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Displaying 1 - 20 of 20

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

November 8, 2022
Author(s)
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

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

September 16, 2021
Author(s)
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

Dynamic light scattering distributions by any means

May 21, 2021
Author(s)
Natalia Farkas, John A. Kramar
Dynamic light scattering (DLS) is an essential technique for nanoparticle size analysis and has been employed extensively for decades, but despite its long history and popularity, the choice of weighting and mean of the size distribution often appears to

Interlaboratory comparison of nanoparticle size measurements between NMIJ and NIST using two different types of dynamic light scattering instruments

August 6, 2019
Author(s)
Kayori Takahashi, John A. Kramar, Natalia Farkas, Keiji Takahata, Ichiko Misumi, Kentaro Sugawara, Satoshi Gonda, Kensei Ehara
The question of how to relate particle sizes measured using a fixed-angle dynamic light scattering (DLS) instrument with those measured using a multi-angle DLS instrument is addressed. A series of nearly monodisperse polystyrene latex (PSL) particles with

Validation of Single Particle ICP-MS for Routine Measurements of Nanoparticle Size and Number Size Distribution

November 25, 2018
Author(s)
Antonio R. Montoro Bustos, Premsagar P. Kavuri, Antonio M. Possolo, Natalia Farkas, Andras Vladar, Karen E. Murphy, Michael R. Winchester
Single particle inductively coupled plasma-mass spectrometry (spICP-MS) is an emerging technique capable of measuring nanoparticle size and number concentration simultaneously, of metal-containing nanoparticles (NPs) at environmentally relevant levels

Certification of Standard Reference Material 2365 BK Virus DNA Quantitative Standard

August 29, 2018
Author(s)
Megan H. Cleveland, Natalia Farkas, Kevin M. Kiesler, Blaza Toman, Peter M. Vallone
Standard Reference Material (SRM) 2365 is intended for use in the value assignment of BK virus deoxyribonucleic acid (DNA) to BK DNA controls and standards. A unit of SRM 2365 consists of a well characterized, linearized plasmid, containing BK virus DNA

Certification of Standard Reference Material(R) 2372a Human DNA Quantitation Standard

March 19, 2018
Author(s)
Erica L. Romsos, Margaret C. Kline, Natalia Farkas, David L. Duewer, Blaza Toman
Standard Reference Material (SRM) 2372a is intended for use in the value assignment of human genomic deoxyribonucleic acid (DNA) forensic quantitation materials. A unit of SRM 2372a consists of three well-characterized human genomic DNA materials

Development of the Metrology and Imaging of Cellulose Nanocrystals

September 19, 2011
Author(s)
Michael T. Postek, Andras Vladar, John A. Dagata, Natalia Farkas, Bin Ming, Ryan Wagner, Arvind Raman, Robert J. Moon, Ronald Sabo, Theodore H. Wegner, James Beecher
The development of metrology for nanoparticles is a significant challenge. Cellulose nanocrystals (CNC) are one group of nanoparticles that have high potential economic value but present substantial challenges to the development of the measurement science

Combined scanning probe and light scattering characterization of multi-stage self-assembly of targeted liposome-based delivery systems

December 21, 2010
Author(s)
Natalia Farkas, John A. Dagata, Chengli Yang, Antonina Rait, Kathleen Pirollo, Esther Chang
The mean size and size distribution of a targeted nanoparticle delivery system (NDS) strongly influences the intrinsic stability and functionality of this molecular complex, affects its performance as a systemic drug delivery platform, and ultimately

High-voltage Nanoimprint Lithography of Refractory Metal Film

July 1, 2010
Author(s)
John A. Dagata, Natalia Farkas, R Ramsier
Local oxidation of metal, semiconductor, and polymer surfaces has provided a common basis from which to explore fundamental principles of nanolithography and prototype functional nanostructures for many years now. This article summarizes an investigation

Cellulose Nanocrystals the Next Big Nano-thing?

August 6, 2008
Author(s)
Michael T. Postek, Andras Vladar, John A. Dagata, Natalia Farkas, Bin Ming, Ronald Sabo, Theodore H. Wegner
Biomass surrounds us from the smallest alga to the largest redwood tree. Even the largest trees owe their strength to a newly-appreciated class of nanomaterials known as cellulose nanocrystals (CNC). Cellulose, the world s most abundant natural, renewable

Physical characterization methods for iron-oxide contrast agents encapsulated within a targeted liposome-based delivery system

April 16, 2008
Author(s)
John A. Dagata, Natalia Farkas, Cindi L. Dennis, Robert D. Shull, Vincent A. Hackley, Charles W. Yang, Kathleen F. Pirollo, Esther H. Chang
Intact liposome-based targeted nanoparticle delivery systems (NDS) are immobilized by nonselective binding and characterized by scanning probe microscopy (SPM) in a fluid imaging environment. The size, size distribution, functionality, and stability of an

Nanoscale Oxidation of Zirconium Surfaces: Kinetics and Mechanisms

July 1, 2003
Author(s)
Natalia Farkas, Li Zhang, E A. Evans, R Ramsier, John A. Dagata
We show that AFM-induced oxide features can be reproducibly formed on both Zr and ZrN surfaces, and that the growth rate decreases rapidly with increasing time. There is an increase in oxide-feature height with humidity for both systems, and an