Search results for "Fluidics"
showing 10 items of 131 documents
Production of polymeric micro- and nanostructures with tunable properties as pharmaceutical delivery systems
2020
Abstract The production of novel graft copolymers based on poly-e-caprolactone (PCL) and polyaspartamide are useful to realize structures for potential biomedical applications. Here, the synthesis of pegylated PCL/polyhydroxyethyl aspartamide (PHEA) graft copolymers (PHEA-g-SUCC-PCL-g-PEG) with tunable composition, was achieved by followpling a synthetic strategy that involved first the grafting of preformed PCL on PHEA backbone, then polyethylen glycol (PEG), by using 1,1′-carbonyldiimidazole (CDI) to speed up the condensation reaction. Graft copolymers with a Derivatization Degree (DD) in PCL ranging between 1.1 and 4.4 mol% were obtained, and processable with different technologies for t…
Optofluidic taming of a colloidal dimer with a silicon nanocavity
2014
International audience; We report here the optical trapping of a heterogeneous colloidal dimer above a photonic crystal nanocavity used as an on-chip optical tweezer. The trapped dimer consists of a cluster of two dielectric microbeads of different sizes linked by van der Waals forces. The smallest bead, 1 μm in diameter, is observed to be preferentially trapped by the nanotweezer, leaving the second bead untrapped. The rotational nature of the trapped dimer Brownian motion is first evidenced. Then, in the presence of a fluid flow, control of its orientation and rotation is achieved. The whole system is found to show high rotational degrees of freedom, thereby acting as an effective flow-se…
Neurohybrid Memristive CMOS-Integrated Systems for Biosensors and Neuroprosthetics
2020
Here we provide a perspective concept of neurohybrid memristive chip based on the combination of living neural networks cultivated in microfluidic/microelectrode system, metal-oxide memristive devices or arrays integrated with mixed-signal CMOS layer to control the analog memristive circuits, process the decoded information, and arrange a feedback stimulation of biological culture as parts of a bidirectional neurointerface. Our main focus is on the state-of-the-art approaches for cultivation and spatial ordering of the network of dissociated hippocampal neuron cells, fabrication of a large-scale cross-bar array of memristive devices tailored using device engineering, resistive state program…
Fabrication of a negative PMMA master mold for soft-lithography by MeV ion beam lithography
2012
Abstract In this study, poly(methyl methacrylate) (PMMA) was investigated as a negative resist by irradiation with a high-fluence 2 MeV proton beam. The beam from a 1.7 MV Tandetron accelerator at the Plasma and Beam Physics Research Facility (PBP) of Chiang Mai University is shaped by a pair of computer-controlled L-shaped apertures which are used to expose rectangular pattern elements with 1–1000 μm side length. Repeated exposure of rectangular pattern elements allows a complex pattern to be built up. After subsequent development, the negative PMMA microstructure was used as a master mold for casting poly(dimethylsiloxane) (PDMS) following a standard soft-lithography process. The PDMS chi…
Development of elastomeric lab-on-a-chip devices through Proton Beam Writing (PBW) based fabrication strategies
2009
Abstract In recent years, one of the most exciting developments in fluidic device applications is the rapid evolution of miniaturized micro- and nanofluidic systems, the so called “lab-on-a-chip” devices. These devices integrate laboratory functions into a single chip, and are capable of various biochemical analysis and synthesis, such as sample injection and preparation, single cell/molecule observation, bioparticle sequencing and sorting etc. The evolvement of lab-on-a-chip concept implies the use of novel fabrication techniques for the construction of versatile analytical components in a fast and reproducible manner. Endowed with unique three-dimensional fabrication abilities, Proton Bea…
Development of procedures for programmable proximity aperture lithography
2013
Abstract Programmable proximity aperture lithography (PPAL) with MeV ions has been used in Jyvaskyla and Chiang Mai universities for a number of years. Here we describe a number of innovations and procedures that have been incorporated into the LabView-based software. The basic operation involves the coordination of the beam blanker and five motor-actuated translators with high accuracy, close to the minimum step size with proper anti-collision algorithms. By using special approaches, such writing calibration patterns, linearisation of position and careful backlash correction the absolute accuracy of the aperture size and position, can be improved beyond the standard afforded by the repeata…
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 …