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Search Publications by: Vytas Reipa (Fed)

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Displaying 1 - 25 of 68

Polyethyleneimine/polyethylene glycol-conjugated gold nanoparticles as nanoscale positive/negative controls in nanotoxicology: Testing in frog embryo teratogenesis assay-Xenopus and mammalian tissue culture system

March 15, 2023
Vytas Reipa, Alessandro Tona, Feng Yi, Bryant C. Nelson, David A. LaVan, Vincent A. Hackley, Tae Joon Cho
Despite the great potential of using positively charged gold nanoparticles (AuNPs) in nanomedicine, no systematic studies have been reported on their synthesis optimization or colloidal stability under physiological conditions until a group at the National

Introduction of nanoscale positive controls for nanotoxicology: A new aspect of utilization of stability-enhanced Gold-Polyethyleneimine conjugates (Au-PEIs)

November 8, 2022
Tae Joon Cho, Vincent A. Hackley, Vytas Reipa, Alessandro Tona, Christopher Sims, Natalia Farkas
Polyethyleneimine (PEI) conjugated gold nanoparticles (Au-PEIs) have potential use as positively charged gold nanoparticles (AuNPs) for nanomedical applications, due to their cationic surface that promotes cellular uptake and gene transfection. We report

Small Angle Neutron Scattering Measurement of Silicon Nanoparticle Size Distribution

October 12, 2021
Jonghoon Choi, Shih-Huang Tung, Nam S. Wang, Vytas Reipa
We have determined the particle size distribution profiles of octane terminated silicon nanoparticle suspensions, produced using the sonication of electrochemically etched Si wafer. Small angle neutron scattering data was analyzed separately in the high (0

Resources for developing reliable and reproducible in vitro test methods

September 29, 2021
Elijah Petersen, Vytas Reipa, Menghang Xia, Monita Sharma
A broad range of in vitro test methods have been developed given their numerous potential advantages over in vivo tests. We describe here key resources and tools to increase the reliability and reproducibility of in vitro test methods.

Preparation, Characterization, and Biological Activity of Stability-Enhanced Polyethyleneimine-Conjugated Gold Nanoparticles (Au-PEI@NIST) for Biological Application

September 16, 2021
Tae Joon Cho, Vincent A. Hackley, Feng Yi, David A. LaVan, Vytas Reipa, Alessandro Tona, Bryant C. Nelson, Christopher Sims, Natalia Farkas
In this special publication, we report on a modified synthetic process that results in a stable suspension of Au-PEI nanoparticles, Au-PEI@NIST. Synthesized materials were characterized using an orthogonal approach that included dynamic light scattering

The Impact and Fate of Graphene Oxide in Graphene Oxide/Polymer Nanocomposites Exposed to Ultraviolet Irradiation

August 11, 2020
David G. Goodwin, Trinny Lai, Yadong Lyu, Chen Yuan Lu, Alejandro Campos, Vytautas Reipa, Tinh Nguyen, Li Piin Sung
Ultraviolet (UV) radiation, heat and moisture can lead to polymer degradation outdoors but the effect of graphene oxide (GO) nanofiller incorporation on this process is unknown. Since GO can improve the mechanical, barrier, and thermal properties of a

Agglomeration of Escherichia coli with positively charged nanoparticles can lead to artifacts in a standard Caenorhabditis elegans toxicity assay

April 19, 2018
Shannon Hanna, Antonio Montoro Bustos, Alexander W. Peterson, Vytas Reipa, Leona D. Scanlan, Sanem Hosbas Coskun, Tae Joon Cho, Monique Johnson, Vincent A. Hackley, Bryant C. Nelson, Michael R. Winchester, John T. Elliott, Elijah Petersen
The increased use and incorporation of engineered nanoparticles (ENPs) in consumer products requires a robust assessment of their potential environmental implications. However, a lack of standardized methods for nanotoxicity testing has yielded results

Acid-induced and pH-controlled Reversible Switching of Broad-Spectrum Antibacterial Activity

February 13, 2018
Yin Y. Nelson, Vytautas Reipa, Xiaohong Wang, Kenneth Mineart, Vivek M. Prabhu, Nancy J. Lin, Jirun Sun
Bacterial resistance to antimicrobials is threatening millions of human lives due to indiscriminate overuse and environmental build-up of antibiotics. We present the smart regulation of antibacterial activity in biologically relevant conditions to reduce

Controlled Potential Electrooxidation of Genomic DNA

January 11, 2018
Vytautas Reipa, Donald H. Atha, Sanem Hosbas Coskun, Christopher M. Sims, Bryant C. Nelson
Exposure of mammalian cells to oxidative stress can result in DNA damage that adversely affects many cell processes. We used bulk electrolysis in an electrochemical system and gas chromatographic mass spectrometric analysis (GC/MS/MS) to control and

Redox-active Nanomaterials for Nanomedicine Applications

October 6, 2017
Christopher Sims, Shannon Hanna, Daniel A. Heller, Christopher Horoszko, Monique Johnson, Antonio Montoro Bustos, Vytas Reipa, Kathryn Riley, Bryant C. Nelson
Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of

The Comet Assay: Methods for Quantitative Image Analysis and Reproducibility

September 1, 2016
Donald H. Atha, Signe Braafladt, Vytautas Reipa
The comet assay,or single cell gel electrophoresis,is a sensitive and efficient technique for analyzing DNA damage in the form of single and double strand breaks in single cells. DNA alteration,from strand breaks,can lead to cancer and other health risks

Quantification of carbon nanotubes in environmental matrices: Current capabilities, case studies, and future improvements

April 6, 2016
Elijah J. Petersen, D. X. Flores-Cervantes, Thomas Bucheli, Lindsay C. Elliott, Jeffrey A. Fagan, Alexander Gogos, Shannon Hanna, Antonio R. Montoro Bustos, Desiree L. Plata, Vytautas Reipa, Paul Westerhoff, Michael R. Winchester, Elisabeth Mansfield
Carbon nanotubes (CNTs) have numerous exciting potential applications approaching commercialization. As such, quantitative measurements of CNTs in key environmental matrices (water, soil, sediment, and biological tissues) are needed to address concerns

The DNA Damaging Potential of Photoactivated P25 Titanium Dioxide Nanoparticles

September 30, 2014
Elijah Petersen, Vytas Reipa, Stephanie S. Watson, Deborah Jacobs, Savelas A. Rabb, Bryant C. Nelson
Titanium dioxide nanoparticles (TiO2 NPs) are found in numerous commercial and personal care products. Thus, it is necessary to understand and characterize their potential environmental health and safety risks. It is well known that photoactivated TiO2 NPs

Probing the intracellular glutathione redox potential using in-cell NMR spectroscopy

January 2, 2014
Steve Y. Rhieu, Aaron A. Urbas, Daniel W. Bearden, John P. Marino, Vytautas Reipa, Katrice A. Lippa
Non-invasive and real-time analysis of cellular redox processes has been greatly hampered by lack of suitable measurement techniques. Here we describe an in-cell nuclear magnetic resonance (NMR)-based method for measuring the intracellular glutathione

Quantitative measurements of glutathione in yeast cell lysate using 1H NMR

February 20, 2013
Steve Y. Rhieu, Aaron A. Urbas, Katrice Lippa, Vytas Reipa
A method for quantifying the level of glutathione (GSH) in yeast cell lysate is described using 1H NMR analysis. For quantification purposes, the 1H resonances corresponding to the Cys βCH2 of GSH were identified as having the fewest overlapping spectral