A traveling surface acoustic wave-based micropiezoactuator: A tool for additive- and label-free cell lysis.

We propose a traveling surface acoustic wave (TSAW)-based microfluidic method for cell lysis that enables lysis of any biological entity, without the need for additional additives. Lysis of cells in the sample solution flowing through a poly (dimethyl siloxane) microchannel is enabled by the interaction of cells with TSAWs propagated from gold interdigitated transducers (IDTs) patterned onto a LiNbO piezoelectric substrate, onto which the microchannel was also bonded. Numerical simulations to determine the wave propagation intensities with varying parameters including IDT design, supply voltage, and distance of the channel from the IDT were performed.

A multiplex Taqman PCR assay for MRSA detection from whole blood.

Methicillin-resistant Staphylococcus aureus (MRSA) causes a wide range of hospital and community-acquired infections worldwide. MRSA is associated with worse clinical outcomes that can lead to multiple organ failure, septic shock, and death, making timely diagnosis of MRSA infections very crucial. In the present work, we develop a method that enables the positive enrichment of bacteria from spiked whole blood using protein coated magnetic beads, followed by their lysis, and detection by a real-time multiplex PCR directly.

Dean migration of unfocused micron sized particles in low aspect ratio spiral microchannels.

We present an analysis of the microfluidic Dean migration of 2.5 µm particles, which do not meet focus criterion, in tall and low aspect ratio microchannels. We demonstrate the use of such low aspect ratio and tall spirals (h > 50 µm) for isolating high concentration (> 10 particles or cells/mL) micron sized particles without an initial off-chip dilution step.

Isolation of Single Intracellular Bacterial Communities Generated from a Murine Model of Urinary Tract Infection for Downstream Single-cell Analysis.

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected in the urinary tract. The protocol can be broadly divided into three sections: the infection, bladder epithelial cell harvesting, and mouth micropipetting to isolate individual infected epithelial cells. The isolated epithelial cell contains viable bacterial cells and is nearly free of contaminating extracellular bacteria, making it ideal for downstream single-cell analysis.

Purification of Intracellular Bacterial Communities during Experimental Urinary Tract Infection Reveals an Abundant and Viable Bacterial Reservoir.

Urinary tract infections (UTIs) are a major infection of humans, particularly affecting women. Recurrent UTIs can cause significant discomfort and expose patients to high levels of antibiotic use, which in turn contributes to the development of higher antibiotic resistance rates. Most UTIs are caused by uropathogenic , which is able to form intracellular collections (termed intracellular bacterial communities [IBCs]) within the epithelial cells lining the bladder lumen.

Controlling bubbles using bubbles--microfluidic synthesis of ultra-small gold nanocrystals with gas-evolving reducing agents.

Microfluidic wet-chemical synthesis of nanoparticles is a growing area of research in chemical microfluidics, enabling the development of continuous manufacturing processes that overcome the drawbacks of conventional batch-based synthesis methods. The synthesis of ultra-small (<5 nm) metallic nanocrystals is an interesting area with many applications in diverse fields, but is typically very challenging to accomplish in a microfluidics-based system due to the use of a strong gas-evolving reducing agent, aqueous sodium borohydride (NaBH(4)), which causes uncontrolled out-gassing and bubble formation, flow disruption and ultimately reactor failure. Here we present a simple method, rooted in the concepts of multiphase mass transfer that completely overcomes this challenge-we simply inject a stream of inert gas bubbles into our channels that essentially capture the evolving gas from the reactive aqueous solution, thereby preventing aqueous dissolved gas concentration from reaching the solubility threshold for bubble nucleation.

Plasmonic nanoshell synthesis in microfluidic composite foams.

The availability of robust, scalable, and automated nanoparticle manufacturing processes is crucial for the viability of emerging nanotechnologies. Metallic nanoparticles of diverse shape and composition are commonly manufactured by solution-phase colloidal chemistry methods, where rapid reaction kinetics and physical processes such as mixing are inextricably coupled, and scale-up often poses insurmountable problems. Here we present the first continuous flow process to synthesize thin gold "nanoshells" and "nanoislands" on colloidal silica surfaces, which are nanoparticle motifs of considerable interest in plasmonics-based applications.

Ionic liquid-based compound droplet microfluidics for 'on-drop' separations and sensing.

We present a new and general scheme for analytical applications of droplet-based microfluidics in which flowing droplets function not only as isolated reaction flasks, but are also capable of on-drop separation and sensing. To demonstrate this, we choose ionic liquids as designer fluids whose chemical and physical properties can be tailored in task-specific fashion. We create aqueous-ionic liquid compound droplets with tunable structures using an imidazolium-based ionic liquid, and present two analytical applications-separation of a binary aqueous mixture of organic dyes and dynamic pH sensing-to highlight the salient features of this scheme.

Droplet-based microfluidic synthesis of anisotropic metal nanocrystals.

A droplet-based microfluidic method for the preparation of anisotropic gold nanocrystal dispersions is presented. Gold nanoparticle seeds and growth reagents are dispensed into monodisperse picoliter droplets within a microchannel. Confinement within small droplets prevents contact between the growing nanocrystals and the microchannel walls.

Microfluidic emulsions with dynamic compound drops.

We demonstrate a new class of microfluidic emulsion where the 'drops' of the emulsion are dynamic reversible bubble-drop pairs, with potential applications in microfluidic technology for chemical synthesis, molecular separations and screening.