Adaptable Xerogel-Layered Amperometric Biosensor Platforms on Wire Electrodes for Clinically Relevant Measurements

Biosensing strategies that employ readily adaptable materials for different analytes, can be miniaturized into needle electrode form, and function in bodily fluids represent a significant step toward the development of clinically relevant in vitro and in vivo sensors. In this work, a general scheme for 1st generation amperometric biosensors involving layer-by-layer electrode modification with enzyme-doped xerogels, electrochemically-deposited polymer, and polyurethane semi-permeable membranes is shown to achieve these goals. With minor modifications to these materials, sensors representing potential point-of-care medical tools are demonstrated to be sensitive and selective for a number of conditions. The potential for bedside measurements or continuous monitoring of analytes may offer faster and more accurate clinical diagnoses for diseases such as diabetes (glucose), preeclampsia (uric acid), galactosemia (galactose), xanthinuria (xanthine), and sepsis (lactate). For the specific diagnostic application, the sensing schemes have been miniaturized to wire electrodes and/or demonstrated as functional in synthetic urine or blood serum. Signal enhancement through the incorporation of platinum nanoparticle film in the scheme offers additional design control within the sensing scheme. The presented sensing strategy has the potential to be applied to any disease that has a related biomolecule and corresponding oxidase enzyme and represents rare, adaptable, sensing capabilities

Functionalized Carbon Nanotube Adsorption Interfaces for Electron Transfer Studies of Galactose Oxidase

Modified electrodes featuring specific adsorption platforms able to access the electrochemistry of the copper containing enzyme galactose oxidase (GaOx) were explored, including interfaces featuring nanomaterials such as nanoparticles and carbon nanotubes (CNTs). Electrodes modified with various self-assembled monolayers (SAMs) including those with attached nanoparticles or amide-coupled functionalized CNTs were examined for their ability to effectively immobilize GaOx and study the redox activity related to its copper core. While stable GaOx electrochemistry has been notoriously difficult to achieve at modified electrodes, strategically designed functionalized CNT-based interfaces, cysteamine SAM-modified electrode subsequently amide-coupled to carboxylic acid functionalized single wall CNTs, were significantly more effective with high GaOx surface adsorption along with well-defined, more reversible, stable (≥ 8 days) voltammetry and an average ET rate constant of 0.74 s-1 in spite of increased ET distance - a result attributed to effective electronic coupling at the GaOx active site. Both amperometric and fluorescence assay results suggest embedded GaOx remains active. Fundamental ET properties of GaOx may be relevant to biosensor development targeting galactosemia while the use functionalized CNT platforms for adsorption/electrochemistry of electroactive enzymes/proteins may present an approach for fundamental protein electrochemistry and their future use in both direct and indirect biosensor schemes

Hydrodynamic Analysis of a Wave Energy Converter (WEC)

Honorable Mention Winner The UNF CREW competing in the U.S. Department of Energy 2021 Marine Energy Collegiate Competition developed a Wave Energy Converter (WEC) for quick deployment in disaster relief areas. When natural disasters disable coastal power grids, a WEC can be easily deployed close to shore and serve as a source of electricity. The ocean waves move magnets through a coil wired within the WEC to generate electricity. To initiate the design process, ANSYS AQWA software simulated both the oceanic environment and the device’s response in the WEC’s testing conditions. AQWA allows the user to change device dimensions easily and optimize the design ahead of physical construction. The resulting WEC proof of concept minimized prototype manufacturing waste and cost by eliminating poor designs in advance. The simulated geometry neglected hollow sections and used unidirectional, regular waves to account for software limitations. The software simulated the WEC for 20 seconds in an oceanic environment with a 40-meter depth and a 0.25-meter amplitude regular wave. Simulations produced graphs and animations describing the forces acting on the WEC as well as the WEC’s movement. The animation proved that the WEC reacts well in similar physical testing conditions. Based on the simulation results, the team constructed a 3D model for small-scale testing. Future investigations will involve more complex designs. Research conducted onward will focus on mass-damper systems and contact surfaces provided in the software

Cost Analysis of Osprey C.R.E.W.

Renewable energy adoption is on the rise in the U.S. and abroad. More than ever, energy sourcing needs to shift away from harmful fossil fuels and towards fully renewable energy sources. Adapting from traditional fossil fuel energy sources to renewable energy sources is paramount for environmental health and public health. Fossil fuels emit harmful pollutants, which have led to changing weather conditions and exasperated natural disasters. Existing renewable sources are not ideal, either. For instance, solar cannot run continuously and wind turbines are subject to weather changes. The recent energy debacle in Texas shows the need for alternative renewable energy sources. The Osprey C.R.E.W. wave energy converter (WEC) alleviates many of the current problems existing renewable energy systems cannot solve. First, it provides reliable and constant service. With other renewable energy services, there will be stops in production. However, there are no stops in wave energy because the waves are constant. Another positive of the WEC device is that their deployments are flexible and scalable. This means that energy production levels can be changed rapidly and without delay. The average cost per device falls significantly with seamless scalability, making large increments of devices procured in a relatively cost-effective manner. Cost comparisons between competing energy sources show that the WEC is very cost-efficient as well. The cost of producing wave energy is found to be more efficient than solar energy and wind alternatives. Our cost figures also show that Osprey C.R.E.W provides a very competitive alternative to the primary fossil fuel producers such as coal and fuel

Optimization of Power Performance of a Wave Energy Converter

With climate change on the rise, unprecedented dependence on electricity, and an increased incidence of extreme weather, the UNF team participating in the U.S. Department of Energy 2021 Marine Energy Collegiate Competition: Powering the Blue Economy wants to give an alternative solution to provide renewable energy in areas that lose electricity as a result of a natural disaster, or that due to their isolated location cannot use traditional renewable energy sources. This led to the creation of the Osprey C.R.E.W (Cheap Reliable Energy from Waves). The Osprey C.R.E.W. is a wave energy converter that uses the vertical motion of the ocean waves to generate electricity. The principle of energy conversion is Faraday’s Law of Electromagnetic Induction, which states that a magnetic field moving past a conductor will generate electricity. The UNF team has developed a numerical simulation to test how different parameters influence the output and has built three small-scale prototypes that have been tested in a wave tank. A medium-sized prototype and a wave pool are being constructed, with the expectation that the size will also increase the output

First Generation Amperometric Biosensing of Galactose with Xerogel-Carbon Nanotube Layer-By-Layer Assemblies

A first-generation amperometric galactose biosensor has been systematically developed utilizing layer-by-layer (LbL) construction of xerogels, polymers, and carbon nanotubes toward a greater fundamental understanding of sensor design with these materials and the potential development of a more efficient galactosemia diagnostic tool for clinical application. The effect of several parameters (xerogel silane precursor, buffer pH, enzyme concentration, drying time and the inclusion of a polyurethane (PU) outer layer) on galactose sensitivity were investigated with the critical nature of xerogel selection being demonstrated. Xerogels formed from silanes with medium, aliphatic side chains were shown to exhibit significant enhancements in sensitivity with the addition of PU due to decreased enzyme leaching. Semi-permeable membranes of diaminobenzene and resorcinol copolymer and Nafion were used for selective discrimination against interferent species and the accompanying loss of sensitivity with adding layers was countered using functionalized, single-walled carbon nanotubes (CNTs). Optimized sensor performance included effective galactose sensitivity (0.037 μA/mM) across a useful diagnostic concentration range (0.5 mM to 7 mM), fast response time (~30 s), and low limits of detection (~80 μM) comparable to literature reports on galactose sensors. Additional modification with anionic polymer layers and/or nanoparticles allowed for galactose detection in blood serum samples and additional selectivity effectiveness

The Physical Activity and Alzheimer's disease (PAAD) study: Cognitive outcomes

Background: Alzheimer’s disease is a progressive disease that degrades cognitive functioning and ultimately results in death. Currently, there is no cure for Alzheimer’s disease and, hence, the identification of preventative strategies is important. Physical activity (PA) is a behavioral intervention that holds promise with respect to delaying the onset of Alzheimer’s disease. Purpose: The purpose of this study was to explore the differential cognitive benefits achieved in response to PA as a function of a person’s genetic risk for AD. Methods: Older cognitively normal adults (50–65 years) with a family history of AD (FHxAD) participated in an 8-month PA program. Cognitive performance was measured at baseline, pretest, midtest, and posttest and changes over time were assessed as a function of apolipoprotein E (APOE) status (carriers: 1–2 copies of the ?4 allele; noncarriers: 0 copies of the ?4 allele). Results: Improvements in memory were associated with PA participation irrespective of APOE ?4 carrier status. Conclusions: Future experimental studies are needed to confirm that PA causes improvements to cognitive performance in older cognitively normal adults with a FHxAD and that these improvements are equivalent for cognitively normal APOE ?4 carriers and noncarriers

Heat capacity and thermodynamic properties of ditungsten carbide, W2C1-x, from 10 to 1000 K

Thermodynamic properties of tungsten carbide, W2C0.833, have been derived from heat capacities measured by adiabatic calorimetry in the range 10-1000 K on a sample rich in this phase. The standard entropy of W2C0.833 was found to be 75.80 J K-1 mol-1 at 298.15 K and 159.8 J K-1 mol-1 at 1000 K. Thermodynamic formation values for W2C0.833 were deduced from the reported coexistence of this phase with tungsten and tungsten monocarbide at about 1550 K.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27259/1/0000268.pd