arXiv subjects

Alexis Scholtz

Publications and source records attributed to Alexis Scholtz.

4 recordsLinked to original sources

arXiv2024

Synthesis and Characterization of Superparamagnetic Iron Oxide Nanoparticles: A Series of Laboratory Experiments

The following laboratory procedure provides students with a hands-on experience in nanomaterials chemistry and characterization. This three-day protocol is easy to follow for undergraduates with basic chemistry or materials science backgrounds and is suitable for inclusion in upper division courses in inorganic chemistry or materials science. Students use air-free chemistry procedures to synthesize and separate iron oxide magnetic nanoparticles and subsequently modify the nanoparticle surface using a chemical stripping agent. The morphology and chemical composition of the nanoparticles are characterized using electron microscopy and dynamic light scattering measurements. Additionally, magnetic characterization of the particles is performed using an open-source (3D-printed), inexpensive magnetophotometer. Possible modifications to the synthesis procedure including the incorporation of dopants to modify the magnetic response and alternative characterization techniques are discussed. The three-day synthesis, purification, and characterization laboratory will prepare students with crucial skills for advanced technology industries such as semiconductor manufacturing, nanomedicine, and green chemistry.

physics.ed-ph↗

arXiv2023

Open-Source Benchtop Magnetophotometer (MAP) for Characterizing the Magnetic Susceptibility of Suspended Nanoparticles

Magnetic nanoparticles (MNPs) form the foundation of many technologies, frequently serving to purify proteins or cells from a biological sample or to remove environmental contaminants. Their success relies on their magnetic response, which allows them to be easily controlled in a liquid or solution. Therefore, the magnetic susceptibility provides one metric for assessing the suitability of a MNP for a given application. Unfortunately, conventional methods for measuring the magnetic susceptibility relies on instrumentation that characterizes the MNPs as a dry powder. Because MNPs are typically used in suspension, the measured value may be different from their behavior in suspension, thus providing inaccurate readings. Here, we present the design and validation of a magnetophotometer (MAP), an instrument that characterizes the effective magnetic susceptibility of suspended MNPs via differential optical spectroscopy, providing a more relevant measure of MNPs' magnetic properties. As part of this work, we developed a mathematical model to calculate the effective magnetic susceptibility from the MAP data and validated the model using control measurements with iron oxide nanoparticles. Finally, we demonstrate that MAP testing is non-destructive by successfully characterizing bioconjugated particles without damaging the bioactivity of the surface bioconjugation, providing a path for in-line quality control assessment.

physics.ins-det↗

arXiv2021

COVID-19 Diagnostics: Past, Present, and Future

In winter of 2020, SARS-CoV-2 emerged as a global threat, impacting not only health but also financial and political stability. To address the societal need for monitoring the spread of SARS-CoV-2, many existing diagnostic technologies were quickly adapted to detect SARS-CoV-2 RNA and antigens as well as the immune response and new testing strategies were developed to accelerate time-to-decision. In parallel, the infusion of research support accelerated the development of new spectroscopic methods. While these methods have significantly reduced the impact of SARS-CoV-2 on society when coupled with behavioral changes, they also lay the groundwork for a new generation of platform technologies. With several epidemics on the horizon, such as the rise of antibiotic-resistant bacteria, the ability to quickly pivot the target pathogen of this diagnostic toolset will continue to have an impact.

physics.med-ph↗

arXiv2020

Low-tech solutions for the COVID19 supply chain crisis

A global effort is ongoing in the scientific community and in the Maker Movement, which focuses on creating devices and tinkering with them, to reverse engineer commercial medical equipment and get it to healthcare workers. For these low-tech solutions to have a real impact, it is important for them to coalesce around approved designs.

physics.soc-ph↗