Optofluidic paper-based analytical device for discriminative detection of organic substances via digital color coding.

Developing a portable yet affordable method for the discrimination of chemical substances with good sensitivity and selectivity is essential for on-site visual detection of unknown substances. Herein, we propose an optofluidic paper-based analytical device (PAD) that consists of a macromolecule-driven flow (MDF) gate and photonic crystal (PhC) coding units, enabling portable and scalable detection and discrimination of various organic chemical, mimicking the olfactory system. The MDF gate is designed for precise flow control of liquid analytes, which depends on intermolecular interactions between the polymer at the MDF gate and the liquid analytes.

A Facile Method to Fabricate an Enclosed Paper-Based Analytical Device via Double-Sided Patterning for Ionic Contaminant Detection.

Microfluidic paper-based analytical devices (μPADs) have been developed for use in a variety of diagnosis and analysis fields. However, conventional μPADs with an open-channel system have limitations for application as analytical platforms mainly because of the evaporation and contamination of the sample solution. This study demonstrates the design and fabrication of an enclosed three-dimensional(3D)-μPAD and its application as a primary early analysis platform for ionic contaminants.

Recent Developments in Bacterial Chemotaxis Analysis Based on the Microfluidic System.

Bacterial motility in response to chemicals, also called bacterial chemotaxis, is a critical ability to search for the optimal environment to ensure the survival of bacterial species. Recent advances in microbiology have allowed the engineering of bacterial chemotactic properties. Conventional methods for characterizing bacterial motility are not able to fully monitor chemotactic behavior.

Large-scale production of compound bubbles using parallelized microfluidics for efficient extraction of metal ions.

Correction for 'Large-scale production of compound bubbles using parallelized microfluidics for efficient extraction of metal ions' by Heon-Ho Jeong et al., Lab Chip, 2019, 19, 665-673.

Large-scale production of compound bubbles using parallelized microfluidics for efficient extraction of metal ions.

Recent advances in microfluidic technologies have enabled production of micro-scale compound bubbles that consist of gaseous cores surrounded by thin liquid shells, achieving control and uniformity not possible using conventional techniques. These compound bubbles have demonstrated enormous utility as functional materials for drug delivery, as ultra-lightweight structural materials, as engineered acoustic materials, and also as separating agents for extraction of metal ions from waste fluid streams. Despite these successful demonstrations, compound bubbles have largely remained at the laboratory-scale due to the slow production rates endemic to microfluidics (<10 mL h-1).

Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip.

Polydimethyl-siloxane (PDMS) is often applied to fabricate cell chips. In this study, we fabricated an adipocyte microcell pattern chips using PDMS to analyze the inhibition activity of lipid droplets in mouse embryo fibroblast cells (3T3-L1) with anti-obesity agents. To form the PDMS based micropattern, we applied the micro-contact printing technique using PDMS micro-stamps that had been fabricated by conventional soft lithography.

Injectable Granular Hydrogels with Multifunctional Properties for Biomedical Applications.

Injectable hydrogels are useful for numerous biomedical applications, such as to introduce therapeutics into tissues or for 3D printing. To expand the complexity of available injectable hydrogels, shear-thinning and self-healing granular hydrogels are developed from microgels that interact via guest-host chemistry. The microgel properties (e.

Silicon and glass very large scale microfluidic droplet integration for terascale generation of polymer microparticles.

Microfluidic chips can generate emulsions, which can be used to synthesize polymer microparticles that have superior pharmacological performance compared to particles prepared by conventional techniques. However, low production rates of microfluidics remains a challenge to successfully translate laboratory discoveries to commercial manufacturing. We present a silicon and glass device that incorporates an array of 10,260 (285 × 36) microfluidic droplet generators that uses only a single set of inlets and outlets, increasing throughput by >10,000× compared to microfluidics with a single generator.

Ultra-high throughput detection (1 million droplets per second) of fluorescent droplets using a cell phone camera and time domain encoded optofluidics.

Droplet-based assays-in which ultra-sensitive molecular measurements are made by performing millions of parallel experiments in picoliter droplets-have generated enormous enthusiasm due to their single molecule resolution and robustness to reaction conditions. These assays have great untapped potential for point of care diagnostics but are currently confined to laboratory settings due to the instrumentation necessary to serially generate, control, and measure tens of millions of droplets. To address this challenge, we have developed the microdroplet megascale detector (μMD) that can generate and detect the fluorescence of millions of droplets per second (1000× faster than conventional approaches) using only a conventional cell phone camera.

On-chip analysis, indexing and screening for chemical producing bacteria in a microfluidic static droplet array.

Economic production of chemicals from microbes necessitates development of high-producing strains and an efficient screening technology is crucial to maximize the effect of the most popular strain improvement method, the combinatorial approach. However, high-throughput screening has been limited for assessment of diverse intracellular metabolites at the single-cell level. Herein, we established a screening platform that couples a microfluidic static droplet array (SDA) and an artificial riboswitch to analyse intracellular metabolite concentration from single microbial cells.

A highly addressable static droplet array enabling digital control of a single droplet at pico-volume resolution.

Droplet-based microfluidics enabling exquisite liquid-handling has been developed for diagnosis, drug discovery and quantitative biology. Compartmentalization of samples into a large number of tiny droplets is a great approach to perform multiplex assays and to improve reliability and accuracy using a limited volume of samples. Despite significant advances in microfluidic technology, individual droplet handling in pico-volume resolution is still a challenge in obtaining more efficient and varying multiplex assays.

Monitoring of chromosome dynamics of single yeast cells in a microfluidic platform with aperture cell traps.

Chromosome movement plays important roles in DNA replication, repair, genetic recombination, and epigenetic phenomena during mitosis and meiosis. In particular, chromosome movement in the nuclear space is essential for the reorganization of the nucleus. However, conventional methods for analyzing the chromosome movements in vivo have been limited by technical constraints of cell trapping, cell cultivation, oxygenation, and in situ imaging.

Morphological Control of Cells on 3-Dimensional Multi-Layer Nanotopographic Structures.

The extracellular matrix (ECM) environment is known to play an important role in the process of various cell regulatory mechanisms. We have investigated the ability of 3-dimensional ECM geometries to induce morphological changes in cells. Bi-layer polymeric structures with submicron scale stripe patterns were fabricated using a two-step nano-imprinting technique, and the orientation angle (θ(α)) of the upper layer was controlled by changing its alignment with respect to the orientation of the bottom layer.

Kilo-scale droplet generation in three-dimensional monolithic elastomer device (3D MED).

Droplet-based microfluidics has led to transformational new approaches in diverse areas including materials synthesis and high-throughput biological assays. However, the translation of droplet microfluidics technology into commercial applications requires scale-up of droplet generation from the laboratory (<10 mL h(-1)) to the industrial (>1 L h(-1)) scale. To address this challenge, we develop a three-dimensional monolithic elastomer device (3D MED) for mass production of monodisperse emulsion droplets.

A programmable microfluidic static droplet array for droplet generation, transportation, fusion, storage, and retrieval.

We present a programmable microfluidic static droplet array (SDA) device that can perform user-defined multistep combinatorial protocols. It combines the passive storage of aqueous droplets without any external control with integrated microvalves for discrete sample dispensing and dispersion-free unit operation. The addressable picoliter-volume reaction is systematically achieved by consecutively merging programmable sequences of reagent droplets.

Microfluidic static droplet array for analyzing microbial communication on a population gradient.

Quorum sensing (QS) is a type of cell-cell communication using signal molecules that are released and detected by cells, which respond to changes in their population density. A few studies explain that QS may operate in a density-dependent manner; however, due to experimental challenges, this fundamental hypothesis has never been investigated. Here, we present a microfluidic static droplet array (SDA) that combines a droplet generator with hydrodynamic traps to independently generate a bacterial population gradient into a parallel series of droplets under complete chemical and physical isolation.

A "Light-up" 1D supramolecular nanoprobe for silver ions based on assembly of pyrene-labeled peptide amphiphiles: cell-imaging and antimicrobial activity.

We prepared pyrene-labeled peptide amphiphiles (PAs) consisting of a hydrophobic linear- or branched-alkyl chain (for 1 or 2, respectively) and a hydrophilic histidine-rich peptide of HGGGHGHGGGHG (HG12). Both peptides have a strong tendency to form nanofibrils (NFs) in aqueous media. The resulting histidine-coated NFs show a great binding affinity to Cu as a fluorescence "light-off" sensor.

Effect of temperature on biofilm formation by Antarctic marine bacteria in a microfluidic device.

Polar biofilms have become an increasingly popular biological issue because new materials and phenotypes have been discovered in microorganisms in the polar region. Various environmental factors affect the functionality and adaptation of microorganisms. Because the polar region represents an extremely cold environment, polar microorganisms have a functionality different from that of normal microorganisms.

Pump-less static microfluidic device for analysis of chemotaxis of Pseudomonas aeruginosa using wetting and capillary action.

Bacterial chemotaxis is a complex response to temporal changes of concentrations of chemoeffectors. Conventional methods, including microfluidic approaches, for the precise analysis of bacterial chemotaxis are limited in the accurate control of chemical gradients, low sensitivity, and longer analytical times although the advances in microfluidic technology provide a novel platform. Here, we present a diffusion-based microfluidic device to provide rapid diffusion of chemoeffectors using a liquid-liquid interface, which is a critical advance in the analysis of bacterial chemotaxis.

Profiling surface glycans on live cells and tissues using quantum dot-lectin nanoconjugates.

The surface of mammalian cells is densely coated with complex glycans, which are directly involved in cell-cell or cell-protein interactions that trigger various biological responses. Here, we present a novel glycomics approach that uses quantum dot (Qdot)-lectin nanoconjugates to interrogate the surface glycans of tissues and patterned cells. Our approach allows highly sensitive in situ monitoring of specific lectin-glycan interactions and quantitative information on surface glycans for each examined cell line and tissue.

Microfluidic monitoring of Pseudomonas aeruginosa chemotaxis under the continuous chemical gradient.

This study presents a microfluidic approach for the rapid analysis of bacterial chemotaxis in response to chemical gradients. The diffusional mixing of laminar flow continuously generates a stable chemical gradient in a microfluidic device. For the proof of concept, we have investigated the effects of the attractant peptone and repellent trichloroethylene (TCE) on chemotactic responses of wild type Pseudomonas aeruginosa PAO1 and chemotactic mutant PC4.