Two-phase systems in which one is uniformly dispersed in another as particles small enough so they cannot be filtered or will not settle out. The dispersing or continuous phase or medium envelops the particles of the discontinuous phase. All three states of matter can form colloids among each other.
1Department of Chemistry, Wright State University, 2Department of Neuroscience, Cell Biology, and Physiology, Wright State University
Tangential flow ultrafiltration (TFU) is a recirculation method used for the weight-based separation of biosamples. TFU was adapted to size-select (1-20 nm diameter) and highly concentrate a large volume of polydisperse silver nanoparticles (4 L of 15.2 μg ml-1 down to 4 ml of 8,539.9 μg ml-1) with minimal aggregation.
Published October 4, 2012. Keywords: Chemistry, Biomedical Engineering, Chemical Engineering, Nanotechnology, silver nanoparticles, size selection, concentration, tangential flow ultrafiltration
1Department of Physics and Astronomy, The University of Texas at San Antonio, 2Centro de Investigaciones en Optica A. C., 3Department of Biology and Neurosciences Institute, The University of Texas at San Antonio
We synthesized star shaped gold nanostars using a silver seed mediated growth method. The diameter of the nanostars ranges from 200 to 300 nm and the number of tips vary from 7 to 10. The nanoparticles have a broad surface plasmon resonance mode centered in the near infrared.
Published January 15, 2012. Keywords: Bioengineering, thermal ablation, surface plasmon resonance, nanoparticle, nanotechnology, silver seeds
1Oak Ridge Institute for Science and Education, 2Air Force Research Laboratory, Airbase Technology Division, 3School of Materials Science and Engineering, Clemson University
Silica nanoparticles were prepared using acid-catalysis of a siloxane precursor and microwave-assisted synthetic techniques resulting in the controlled growth of nanomaterials ranging from 30-250 nm in diameter. The growth dynamics can be controlled by varying the initial silicic acid concentration, time of the reaction, and temperature of reaction.
Published December 16, 2013. Keywords: Chemistry, Chemistry, chemical manufacturing, chemistry (general), materials (general), nanocomposites, catalysts (chemical), chemistry of compounds, Chemistry and Materials (General), Composite Materials, Inorganic, Organic and Physical Chemistry, Engineering (General), Microwave, nanoparticle, silica, silicic acid, NP, SiO2, synthesis
JoVE Immunology and Infection
1Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 2Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, 3Department of Microbiology and Immunology, SUNY Upstate Medical University, 4Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center
The phagokinetic motility track assay is a method used to assess the movement of cells. Specifically, the assay measures chemokinesis (random cell motility) over time in a quantitative manner. The assay takes advantage of the ability of cells to create a measurable track of their movement on colloidal gold-coated coverslips.
Published December 4, 2012. Keywords: Immunology, Microbiology, Cellular Biology, Molecular Biology, gold nanoparticles, coverslips, cell migration, quantitative cell movement, microscopy, motility, assay
JoVE Clinical and Translational Medicine
1Department of Surgical Oncology, University of Texas M.D. Anderson Cancer Center, 2Department of Chemistry, Rice University, 3Mechanical Engineering and Materials Science, Rice University
We describe the protocols used to investigate the interactions of 13.56 MHz radiofrequency (RF) electric-fields with gold nanoparticle colloids in both non-biological and biological systems (in vitro/vivo). These interactions are being investigated for applications in cancer therapy.
Published August 28, 2013. Keywords: Medicine, Electronics and Electrical Engineering, Life Sciences (General), Radiofrequency, Cancer, Nanoparticles, Hyperthermia, Gold
JoVE Immunology and Infection
1Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 2The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, 3National Library of Medicine, National Institutes of Health, 4Massachusetts Institute of Technology, 5William Fremd High School, 6University of Virginia, 7Duke University, 8Yale University, 9University of Notre Dame, 10Washington University in St. Louis, 11Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12Thomas Jefferson High School for Science and Technology
The protocol describes a high-throughput approach to determining structures of membrane proteins using cryo-electron tomography and 3D image processing. It covers the details of specimen preparation, data collection, data processing and interpretation, and concludes with the production of a representative target for the approach, the HIV-1 Envelope glycoprotein. These computational procedures are designed in a way that enables researchers and students to work remotely and contribute to data processing and structural analysis.
Published December 1, 2011. Keywords: Immunology, HIV, Envelope glycoprotein, membrane protein, vaccine design, cryo-electron tomography, transmission electron microscopy, structural biology, high school science, scientific outreach, scientific visualization, National Institutes of Health, National Cancer Institute, National Library of Medicine
1Department of Biomedical Engineering, The University of Akron, 2Saint Vincent Saint Mary's High School
This work describes the formation of poly(ethylene glycol) (PEG) microgels via a photopolymerized precipitation reaction. Increasing the PEG molecular weight increased microgel diameter and swelling ratio. Simple adaptations to the PEG microgel precipitation reaction are explored for future applications of microgels as drug delivery vehicles and tissue engineering scaffolds.
Published December 23, 2013. Keywords: Bioengineering, hydrogels, microgels, polyethylene glycol, molecuar weight, photopolymerized precipitation reaction, polymers, polydispersity index
JoVE Applied Physics
1Institute of Chemistry, The Hebrew University of Jerusalem, 2Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem
A detailed procedure for surface doping of Silicon interfaces is provided. The ultra-shallow surface doping is demonstrated by using phosphorus containing monolayers and rapid annealing process. The method can be used for doping of macroscopic area surfaces as well as nanostructures.
Published December 2, 2013. Keywords: Basic Protocol, nanotechnology, chemistry, monolayer contact doping (MLCD), nanowire, silicon substrate, chemical vapor deposition (CVD),
1Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, 2Department of Biochemistry and Molecular Biology, Gottwald Center for the Sciences, University of Richmond
Alkanethiolate stabilized gold colloids known as monolayer protected clusters (MPCs) are synthesized, characterized, and assembled into thin films as an adsorption interface for protein monolayer electrochemistry of simple redox protein like Pseudomonas aeruginosa azurin (AZ) and cytochrome c (cyt c).
Published October 4, 2011. Keywords: Bioengineering, Monolayer protected clusters, film assemblies, protein monolayer electrochemistry, azurin, self-assembled monolayers
JoVE Immunology and Infection
1Plant Sciences Institute, Agricultural Research Service, United States Department of Agriculture, 2Molecular Plant Pathology Laboratory, Agricultural Research Service, United States Department of Agriculture
A method to analyze the solvent accessibility of the thiol group of cysteine residues of Maize rayado fino virus (MRFV)-virus-like particles (VLPs) followed by a peptide cross-linking reaction is described. The method takes advantage of the availability of several chemical groups on the surface of the VLPs that can be targets for specific reactions.
Published February 14, 2013. Keywords: Virology, Plant Biology, Infection, Molecular Biology, Biochemistry, Proteins, Chemicals and Drugs, Analytical, Diagnostic and Therapeutic Techniques and Equipment, Technology, Industry, Agriculture, Chemistry and materials, Virus-like particles (VLPs), VLP, sulfhydryl-reactive chemistries, labeling, cross-linking, multivalent display, Maize rayado fino virus, mosaic virus, virus, nanoparticle, drug delivery, peptides, Nicotiana benthamiana, plant model