Richard Willson - Academia.edu (original) (raw)

Papers by Richard Willson

Journal of Agricultural and Food Chemistry

Biotechnology and Bioengineering, 2020

The Third Modeling Workshop focusing on bioprocess modeling was held in Kenilworth, NJ in May 201... more The Third Modeling Workshop focusing on bioprocess modeling was held in Kenilworth, NJ in May 2019. A summary of these Workshop proceedings is captured in this manuscript. Modeling is an active area of research within the biotechnology community, and there is a critical need to assess the current state and opportunities for continued investment to realize the full potential of models, including resource and time savings. Beyond individual presentations and topics of novel interest, a substantial portion of the Workshop was devoted toward group discussions of current states and future directions in modeling fields. All scales of modeling, from biophysical models at the molecular level and up through large scale facility and plant modeling, were considered in these discussions and are summarized in the manuscript. Model life cycle management from model development to implementation and sustainment are also considered for different stages of clinical development and commercial producti...

Environmental Science and Pollution Research, Sep 3, 2021

Understanding the transport of sediments in urban estuaries and their effects on water quality an... more Understanding the transport of sediments in urban estuaries and their effects on water quality and microorganisms is a convergent challenge that has yet to be addressed especially as a result of natural hazards that affect the hydrodynamics of estuarine systems. This study provides a holistic view of the longitudinal nature and character of sediment in an urban estuary, the Galveston Bay Estuary System (GBES), under daily and extreme flow regimes and presents the results of water and sediment sampling after Hurricane Harvey. The sediment sampling quantified total suspended sediment (TSS) concentrations, metal concentrations, and the diversity of microbial communities. The results revealed the impact of the substantial sediment loads that were transported into the GBES in terms of sediment grain type, the spatial distribution of trace metals, and the diversity of microbial communities. A measurable shift in the percentage of silt relative to historical norms was noted in the GBES after Hurricane Harvey. Not only did sediment metal data confirms this shift and its ensuing impact on metal concentrations; microbial data provided ample evidence of the effect of leaks and spills from wastewater treatment plants, superfund sites, and industrial runoff on microbial diversity. The research demonstrates the importance of understanding longitudinal sediment transport and deposition in estuarine systems under daily flow regimes but more critically, following natural hazard events to ensure sustainability and resilience of systems such as the GBES that encounter numerous acute and chronic stresses.

Journal of Agricultural and Food Chemistry, Oct 24, 2022

ACS omega, Nov 16, 2017

This paper highlights the relation between the shape of iron oxide (Fe 3 O 4) particles and their... more This paper highlights the relation between the shape of iron oxide (Fe 3 O 4) particles and their magnetic sensing ability. We synthesized Fe 3 O 4 nanocubes and nanospheres having tunable sizes via solvothermal and thermal decomposition synthesis reactions, respectively, to obtain samples in which the volumes and body diagonals/diameters were equivalent. Vibrating sample magnetometry (VSM) data showed that the saturation magnetization (M s) and coercivity of 100−225 nm cubic magnetic nanoparticles (MNPs) were, respectively, 1.4−3.0 and 1.1−8.4 times those of spherical MNPs on a same-volume and same-body diagonal/diameter basis. The Curie temperature for the cubic Fe 3 O 4 MNPs for each size was also higher than that of the corresponding spherical MNPs; furthermore, the cubic Fe 3 O 4 MNPs were more crystalline than the corresponding spherical MNPs. For applications relying on both higher contact area and enhanced magnetic properties, higher-M s Fe 3 O 4 nanocubes offer distinct advantages over Fe 3 O 4 nanospheres of the same-volume or samebody diagonal/diameter. We evaluated the sensing potential of our synthesized MNPs using giant magnetoresistive (GMR) sensing and force-induced remnant magnetization spectroscopy (FIRMS). Preliminary data obtained by GMR sensing confirmed that the nanocubes exhibited a distinct sensitivity advantage over the nanospheres. Similarly, FIRMS data showed that when subjected to the same force at the same initial concentration, a greater number of nanocubes remained bound to the sensor surface because of higher surface contact area. Because greater binding and higher M s translate to stronger signal and better analytical sensitivity, nanocubes are an attractive alternative to nanospheres in sensing applications.

Nanoscale, 2014

Please note that technical editing may introduce minor changes to the text and/or graphics, which... more Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal's standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains.

The COVID-19 pandemic has highlighted the urgent need for sensitive, affordable, and widely-acces... more The COVID-19 pandemic has highlighted the urgent need for sensitive, affordable, and widely-accessible testing at the point-of-care. Here we report the development of a sensitive chemiluminescence-based smartphone-readable lateral flow assay for the detection of SARS-CoV-2 nucleoprotein using M13 phage conjugated with antibodies and HRP enzymes as LFA reporter particles. We screened 84 anti-nucleoprotein monoclonal antibody pairs in phage LFA and identified an antibody pair that gave an LoD of 25 pg/mL nucleoprotein in nasal swab extract using a FluorChem gel documentation system and 100 pg/mL when the test was imaged and analyzed by an in-house-developed smartphone reader. The smartphone-read LFA signals for positive clinical samples tested (N = 15, with known Ct) were statistically different (p < 0.001) from negative clinical samples tested (N = 11). The translation-ready phage LFA technology combined with smartphone chemiluminescence imaging can enable the timely development o...

Marine Pollution Bulletin, 2022

Estuaries experience variable physicochemical conditions, especially after hurricanes and due to ... more Estuaries experience variable physicochemical conditions, especially after hurricanes and due to anthropogenic sources of pollution. Their microbial communities are not as well understood in terms of community structure and diversity, particularly in response to stresses from pollution and severe events. This study presents a 16S rRNA-based description of sediment microbial communities in the Houston Ship Channel-Galveston Bay estuary after Hurricane Harvey in 2017. A total of 11 sites were sampled, and microbial genomic DNA was isolated from sediment. The presence and abundance of specific bacterial and archaeal taxa in the sediment indicated pollutant inputs from identified legacy sources. The abundance of certain microbial groups was explained by the mobilization of contaminated sediment and sediment transport due to Harvey. Several microorganisms involved in the biodegradation of xenobiotics were observed. The spatial occurrence of Dehalococcoidia, a degrader of persistent polychlorinated compounds, was explained in relation to sediment properties and contaminant concentrations.

Investigative Ophthalmology & Visual Science, 2009

Biosensors and Bioelectronics, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Frontiers in Cellular and Infection Microbiology, 2019

Analytical Methods, 2020

Multicolor multiplex lateral flow assay using persistent luminescent nanophosphors as reporters.

ACS omega, Jan 30, 2017

This paper highlights the relation between the shape of iron oxide (Fe3O4) particles and their ma... more This paper highlights the relation between the shape of iron oxide (Fe3O4) particles and their magnetic sensing ability. We synthesized Fe3O4 nanocubes and nanospheres having tunable sizes via solvothermal and thermal decomposition synthesis reactions, respectively, to obtain samples in which the volumes and body diagonals/diameters were equivalent. Vibrating sample magnetometry (VSM) data showed that the saturation magnetization (Ms) and coercivity of 100-225 nm cubic magnetic nanoparticles (MNPs) were, respectively, 1.4-3.0 and 1.1-8.4 times those of spherical MNPs on a same-volume and same-body diagonal/diameter basis. The Curie temperature for the cubic Fe3O4 MNPs for each size was also higher than that of the corresponding spherical MNPs; furthermore, the cubic Fe3O4 MNPs were more crystalline than the corresponding spherical MNPs. For applications relying on both higher contact area and enhanced magnetic properties, higher-Ms Fe3O4 nanocubes offer distinct advantages over Fe3O...

Sensors (Basel, Switzerland), Jan 6, 2017

Ta/Ru/Co/Ru/Co/Cu/Co/Ni80Fe20/Ta spin-valve giant magnetoresistive (GMR) multilayers were deposit... more Ta/Ru/Co/Ru/Co/Cu/Co/Ni80Fe20/Ta spin-valve giant magnetoresistive (GMR) multilayers were deposited using UHV magnetron sputtering and optimized to achieve a 13% GMR ratio before patterning. The GMR multilayer was patterned into 12 sensor arrays using a combination of e-beam and optical lithographies. Arrays were constructed with 400 nm × 400 nm and 400 nm × 200 nm sensors for the detection of reporter nanoparticles. Nanoparticle detection was based on measuring the shift in high-to-low resistance switching field of the GMR sensors in the presence of magnetic particle(s). Due to shape anisotropy and the corresponding demag field, the resistance state switching fields were significantly larger and the switching field distribution significantly broader in the 400 nm × 200 nm sensors as compared to the 400 nm × 400 nm sensors. Thus, sensor arrays with 400 nm × 400 nm dimensions were used for the demonstration of particle detection. Detection of a single 225 nm Fe₃O₄ magnetic nanopartic...

ACS applied materials & interfaces, 2017

To identify factors controlling the performance of reporter particles in a sensitive lateral-flow... more To identify factors controlling the performance of reporter particles in a sensitive lateral-flow assay (LFA), we investigated the effect of the flux and shape of filamentous bacteriophage (phage) on the performance of phage LFAs. Phage of three different lengths and diameters were modified with biotin and AlexaFluor 555 as binding and read-out elements, respectively. The binding efficiencies of the functionalized phage were tested in a fibrous glass LFA membrane modified with avidin. The total binding rate, quantified using real-time particle counting and particle image velocimetry, decreased monotonically with the average bulk flux of phage through the membrane. At the pore scale, more phage bound in regions with faster local flow, confirming that both average and local flux increased binding. The number of bound phage increased with the aspect ratio of the phage and scaled with the phage surface area, consistent with a binding interaction controlled by the number of recognition e...

The Analyst, 2016

Magnetic sensing utilizes loss of signal via enzymatic transformation of magnetic nanoparticles (... more Magnetic sensing utilizes loss of signal via enzymatic transformation of magnetic nanoparticles (MNPs).