Matching Items (7)
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- All Subjects: Electrochemical Impedance Spectroscopy
- All Subjects: Electrical Engineering
Description
Each year, 30,000 patients obtain transplants. To prevent graft rejection, immunosuppressants such as tacrolimus are prescribed. Due to tacrolimus's narrow therapeutic range, a dose that is too low places patients at risk for transplant rejection, but too high of a dose leads to kidney failure. The de facto method for monitoring of transplant patient health is bimonthly blood draws, which are cumbersome, painful, and difficult to translate into urgently needed dosage changes in a timely manner. To improve long-term transplant survival rates, we propose a finger-prick sensor that will provide patients and healthcare providers with a measurement of tacrolimus, immune health (through IL-12), and kidney damage (through cystatin C) levels 100 times more frequently than the status quo. Additionally, patient quality of life will be improved due to reduction in time and pain associated with blood draws. Optimal binding frequencies for each marker were found. However, due to limitations with EIS, the integration of the detection of the three markers into one multimarker sensing platform has not yet been realized. To this end, impedance-time tests were run on each marker along with different antibodies, and optimal times of each marker were determined to be 17s, 6s, and 2s, for tacrolimus, cystatin c, and IL-12, respectively (n=6). The integration of impedance-time analysis with traditional EIS methodologies has the potential to enable multi-marker analysis by analyzing binding kinetics on a single electrode with respect to time. Thus, our results provide unique insight into possibilities to improve and facilitate detection of multiple markers not only for the sensor for solid organ transplant patients, but for the monitoring of patients with disease that also entail the observation of multiple markers. Furthermore, the use of impedance-time testing also provides the ability for another way to optimize accuracy/precision of marker detection because it specifies a particular time, in addition to a particular optimal binding frequency, at which to measure concentration.
ContributorsDoshi, Meera Kshitij (Author) / LaBelle, Jeffrey (Thesis director) / Steidley, Eric (Committee member) / Harrington Bioengineering Program (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
The action/adventure game Grad School: HGH is the final, extended version of a BME Prototyping class project in which the goal was to produce a zombie-themed game that teaches biomedical engineering concepts. The gameplay provides fast paced, exciting, and mildly addicting rooms that the player must battle and survive through, followed by an engineering puzzle that must be solved in order to advance to the next room. The objective of this project was to introduce the core concepts of BME to prospective students, rather than attempt to teach an entire BME curriculum. Based on user testing at various phases in the project, we concluded that the gameplay was engaging enough to keep most users' interest through the educational puzzles, and the potential for expanding this project to reach an even greater audience is vast.
ContributorsNitescu, George (Co-author) / Medawar, Alexandre (Co-author) / Spano, Mark (Thesis director) / LaBelle, Jeffrey (Committee member) / Guiang, Kristoffer (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Improved pancreatic cancer diagnostic technology has the potential to improve patient prognosis by increasing cancer screening rates and encouraging early detection of the cancer. To increase the sensitivity and specificity while decreasing the cost and time investment, the emerging detection method of electrochemical impedance spectroscopy (EIS) was tested to detect two pancreatic cancer specific biomarkers. The antibodies of carcinoembryonic antigen and quiescin sulfhydryl oxidase 1 were immobilized individually to gold disk electrodes and tested for binding to their respective antigens. An AC signal of varying potential and a wide frequency sweep was applied to the electrode system and the resulting imaginary impedance values were analyzed. Based off of the highest slope and R-squared values of the collected impedance values, the optimal binding frequencies of QSOX1 and CEA with their antibodies was determined to be 97.66 Hz and 17.44 Hz, respectively. EIS was also used to test for potential multimarker detection by coimmobilizing anti-CEA and anti-QSOX1 to the surface of gold disk electrodes. Each system's impedance response was correlated to the physiological concentration range of CEA and QSOX1 individually. The resulting impedance and concentration calibration curves had R-squared values of 0.78 and 0.79 for the calculated QSOX1 and CEA, respectively. Both markers showed similar trends between the calculated and actual calibration curves for each marker. The imaginary impedance output lacks two independent peaks for the distinct optimal binding frequencies of both biomarkers after signal subtraction and show a large shift in optimal frequencies. From analyzing the co-immobilization data for the calculated and experimentally determined calibration curves of CEA and QSOX1, both curves had different correlation values between imaginary impedance values and concentration. Add and subtracting the experimental and calculated co-immobilization, QSOX1, and CEA signals suggest an oversaturation of QSOX1 used during the experiments.
ContributorsMalla, Akshara (Co-author) / Murali, Keerthana (Co-author) / LaBelle, Jeffrey (Thesis director) / Lin, Chi-En (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
A point of care glucose sensor using electrochemical impedance spectroscopy (EIS) with a glutaraldehyde-linked enzyme shows promise as an effective biosensor platform. This report details the characterization of various factors on optimal binding frequency (OBF) and sensor performance to better prepare the sensor for future experimentation. Utilizing a screen printed carbon electrode, the necessary amount of glucose oxidase was determined to be 10 mg/mL. Binding time trials ranging from 1-3 minutes demonstrated that 1.5 minutes was the optimal binding time. This timeframe produced the strongest impedance response at each glucose concentration. Using this enzyme concentration and binding time, the native OBF of the biosensor was found to be 1.18 Hz using vector analysis. Temperature testing showed little change in OBF in sensors exposed to 4 \u00B0C through 43.3 \u00B0C. Only exposure to 60 \u00B0C resulted in rapid OBF change which was likely due to glucose oxidase becoming denatured. Humidity tests showed little change in OBF and sensor performance between sensors prepared at the humidities of 7.5%, 10.625% and 16.5% humidity. Alternatively, solutions containing common interference molecules such as uric acid, acetaminophen, and ascorbic acid resulted in a highly shifted OBF and drastically reduced signal.
ContributorsMatloff, Daniel (Co-author) / Khanwalker, Mukund (Co-author) / Johns, Jared (Co-author) / LaBelle, Jeffrey (Thesis director) / Pizziconi, Vincent (Committee member) / Lin, Chi (Committee member) / Dean, W.P. Carey School of Business (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
As of today, there does not exist a cheap diagnostic for lactate for use in trauma centers. $671 billion are spent on trauma accidents and emergency rooms, with money focused on treatments such as YSI and ELISA, costing $1500 and $200, respectively. Gold disk electrodes were used to immobilize lactate dehydrogenase and glucose oxidase, with electrochemical impedance spectroscopy (EIS) used as the method for detection. Two lactate experimental runs were completed with data detailing a linear model and positive correlation for imaginary impedance and concentration, and one glucose experimental run was completed proving that a continuous system can be completed accounting for reaction and consumption using EIS, a process previously not done before.
ContributorsEltohamy, Omar Khaled (Author) / LaBelle, Jeffrey (Thesis director) / Lin, Chi-En (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
This thesis dissertation presents design of portable low power Electrochemical Impedance Spectroscopy (EIS) system which can be used for biomedical applications such as tear diagnosis, blood diagnosis, or any other body-fluid diagnosis. Two design methodologies are explained in this dissertation (a) a discrete component-based portable low-power EIS system and (b) an integrated CMOS-based portable low-power EIS system. Both EIS systems were tested in a laboratory environment and the characterization results are compared. The advantages and disadvantages of the integrated EIS system relative to the discrete component-based EIS system are presented including experimental data. The specifications of both EIS systems are compared with commercially available non-portable EIS workstations. These designed EIS systems are handheld and very low-cost relative to the currently available commercial EIS workstations.
ContributorsGhorband, Vishal (Author) / Blain Christen, Jennifer (Thesis advisor) / Song, Hongjiang (Committee member) / LaBelle, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2016
Description
Over the past fifty years, the development of sensors for biological applications has increased dramatically. This rapid growth can be attributed in part to the reduction in feature size, which the electronics industry has pioneered over the same period. The decrease in feature size has led to the production of microscale sensors that are used for sensing applications, ranging from whole-body monitoring down to molecular sensing. Unfortunately, sensors are often developed without regard to how they will be integrated into biological systems. The complexities of integration are underappreciated. Integration involves more than simply making electrical connections. Interfacing microscale sensors with biological environments requires numerous considerations with respect to the creation of compatible packaging, the management of biological reagents, and the act of combining technologies with different dimensions and material properties. Recent advances in microfluidics, especially the proliferation of soft lithography manufacturing methods, have established the groundwork for creating systems that may solve many of the problems inherent to sensor-fluidic interaction. The adaptation of microelectronics manufacturing methods, such as Complementary Metal-Oxide-Semiconductor (CMOS) and Microelectromechanical Systems (MEMS) processes, allows the creation of a complete biological sensing system with integrated sensors and readout circuits. Combining these technologies is an obstacle to forming complete sensor systems. This dissertation presents new approaches for the design, fabrication, and integration of microscale sensors and microelectronics with microfluidics. The work addresses specific challenges, such as combining commercial manufacturing processes into biological systems and developing microscale sensors in these processes. This work is exemplified through a feedback-controlled microfluidic pH system to demonstrate the integration capabilities of microscale sensors for autonomous microenvironment control.
ContributorsWelch, David (Author) / Blain Christen, Jennifer (Thesis advisor) / Muthuswamy, Jitendran (Committee member) / Frakes, David (Committee member) / LaBelle, Jeffrey (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2012