of Xylella fastidiosa subsp. fastidiosa.

This study presents a sensor strip for user-friendly, naked-eye detection of Xylella fasitdiosa, the bacterial causal agent of Pierce's disease in grapevine. This sensor uses anti- X. fastidiosa antibodies conjugated to a polydiacetylene layer on a polyvinylidene fluoride strip to generate specific color transitions and discriminate levels of the pathogen.

Polydiacetylene-coated polyvinylidene fluoride strip aptasensor for colorimetric detection of zinc(II).

We report a new polydiacetylene (PDA) sensor strip for simple visual detection of zinc ions in aqueous solution. The specificity of this sensor comes from Zn DNA aptamer probes conjugated onto PDA. Effects of aptamer length and structure on the sensitivity of PDA's color transition were first investigated.

Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices.

We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol adhesive through a metal stencil, the overall amount of adhesive used in assembling paper microfluidic devices can be significantly reduced. We show on a simple 4-layer planar paper microfluidic device that the optimal adhesive application technique and device construction style depends heavily on desired performance characteristics.

In Planta Microsphere-Based Lateral Flow Leaf Biosensor in Maize.

Low-cost and quick detection of biotic stresses is critically important for protection of staple food crops such as maize in smallholder farms in developing countries, where access to improved seed varieties, fertilizers, and pesticides is limited due to financial and geographical reasons. Here, we report a new lateral flow detection technology directly integrated in a maize leaf, in which microspheres conjugated with analyte-specific capture antibodies are non-invasively injected. The antibody-conjugated microspheres capture and detect an analyte in a concentration-specific manner.

Patterned adhesive enables construction of nonplanar three-dimensional paper microfluidic circuits.

This article discusses the fabrication of planar and nonplanar 3D paper microfluidic circuits through the use of patterned spray adhesive application and origami techniques. The individual paper layers are held together via semi-permanent adhesive bonds without the need for external clamps. Semi-permanent bonds accommodate the repeated folding and unfolding required by complex origami device structures and allow the device to be unfolded post-use to view internally displayed results.

Pathophysiology and treatment of patients with globus sensation--from the viewpoint of esophageal motility dysfunction.

"Globus sensation" is often described as the sensation of a lump in the throat associated with dry swallowing or the need for dry swallowing, which disappears completely during eating or drinking and for which no organic cause can be established. Due to the uncertain etiology of "globus sensation", it remains difficult to establish standard treatment strategies for affected patients. Lately most attention has been focused on gastroesophageal reflux disease and several reports have indicated that there is a close relationship between esophageal acid reflux and globus sensation.

Engineered micromechanical cues affecting human pluripotent stem cell regulations and fate.

The survival, growth, self-renewal, and differentiation of human pluripotent stem cells (hPSCs) are influenced by their microenvironment, or so-called "niche," consisting of particular chemical and physical cues. Previous studies on mesenchymal stem cells and other stem cells have collectively uncovered the importance of physical cues and have begun to shed light on how stem cells sense and process such cues. In an attempt to support similar progress in mechanobiology of hPSCs, we review mechanosensory machinery, which plays an important role in cell-extracellular matrix interactions, cell-cell interactions, and subsequent intracellular responses.

Esophageal motor dysfunction plays a key role in GERD with globus sensation--analysis of factors promoting resistance to PPI therapy.

Objective: Patients with gastroesophageal reflux disease (GERD) also have various extra-esophageal symptoms. Laryngopharyngeal reflux disease (LPRD) is a subtype of GERD associated with globus sensation, but proton pump inhibitor (PPI) therapy achieves disappointing results. This study investigated esophageal motility in GERD patients with globus sensation who were resistant to PPI therapy.

Usefulness of endoscopic brushing and magnified endoscopy with narrow band imaging (ME-NBI) to detect intestinal phenotype in columnar-lined esophagus.

Background: Barrett's esophagus with specialized intestinal metaplasia (SIM), which is at high risk of progressing to esophageal adenocarcinoma, has been identified by obtaining biopsy specimens randomly. Magnified endoscopy with narrow band imaging (ME-NBI) is reported to be useful for detecting SIM or the intestinal phenotype. We aimed to evaluate the usefulness of endoscopic brushing followed by ME-NBI for the detection of the intestinal phenotype.

Developing defined culture systems for human pluripotent stem cells.

Human pluripotent stem cells hold promising potential in many therapeutics applications including regenerative medicine and drug discovery. Over the past three decades, embryonic stem cell research has illustrated that embryonic stem cells possess two important and distinct properties: the ability to continuously self-renew and the ability to differentiate into all specialized cell types. In this article, we will discuss the continuing evolution of human pluripotent stem cell culture by examining requirements needed for the maintenance of self-renewal in vitro.

An optimized small molecule inhibitor cocktail supports long-term maintenance of human embryonic stem cells.

A major challenge in stem cell-mediated regenerative medicine is the development of defined culture systems for the maintenance of clinical-grade human embryonic stem (hES) cells. Here, we identify, using a feedback system control scheme, a unique combination of three small molecule inhibitors that enables the maintenance of hES cells on a fibronectin-coated surface through single cell passaging. After 20 passages, the undifferentiated state of the hES cells was confirmed by OCT4, SSEA4 and NANOG expressions, whereas their pluripotent potential and genetic integrity were demonstrated by teratoma formation and normal karyotype, respectively.

Efficient dielectrophoretic patterning of embryonic stem cells in energy landscapes defined by hydrogel geometries.

In this study, we have developed an integrated microfluidic platform for actively patterning mammalian cells, where poly(ethylene glycol) (PEG) hydrogels play two important roles as a non-fouling layer and a dielectric structure. The developed system has an embedded array of PEG microwells fabricated on a planar indium tin oxide (ITO) electrode. Due to its dielectric properties, the PEG microwells define electrical energy landscapes, effectively forming positive dielectrophoresis (DEP) traps in a low-conductivity environment.