1Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, 2Department of Chemistry, The Johns Hopkins University
We describe experimental details of the synthesis of patterned and reconfigurable particles from two dimensional (2D) precursors. This methodology can be used to create particles in a variety of shapes including polyhedra and grasping devices at length scales ranging from the micro to centimeter scale.
Published February 4, 2013. Keywords: Chemistry, Chemical Engineering, Biomolecular Engineering, Materials Science, Physics, Nanotechnology, Molecular Self-assembly, Electrochemistry, Folding, three dimensional, lithography, colloid, patchy particles, particles, nanoparticles, robotics, drug delivery, microfabrication, nanofabrication, nano, assembly, synthesis, reaction, origami
1Department of Entomology, Louisiana State University Agricultural Center
We present procedures for demonstrating that ligands bind to the surface membrane of the cellulose-digesting protozoa in the gut of Formosan subterranean termites using fluorescent microscopy and that ligands coupled with lytic peptides kill these protozoa in vitro (anaerobic protozoa culture) and in vivo (injection into the termite hindgut).
Published December 29, 2010. Keywords: Microbiology, Isoptera, Coptotermes formosanus, Formosan subterranean termite, termite control, paratransgenesis, symbionts, anaerobic, fluorescence
1Environmental Microfluidics Group, MIT - Massachusetts Institute of Technology
The fabrication of microfluidic channels and their implementation in experiments for studying the chemotactic foraging behaviour of marine microbes within a patchy nutrient seascape and the swimming behaviour of bacteria within shear flow are described.
Published May 28, 2007. Keywords: Microbiology, issue 4, microbial community, chemotaxis, microfluidics
1Department of Biomedical Engineering, University of Wisconsin – Madison
The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.
Published April 29, 2011. Keywords: Medicine, ex-vivo, mouse, lung, pulmonary vascular impedance, characteristic impedance
1Chemical and Biomolecular Engineering Department, University of Houston
Confocal microscopy is used to image quiescent and flowing colloid-polymer mixtures, which are studied as model systems for attractive suspensions. Image analysis algorithms are used to calculate structural and dynamic metrics for the colloidal particles that measure changes due to geometric confinement.
Published May 20, 2014. Keywords: Chemistry, confocal microscopy, particle tracking, colloids, suspensions, confinement, gelation, microfluidics, image correlation, dynamics, suspension flow
JoVE Applied Physics
1Petroleum & Geosystems Engineering, The University of Texas at Austin
This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.
Published January 3, 2014. Keywords: Physics, chemical engineering, settling velocity, Reynolds number, shear thinning, wall retardation
1Lawrence Berkeley National Laboratory, The Molecular Foundry
More than half of proteins are small proteins (molecular mass <200 kDa) that are challenging for both electron microscope imaging and three-dimensional reconstructions. Optimized negative staining is a robust and high-throughput protocol to obtain high contrast and relatively high resolution (~1 nm) images of small asymmetric proteins or complexes under different physiological conditions.
Published August 15, 2014. Keywords: Environmental Sciences, small and asymmetric protein structure, electron microscopy, optimized negative staining
1Department of Mechanical Engineering, Vanderbilt University
Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.
Published June 15, 2012. Keywords: Bioengineering, Drop-based microfluidics, inertial microfluidics, ordering, focusing, cell encapsulation, single-cell biology, cell signaling
1Barrow Brain Tumor Research Center, Barrow Neurological Institute
We describe the production and characterization of nanoparticles and microparticles composed of poly(lactic-co-glycolic acid) using vitamin E-TPGS as an emulsifier. By varying formulation parameters such as the concentration of emulsifier, it is possible to produce nanoparticles with mean diameters ranging from 220 nm to 1.98 µm.
Published December 27, 2013. Keywords: Chemistry, Nanoparticles, Microparticles, PLGA, TPGS, drug delivery, scanning electron microscopy, emulsion, polymers
JoVE Clinical and Translational Medicine
1Department of Pediatrics, Division of Cardiology, The Children's Hospital of Philadelphia, University of Pennsylvania
These studies report on reversible attachment of adenoviral gene vectors to coatless metal surfaces of stents and model mesh disks. Sustained release of transduction-competent viral particles contingent upon hydrolysis of cross-linkers used for vector immobilization results in a durable site-specific transgene expression in vascular cells and in stented arteries.
Published August 12, 2014. Keywords: Medicine, gene therapy, bioconjugation, adenoviral vectors, stents, local gene delivery, smooth muscle cells, endothelial cells, bioluminescence imaging