Incorporating Stimuli-Responsive Bacteria in Microfluidic Droplets

2015 ◽  
Author(s):  
Kengelle Q. Chukwurah ◽  
Yaping Yang ◽  
Jian Wang ◽  
Yajun Yan ◽  
Eric C. Freeman
Keyword(s):  
Capillary Tube ◽  
Fluorescent Microscopy ◽  
Low Flow ◽  
Stimuli Responsive ◽  
Buffer Solution ◽  
Microfluidic Droplets ◽  
Cellular Environment ◽  
Droplet Interface Bilayer ◽  
Casamino Acids ◽  
Living Organisms

Model cellular membranes respond to chemical and electrical stimuli, regulating transport and exchange between two neighboring aqueous droplets. This regulated exchange may prove useful for controlling aqueous micro-environments for studying stimuli-responsive encapsulated bacteria. This concept is explored in this work, focusing on characterizing the bacterial response within a synthetic cellular environment. In the droplet interface bilayer (DIB) approach, aqueous micro-droplets deposited in an oil reservoir with dissolved lipids are coated with lipid monolayers and arranged into artificial cellular networks. This approach has been explored for potential use as a biologically-inspired smart material, but new material transduction pathways are necessary. This may be accomplished by combining this bottom-up approach to synthetic biology with living organisms such as stimuli-responsive bacteria. Bacteria encapsulation within the microfluidic droplets begins with a strain of Escherichia coli (E. coli), XL1-Blue. These flagellated bacteria naturally respond and move towards chemoattractants such as casamino acids, and their motion may be tracked through differential interference contrast (DIC) and fluorescent microscopy. Chemotaxis of XL1-Blue was assessed through low-flow perfusion of the chemoattractant (casamino acids) into a buffer solution containing the bacteria through a tailored capillary tube. Next, the response of bacteria within asymmetric DIB networks separating the bacteria and the chemoattractant were studied.

scholarly journals Green Plasmonic Nanoparticles and Bio-Inspired Stimuli-Responsive Vesicles in Cancer Therapy Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1083 ◽  
Author(s):  
Valeria De Matteis ◽  
Loris Rizzello ◽  
Mariafrancesca Cascione ◽  
Eva Liatsi-Douvitsa ◽  
Azzurra Apriceno ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Anticancer Agents ◽  
Chemical Properties ◽  
Dark Side ◽  
Stimuli Responsive ◽  
Ag Nps ◽  
Au Nps ◽  
Physico Chemical ◽  
Living Organisms ◽  
Biological Entities

In the last years, there is a growing interest in the application of nanoscaled materials in cancer therapy because of their unique physico-chemical properties. However, the dark side of their usability is limited by their possible toxic behaviour and accumulation in living organisms. Starting from this assumption, the search for a green alternative to produce nanoparticles (NPs) or the discovery of green molecules, is a challenge in order to obtain safe materials. In particular, gold (Au NPs) and silver (Ag NPs) NPs are particularly suitable because of their unique physico-chemical properties, in particular plasmonic behaviour that makes them useful as active anticancer agents. These NPs can be obtained by green approaches, alternative to conventional chemical methods, owing to the use of phytochemicals, carbohydrates, and other biomolecules present in plants, fungi, and bacteria, reducing toxic effects. In addition, we analysed the use of green and stimuli-responsive polymeric bio-inspired nanovesicles, mainly used in drug delivery applications that have revolutionised the way of drugs supply. Finally, we reported the last examples on the use of metallic and Au NPs as self-propelling systems as new concept of nanorobot, which are able to respond and move towards specific physical or chemical stimuli in biological entities.

Stable sample delivery in viscous media via a capillary for serial crystallography

2020 ◽  
Vol 53 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Ki Hyun Nam
Keyword(s):  
Room Temperature ◽  
Capillary Tube ◽  
Glucose Isomerase ◽  
Low Flow ◽  
Innovative Technology ◽  
Delivery Method ◽  
Crystal Sample ◽  
X Ray ◽  
Serial Crystallography ◽  
Delivery Medium

Serial crystallography (SX) is an innovative technology in structural biology that enables the visualization of the molecular dynamics of macromolecules at room temperature. SX experiments always require a considerable amount of effort to deliver a crystal sample to the X-ray interaction point continuously and reliably. Here, a sample-delivery method using a capillary and a delivery medium is introduced. The crystals embedded in the delivery medium can pass through the capillary tube, which is aligned with the X-ray beam, at very low flow rates without requiring elaborate delivery techniques, drastically reducing sample consumption. In serial millisecond crystallography using a viscous medium via a capillary, crystals of lysozyme embedded in agarose, which produce an unstable injection stream at atmospheric pressure, and crystals of glucose isomerase embedded in gelatin, which is known to be problematic for open-extruder operation, were stably delivered at a flow rate of 100 nl min−1. The room-temperature crystal structures of lysozyme and glucose isomerase were successfully determined at 1.85 and 1.70 Å resolutions, respectively. This simple but highly efficient sample-delivery method can allow researchers to deliver crystals precisely to an X-ray beam in SX experiments.

scholarly journals Sample delivery using capillary and delivery medium for serial crystallography

2019 ◽  
Author(s):  
Ki Hyun Nam
Keyword(s):  
Capillary Tube ◽  
Low Flow ◽  
Innovative Technology ◽  
X Rays ◽  
Delivery Method ◽  
Interaction Point ◽  
Crystal Sample ◽  
X Ray ◽  
Serial Crystallography ◽  
Delivery Medium

AbstractSerial crystallography (SX) is an innovative technology in structural biology that enables the visualization of molecular dynamics of macromolecules at room temperature. SX experiments always require a considerable amount of effort to deliver a crystal sample to the X-ray interaction point continuously and reliably. Here, a sample delivery method using a capillary and a delivery medium is introduced. The crystals embedded in the delivery medium can pass through the capillary tube, which is aligned with the X-ray beam, at very low flow rates without requiring elaborate delivery techniques and drastically reducing sample consumption. This simple but highly efficient sample delivery method can allow researchers to deliver crystals precisely to X-rays in SX experiments.

Microfabrication for Packaged Biomolecular Unit Cells

2013 ◽  
Author(s):  
Mary-Anne Nguyen ◽  
Andy Sarles
Keyword(s):  
Self Assembly ◽  
Material System ◽  
Stimuli Responsive ◽  
Critical Feature ◽  
Liquid Phases ◽  
Unit Cells ◽  
Droplet Interface Bilayer ◽  
Polymeric Substrates ◽  
Original Amount

This paper focuses on developing a closed fluidic environment for packaging biomolecular unit cells, which consists of a synthetic lipid bilayer and other biomolecules contained in a near solid-state material with two regions that contain hydrophobic oil (i.e. nonpolar solvent) surrounding aqueous droplets. This research provides a stepping-stone towards an autonomic biomolecular material system, whereby a packaged system will allow for precise droplet interface bilayer (DIB) formation without the interference of outside contamination for long-term applications. Also, substrate materials need to maintain droplets and preserve the self-assembly and stimuli-responsive properties of biomolecules within the unit cell. A critical feature of an encapsulating material is that it does not absorb either of the liquid phases required to form DIBs. Oil depletion tests within sealed, polymeric substrates show that polydimethylsiloxane (PDMS) absorbs full volume of injected hexadecane in approximately 27 hours. However, polyurethane substrates maintain the original amount of oil injected even after several weeks. Bilayer lifetime is also monitored within an environment in which the oil is also depleting. The results of this test show the longevity of a DIB to be shorter than oil lifetime. The lipid-encased droplets disconnect after approximately 10 hours, when there is only approximately <60% amount of oil present. In addition, an initial microfluidic substrate is designed such that a single T-junction intersection can be used to form monodisperse droplets within a primary oil-filled channel and a downstream increase in channel width can be used to connect droplets to form DIBs.

scholarly journals Interfacing a microchip-based capillary electrophoresis system with a microwave induced plasma spectrometry for copper speciation

2011 ◽  
Vol 9 (5) ◽  
pp. 896-903 ◽  
Author(s):  
Henryk Matusiewicz ◽  
Mariusz Ślachciński
Keyword(s):  
Capillary Electrophoresis ◽  
High Efficiency ◽  
Flow Direction ◽  
Low Flow ◽  
Emission Spectrometry ◽  
Aerosol Sample ◽  
Buffer Solution ◽  
Evaporation Chamber ◽  
Microwave Induced Plasma ◽  
Mip Oes

AbstractA microchip-based capillary electrophoresis (µCE) system was interfaced with a microwave induced plasma optical emission spectrometry (MIP-OES) to provide copper species separation capabilities. This system uses an extremely low flow demountable direct injection high efficiency nebulizer (D-DIHEN) sited directly at the liquid exit of the chip. A supplementary flow of buffer solution at the channel exit was used to improve nebulization efficiency. A small evaporation chamber has been incorporated into the interface in order to prevent the losses associated with traditional spray chambers, allowing the entire aerosol sample to enter the plasma. Syringe pumps were used to manipulate the flow rate and flow direction of the sample, buffer, and supplementary buffer solution. Sample volumes of 25 nL can be analyzed. With application of an electric field up to 500 V cm−1, species such as Cu(II) and Cu(EDTA)2− were separated in acidic solution within 90 s using a 26 mm long separation channel etched in a glass base. Resolution of the Cu(II) and Cu(EDTA)2− peaks was 1.1 using the chip-based µCE-MIP-OES system.

scholarly journals Stimuli-Responsive Micelles with Detachable Poly(2-ethyl-2-oxazoline) Shell Based on Amphiphilic Polyurethane for Improved Intracellular Delivery of Doxorubicin

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2642
Author(s):  
Kang Xu ◽  
Xiaojun Liu ◽  
Leran Bu ◽  
Hena Zhang ◽  
Caihong Zhu ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Biomedical Applications ◽  
Fluorescent Microscopy ◽  
Controlled Drug Delivery ◽  
Release Profile ◽  
C6 Cells ◽  
Stimuli Responsive ◽  
Trimethylene Carbonate ◽  
Ph Responsive ◽  
Drug Release Profile

Polyurethanes (PUs) have various biomedical applications including controlled drug delivery. However, the incompletely release of drug at tumor sites limits the efficiency of these drug loaded polyurethane micelles. Here we report a novel polymer poly(2-ethyl-2-oxazoline)-SS-polyurethane-SS-poly(2-ethyl-2-oxazoline) triblock polyurethane (PEtOz-PU(PTMCSS)-PEtOz). The hydrophilic pH-responsive poly(2-ethyl-2-oxazoline) was used as an end-block to introduce pH responsiveness, and the hydrophobic PU middle-block was easily synthesized by the reaction of poly (trimethylene carbonate) diol containing disulfide bonds (PTMC-SS-PTMC diol) and bis (2-isocyanatoethyl) disulfide (CDI). PEtOz-PU(PTMCSS)-PEtOz could self-assemble to form micelles (176 nm). The drug release profile of PEtOz-PU(PTMCSS)-PEtOz micelles loaded with Doxorubicin (DOX) was studied in the presence of acetate buffer (10 mM, pH 5.0) and 10 mM dithiothreitol (DTT). The results showed that under this environment, DOX-loaded polyurethane micelles could release DOX faster and more thoroughly, about 97% of the DOX was released from the DOX-loaded PEtOz-PU(PTMCSS)-PEtOz micelle. In addition, fluorescent microscopy and cell viability assays validated that the DOX-loaded polyurethane micelle strongly inhibits the growth of C6 cells, suggesting their potential as a new nanomedicine against cancer.

scholarly journals SYNTHESIS OF AMINE-CONTAINING POLYMERIC MICROSPHERES BY SEED COPOLYMERIZATION FOR APPLICATIONS IN BIOTECHNOLOGY

2017 ◽  
Vol 12 (4) ◽  
pp. 75-84 ◽  
Author(s):  
A. V. Bakhtina ◽  
A. A. Sivaev ◽  
S. M. Levachev ◽  
S. A. Gusev ◽  
N. A. Lobanova ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Glycidyl Methacrylate ◽  
Capillary Tube ◽  
Chemical Properties ◽  
High Sensitivity ◽  
Latex Agglutination ◽  
Buffer Solution ◽  
Polymeric Microspheres ◽  
Physico Chemical ◽  
Polymer Slurry

This paper presents the results of studies of seed copolymerization of glycidyl methacrylate with ethylene glycol poly(glycidyl methacrylate) on seed particles in order to obtain partially crosslinked polymer microspheres with a diameter of about 3.5 microns for use in immunochemical reactions, as carriers of bioligands. The physico-chemical properties of polymeric microspheres obtained under different conditions were studied by the following methods: the diameters of the particles - by electron scanning and light microscopy; the wetting angle - bу the method of "lying droplets"; the sedimentation velocity - by the macromethod in a capillary tube by the movement of the (polymer slurry)/water phase boundary (buffer solution); the zeta-potential - by dynamic light scattering. Having studied the physical-chemical properties of all polymer slurries we concluded that the optimal particles to create on the basis of their diagnostic test systems with high sensitivity working on the principle of latex agglutination reaction are poly(glycidyl methacrylate) particles with equal percentage of glycidyl methacrylate and ethylene glycol dimethacrylate aminated with hexamethylendiamine in the environment of n-propanol, because they have a sufficient number of amino groups and do not lose their sedimentation properties after all stages of the synthesis.

Observations on single drop formation from a capillary tube at low flow rates

2009 ◽  
Vol 334 (1-3) ◽  
pp. 197-202 ◽  
Author(s):  
Wei Wang ◽  
Kwun Ho Ngan ◽  
Jing Gong ◽  
Panagiota Angeli
Keyword(s):  
Capillary Tube ◽  
Low Flow ◽  
Drop Formation ◽  
Single Drop ◽  
Flow Rates

scholarly journals Multi-stimuli-responsive programmable biomimetic actuator

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yue Dong ◽  
Jie Wang ◽  
Xukui Guo ◽  
Shanshan Yang ◽  
Mehmet Ozgun Ozen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Oxide Film ◽  
Structural Changes ◽  
Single Type ◽  
Small Scale ◽  
Stimuli Responsive ◽  
Living Organisms ◽  
Smart Actuator ◽  
Biomimetic Actuator

Abstract Untethered small actuators have various applications in multiple fields. However, existing small-scale actuators are very limited in their intractability with their surroundings, respond to only a single type of stimulus and are unable to achieve programmable structural changes under different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes. This capability is uniquely achieved by a fast and facile method that was used to fabricate a smart actuator with precise patterning on a graphene oxide film by hydrogel microstamping. The programmable actuator can mimic the claw of a hawk to grab a block, crawl like an inchworm, and twine around and grab the rachis of a flower based on their geometry. Similar to the large- and small-scale robots that are used to study locomotion mechanics, these small-scale actuators can be employed to study movement and biological and living organisms.

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