Optical Adhesion Control of Hydrogel Microtools for On-Demand Immobilization and Measurement of Cells on a Microfluidic Chip

2010 ◽  
Vol 22 (5) ◽  
pp. 631-638 ◽  
Author(s):  
Hisataka Maruyama ◽  
◽  
Toshio Fukuda ◽  
Fumihito Arai ◽  
Keyword(s):  
Optical Tweezers ◽  
Microfluidic Chip ◽  
Electrolyte Concentration ◽  
Ph Value ◽  
Uv Light ◽  
Yeast Cells ◽  
Light Illumination ◽  
Local Conditions ◽  
On Demand ◽  
Adhesion Control

Optical adhesion control of hydrogel microtools, made of hydrophilic photo-crosslinkable resin, was developed for on-demand immobilization and measurement of cells on a microfluidic chip. The hydrogel microtool was manipulated by optical tweezers and modified by spiropyran chromospheres, which was a photochromic polymer. We developed on-demand control of uni/bidirectional adhesiveness of the microtool by control of electrolyte concentration in a solution. Photo illumination controls the adhesiveness of the microtools. In case of unidirectional control of adhesiveness, the microtools adhere to glass, other microtools and cells by illumination of ultraviolet (UV) light. Spiropyran chromospheres were used for bidirectional control of adhesiveness to cell. In case of bidirectional control of adhesiveness, the microtools adhere to cells by UV illumination. On the other hand, the microtool detaches from the adhered cells by visible (VIS) light illumination. Electrolyte concentration in the solution controlled these adhesiveness controls. Adherence of the microtool was enough to keep its position on a microfluidic chip. We applied these immobilization methods to measure the local conditions around cells by modifying the microtool with a pH indicator, bromothymol blue (BTB). Local measurements of the ambient pH value of yeast cells were performed by immobilizing the cell on the surface of the pH sensing microtool. Moreover, culture monitoring of a single yeast cell was demonstrated by immobilization to the microtool.

scholarly journals Engineered Th17 cell differentiation using a photo-activatable immune modulator

2019 ◽  
Author(s):  
Bibudha Parasar ◽  
Pamela V. Chang
Keyword(s):  
Cell Differentiation ◽  
Th17 Cell ◽  
Th17 Cells ◽  
Uv Light ◽  
T Cell Subsets ◽  
Light Illumination ◽  
Immune Modulator ◽  
On Demand ◽  
Th17 Cell Differentiation

AbstractT helper 17 (Th17) cells, an important subset of CD4+ T cells, help to eliminate extracellular infectious pathogens that have invaded our tissues. Despite the critical roles of Th17 cells in immunity, how the immune system regulates the production and maintenance of this cell type remains poorly understood. In particular, the plasticity of these cells, or their dynamic ability to trans-differentiate into other CD4+ T cell subsets, remains mostly uncharacterized. Here, we report a synthetic immunology approach using a photo-activatable immune modulator (PIM) to increase Th17 cell differentiation on demand with spatial and temporal precision to help elucidate this important and dynamic process. In this chemical strategy, we developed a latent agonist that, upon photochemical activation, releases a small-molecule ligand that targets the aryl hydrocarbon receptor (AhR) and ultimately induces Th17 cell differentiation. We used this chemical tool to control AhR activation with spatiotemporal precision within cells and to modulate Th17 cell differentiation on demand by using UV light illumination. We envision that this approach will enable an understanding of the dynamic functions and behaviors of Th17 cells in vivo during immune responses and in mouse models of inflammatory disease.

scholarly journals Electrolyte Concentration Effect of a Photoelectrochemical Cell Consisting of TiO2 Nanotube Anode

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Kai Ren ◽  
Yong X. Gan ◽  
Efstratios Nikolaidis ◽  
Sharaf Al Sofyani ◽  
Lihua Zhang
Keyword(s):  
Open Circuit Voltage ◽  
Electrolyte Concentration ◽  
Uv Light ◽  
Photocurrent Density ◽  
High Viscosity ◽  
Open Circuit ◽  
Photoelectrochemical Cell ◽  
Concentration Effect ◽  
Light Illumination ◽  
Applied Bias Voltage

The photoelectrochemical responses of a TiO2 nanotube anode in ethylene glycol (EG), glycerol, ammonia, ethanol, urea, and Na2S electrolytes with different concentrations were investigated. The TiO2 nanotube anode was highly efficient in photoelectrocatalysis in these solutions under UV light illumination. The photocurrent density is obviously affected by the concentration change. Na2S generated the highest photocurrent density at 0, 1, and 2 V bias voltages, but its concentration does not significantly affect the photocurrent density. Urea shows high open circuit voltage at proper concentration and low photocurrent at different concentrations. Externally applied bias voltage is also an important factor that changes the photoelectrochemical reaction process. In view of the open circuit voltage, EG, ammonia, and ethanol fuel cells show the trend that the open circuit voltage (OCV) increases with the increase of the concentration of the solutions. Glycerol has the highest OCV compared with others, and it deceases with the increase in the concentration because of the high viscosity. The OCV of the urea and Na2S solutions did not show obvious concentration effect.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

scholarly journals Optical vortex lattice: an exploitation of orbital angular momentum

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Liuhao Zhu ◽  
Miaomiao Tang ◽  
Hehe Li ◽  
Yuping Tai ◽  
Xinzhong Li
Keyword(s):  
Angular Momentum ◽  
Optical Tweezers ◽  
Orbital Angular Momentum ◽  
Vortex Lattice ◽  
Optical Vortex ◽  
Yeast Cells ◽  
Particle Manipulation ◽  
Complex Motion ◽  
Potential Applications ◽  
Vortex Beams

Abstract Generally, an optical vortex lattice (OVL) is generated via the superposition of two specific vortex beams. Thus far, OVL has been successfully employed to trap atoms via the dark cores. The topological charge (TC) on each optical vortex (OV) in the lattice is only ±1. Consequently, the orbital angular momentum (OAM) on the lattice is ignored. To expand the potential applications, it is necessary to rediscover and exploit OAM. Here we propose a novel high-order OVL (HO-OVL) that combines the phase multiplication and the arbitrary mode-controllable techniques. TC on each OV in the lattice is up to 51, which generates sufficient OAM to manipulate microparticles. Thereafter, the entire lattice can be modulated to desirable arbitrary modes. Finally, yeast cells are trapped and rotated by the proposed HO-OVL. To the best of our knowledge, this is the first realization of the complex motion of microparticles via OVL. Thus, this work successfully exploits OAM on OVL, thereby revealing potential applications in particle manipulation and optical tweezers.

Optic and Piezoelectric Coupling in the Sol-Gel PLZT Electroceramics

2012 ◽  
Vol 730-732 ◽  
pp. 129-134
Author(s):  
Lucjan Kozielski ◽  
Malgorzata Plonska
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Light Illumination ◽  
Piezoelectric Effects ◽  
Piezoelectric Coupling ◽  
Wireless Device ◽  
Organometallic Precursors ◽  
Gain Adjustment ◽  
Piezoelectric Transformers ◽  
Sintering Method

PZT ceramic system with presence of La contents, have been proposed and prepared using sol gel sintering method for practical application of photostriction, which is the superposition of photovoltaic and piezoelectric effects. Such a ceramics produced by conventional mixing oxide method does not exhibit photostrictive properties due to the defects and inhomogeneous distribution of grains and pores. In this study, an investigated lanthanium(III) doped PZT ceramics were obtained by sol-gel technique from the organometallic precursors. It was found that fabricated material were effective in the enhancement of photovoltaic and photostrictive properties. Consequently, lanthanium influence deviation of piezoelectric parameters were studied as a function UV light illumination. For the determination lighting dependancy of the transformation parameters the resonant and antiresonant method was implemented. The improved Piezoelectric Transformer structure successfully changed gain characteristics proportionally to light intensity. The authors invention of a light driven output gain adjustment in Piezoelectric Transformers (PT) yields a novel “smart” multifunctional wireless device. This new created application area can be utilized in self-adopting shutters in photo cameras due to improved sensitivity to surrounding illumination conditions.

Light-induced change of the molecular charge in a spironaphthoxazine compound

1993 ◽  
Vol 71 (11) ◽  
pp. 1828-1833 ◽  
Author(s):  
Paul Rys ◽  
Ruth Weber ◽  
Qinglan Wu
Keyword(s):  
Flash Photolysis ◽  
Ph Value ◽  
Uv Light ◽  
Merocyanine Form ◽  
Acid Base ◽  
Experimental Conditions ◽  
Base Equilibrium ◽  
Acid Base Equilibrium ◽  
Molecular Charge ◽  
Spiro Form

To evaluate the experimental conditions for the light-induced change of the molecular charge, the dependence of the photochromic reaction behaviour of the indolino spiro naphthoxazine compound 1,3,3-trimethyl-spiro[2H-indol 2,3′-[3H]naphth[2,1-b]-[1,4]oxazine] on the pH value of the solution is investigated. In the absence of UV light an acid–base equilibrium between the spiro form and a protonated closed form is established. By irradiation under appropriate acidic conditions the spiro form can be transformed into an open cationic form through the merocyanine form. Between the two open forms an acid–base equilibrium is established. Except for the closed protonated form the structures are confirmed by mean of NMR. The kinetics of the thermal ring-closing reaction of both forms are investigated by flash photolysis. It is shown that the ring-closing reaction proceeds exclusively via the merocyanine form. The pK values determined for both equilibria give the pH range, in which the light-induced change of the molecular charge occurs.

scholarly journals The pH Value Control of Morphology and Luminescence Properties of Gd2O2S: Tb3+ Phosphors

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 646
Author(s):  
Peng Jiang ◽  
Zhipeng Li ◽  
Wei Lu ◽  
Yi Ma ◽  
Wenhuai Tian
Keyword(s):  
Electron Beam ◽  
Rare Earth ◽  
Ph Value ◽  
Uv Light ◽  
Hexagonal Phase ◽  
Band Gap Energy ◽  
Information Storage ◽  
Luminescence Properties ◽  
Research Fields ◽  
Rare Earth Doped

Developing rare-earth doped oxysulfide phosphors with diverse morphologies has significant value in many research fields such as in displays, medical diagnosis, and information storage. All of the time, phosphors with spherical morphology have been developed in most of the related literatures. Herein, by simply adjusting the pH values of the reaction solution, Gd2O2S:Tb3+ phosphors with various morphologies (sphere-like, sheet-like, cuboid-like, flat square-like, rod-like) were synthesized. The XRD patterns showed that phosphors with all morphologies are pure hexagonal phase of Gd2O2S. The atomic resolution structural analysis by transmission electron microscopy revealed the crystal growth model of the phosphors with different morphology. With the morphological change, the band gap energy of Gd2O2S:Tb3+ crystal changed from 3.76 eV to 4.28 eV, followed by different luminescence performance. The samples with sphere-like and cuboid-like microstructures exhibit stronger cathodoluminescence intensity than commercial product by comparison. Moreover, luminescence of Gd2O2S:Tb3+ phosphors have different emission performance excited by UV light radiation and an electron beam, which when excited by UV light is biased towards yellow, and while excited by an electron beam is biased towards cyan. This finding provides a simple but effective method to achieve rare-earth doped oxysulfide phosphors with diversified and tunable luminescence properties through morphology control.

NAB2: a yeast nuclear polyadenylated RNA-binding protein essential for cell viability

1993 ◽  
Vol 13 (5) ◽  
pp. 2730-2741 ◽  
Author(s):  
J T Anderson ◽  
S M Wilson ◽  
K V Datar ◽  
M S Swanson
Keyword(s):  
Rna Binding ◽  
Uv Light ◽  
Polyclonal Antibodies ◽  
Yeast Cells ◽  
Binding Studies ◽  
Single Stranded Dna ◽  
Binding Motifs ◽  
Polyadenylated Rna ◽  
Nuclear Rna

A variety of nuclear ribonucleoproteins are believed to associate directly with nascent RNA polymerase II transcripts and remain associated during subsequent nuclear RNA processing reactions, including pre-mRNA polyadenylation and splicing as well as nucleocytoplasmic mRNA transport. To investigate the functions of these proteins by using a combined biochemical and genetic approach, we have isolated nuclear polyadenylated RNA-binding (NAB) proteins from Saccharomyces cerevisiae. Living yeast cells were irradiated with UV light to covalently cross-link proteins intimately associated with RNA in vivo. Polyadenylated RNAs were then selectively purified, and the covalent RNA-protein complexes were used to elicit antibodies in mice. Both monoclonal and polyclonal antibodies which detect a variety of NAB proteins were prepared. Here we characterize one of these proteins, NAB2. NAB2 is one of the major proteins associated with nuclear polyadenylated RNA in vivo, as detected by UV light-induced cross-linking. Cellular immunofluorescence, using both monoclonal and polyclonal antibodies, demonstrates that the NAB2 protein is localized within the nucleus. The deduced primary structure of NAB2 indicates that it is composed of at least two distinct types of RNA-binding motifs: (i) an RGG box recently described in a variety of heterogeneous nuclear RNA-, pre-rRNA-, mRNA-, and small nucleolar RNA-binding proteins and (ii) CCCH motif repeats related to the zinc-binding motifs of the largest subunit of RNA polymerases I, II, and III. In vitro RNA homopolymer/single-stranded DNA binding studies indicate that although both the RGG box and CCCH motifs bind poly(G), poly(U), and single-stranded DNA, the CCCH motifs also bind to poly(A). NAB2 is located on chromosome VII within a cluster of ribonucleoprotein genes, and its expression is essential for cell growth.

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