Search results for "Microfluidics"

Laser Microdissection of the Alveolar Duct Enables Single-Cell Genomic Analysis

2014

Complex tissues such as the lung are composed of structural hierarchies such as alveoli, alveolar ducts, and lobules. Some structural units, such as the alveolar duct, appear to participate in tissue repair as well as the development of bronchioalveolar carcinoma. Here, we demonstrate an approach to conduct laser microdissection of the lung alveolar duct for single-cell PCR analysis. Our approach involved three steps. The initial preparation used mechanical sectioning of the lung tissue with sufficient thickness to encompass the structure of interest. In the case of the alveolar duct, the precision-cut lung slices were 200µm thick; the slices were processed using near-physiologic conditions…

Core-Shell Microgels with Switchable Elasticity at Constant Interfacial Interaction.

2016

Hydrogels based on poly(N-isopropylacrylamide) (pNIPAAm) exhibit a thermo-reversible volume phase transition from swollen to deswollen states. This change of the hydrogel volume is accompanied by changes of the hydrogel elastic and Young's moduli and of the hydrogel interfacial interactions. To decouple these parameters from one another, we present a class of submillimeter sized hydrogel particles that consist of a thermosensitive pNIPAAm core wrapped by a nonthermosensitive polyacrylamide (pAAm) shell, each templated by droplet-based microfluidics. When the microgel core deswells upon increase of the temperature to above 34 °C, the shell is stretched and dragged to follow this deswelling i…

Tuning the defect configurations in nematic and smectic liquid crystalline shells

2013

Thin liquid crystalline shells surrounding and surrounded by aqueous phases can be conveniently produced using a nested capillary microfluidic system, as was first demonstrated by Fernandez-Nieves et al. in 2007. By choosing particular combinations of stabilizers in the internal and external phases, different types of alignment, uniform or hybrid, can be ensured within the shell. Here, we investigate shells in the nematic and smectic phases under varying boundary conditions, focusing in particular on textural transformations during phase transitions, on the interaction between topological defects in the director field and inclusions in the liquid crystal (LC), and on the possibility to rel…

Microfluidic Synthesis of Actuating Microparticles from a Thiol-Ene Based Main-Chain Liquid Crystalline Elastomer.

2016

In this article the microfluidic synthesis of strongly actuating particles on the basis of a liquid crystalline main-chain elastomer is presented. The synthesis is carried out in a capillary-based co-flow microreactor by photo-initiated thiol-ene click chemistry of a liquid crystalline monomer mixture. These microparticles exhibit a deformation from a spherical to a rod-like shape during the thermal-initiated phase transition of the liquid crystalline elastomer (LCE) at which the particles’ aspect ratio is almost doubled. Repeated contraction cycles confirm the complete reversibility of the particles’ actuation properties. The transition temperature of the LCE, the temperature range of the …

Microactuators from a main-chain liquid crystalline elastomer via thiol–ene “click” chemistry

2013

Recently it has been described that liquid crystalline elastomer (LCE) particles of the side-chain type can be prepared in microfluidic devices. Here we present the preparation of micrometer-sized LCE particles of the main-chain type by thiol–ene chemistry. The LCE particles are UV-crosslinked via thiol–ene click chemistry of the nematic monomer, carrying terminal thiol and ene groups, and non-mesogenic tetrathiol and tetraene crosslinkers. The preparation of the LCE particles with a microfluidic device by a continuous “on the fly” technique allows their fast processing with an irradiation time of less than 2 seconds. The resulting particles undergo a temperature-driven volume change up to …

2017

Micro-fluidic pumps as well as artificial micro-swimmers are conveniently realized exploiting phoretic solvent flows based on local gradients of temperature, electrolyte concentration or pH. We here present a facile micro-photometric method for monitoring pH gradients and demonstrate its performance and scope on different experimental situations including an electro-osmotic pump and modular micro-swimmers assembled from ion exchange resin beads and polystyrene colloids. In combination with the present microscope and DSLR camera our method offers a 2 \mu m spatial resolution at video frame rate over a field of view of 3920x2602 \mu m^2. Under optimal conditions we achieve a pH-resolution of …

Mesoscopic Simulation Methods for Studying Flow and Transport in Electric Fields in Micro- and Nanochannels

2012

In the past decades, several mesoscale simulation techniques have emerged as tools to study hydrodynamic flow phenomena on scales in the range of nanoto micrometers. Examples are Dissipative Particle Dynamics (DPD), Multiparticle Collision Dynamics (MPCD), or Lattice Boltzmann (LB) methods. These methods allow one to access time and length scales which are not yet within reach of atomistic Molecular Dynamics (MD) simulations, often at relatively moderate computational expense. They can be coupled with particle-based (e.g., molecular dynamics) simulation methods for thermally fluctuating nanoscale objects, such as colloids or large molecules. This makes them particularly attractive for the a…

M9_Microfluidics_for_CNT

2018

The droplets in contact coalesce when exposed to DEP filed.

M10_Microfluidics_for_CNT

2018

Droplets are preferentially directed to the channel with higher flow rate in the passive sorting junction. When the droplets are exposed to DEP field, the DEP force pull them to the narrower channel.

M12_Microfluidics_for_CNT

2018

The droplets exchanging in the trap causes visible scattering of the laser beam focused on the droplet. The obvious change of laser light intensity can be used for detection of droplet exchange.