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- All Subjects: Biomedical Engineering
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Description
Colorimetric assays are an important tool in point-of-care testing that offers several advantages to traditional testing methods such as rapid response times and inexpensive costs. A factor that currently limits the portability and accessibility of these assays are methods that can objectively determine the results of these assays. Current solutions consist of creating a test reader that standardizes the conditions the strip is under before being measured in some way. However, this increases the cost and decreases the portability of these assays. The focus of this study is to create a machine learning algorithm that can objectively determine results of colorimetric assays under varying conditions. To ensure the flexibility of a model to several types of colorimetric assays, three models were trained on the same convolutional neural network with different datasets. The images these models are trained on consist of positive and negative images of ETG, fentanyl, and HPV Antibodies test strips taken under different lighting and background conditions. A fourth model is trained on an image set composed of all three strip types. The results from these models show it is able to predict positive and negative results to a high level of accuracy.
ContributorsFisher, Rachel (Author) / Blain Christen, Jennifer (Thesis director) / Anderson, Karen (Committee member) / School of Life Sciences (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
The past two decades have been monumental in the advancement of microchips designed for a diverse range of medical applications and bio-analysis. Owing to the remarkable progress in micro-fabrication technology, complex chemical and electro-mechanical features can now be integrated into chip-scale devices for use in biosensing and physiological measurements. Some of these devices have made enormous contributions in the study of complex biochemical processes occurring at the molecular and cellular levels while others overcame the challenges of replicating various functions of human organs as implant systems. This thesis presents test data and analysis of two such systems. First, an ISFET based pH sensor is characterized for its performance in a continuous pH monitoring application. Many of the basic properties of ISFETs including I-V characteristics, pH sensitivity and more importantly, its long term drift behavior have been investigated. A new theory based on frequent switching of electric field across the gate oxide to decrease the rate of current drift has been successfully implemented with the help of an automated data acquisition and switching system. The system was further tested for a range of duty cycles in order to accurately determine the minimum length of time required to fully reset the drift. Second, a microfluidic based vestibular implant system was tested for its underlying characteristics as a light sensor. A computer controlled tilt platform was then implemented to further test its sensitivity to inclinations and thus it‟s more important role as a tilt sensor. The sensor operates through means of optoelectronics and relies on the signals generated from photodiode arrays as a result of light being incident on them. ISFET results show a significant drop in the overall drift and good linear characteristics. The drift was seen to reset at less than an hour. The photodiodes show ideal I-V comparison between photoconductive and photovoltaic modes of operation with maximum responsivity at 400nm and a shunt resistance of 394 MΩ. Additionally, post-processing of the tilt sensor to incorporate the sensing fluids is outlined. Based on several test and fabrication results, a possible method of sealing the open cavity of the chip using a UV curable epoxy has been discussed.
ContributorsMamun, Samiha (Author) / Christen, Jennifer Blain (Thesis advisor) / Goryll, Michael (Committee member) / Yu, Hongyu (Committee member) / Arizona State University (Publisher)
Created2011
Description
Continuous monitoring in the adequate temporal and spatial scale is necessary for a better understanding of environmental variations. But field deployments of molecular biological analysis platforms in that scale are currently hindered because of issues with power, throughput and automation. Currently, such analysis is performed by the collection of large sample volumes from over a wide area and transporting them to laboratory testing facilities, which fail to provide any real-time information. This dissertation evaluates the systems currently utilized for in-situ field analyses and the issues hampering the successful deployment of such bioanalytial instruments for environmental applications. The design and development of high throughput, low power, and autonomous Polymerase Chain Reaction (PCR) instruments, amenable for portable field operations capable of providing quantitative results is presented here as part of this dissertation. A number of novel innovations have been reported here as part of this work in microfluidic design, PCR thermocycler design, optical design and systems integration. Emulsion microfluidics in conjunction with fluorinated oils and Teflon tubing have been used for the fluidic module that reduces cross-contamination eliminating the need for disposable components or constant cleaning. A cylindrical heater has been designed with the tubing wrapped around fixed temperature zones enabling continuous operation. Fluorescence excitation and detection have been achieved by using a light emitting diode (LED) as the excitation source and a photomultiplier tube (PMT) as the detector. Real-time quantitative PCR results were obtained by using multi-channel fluorescence excitation and detection using LED, optical fibers and a 64-channel multi-anode PMT for measuring continuous real-time fluorescence. The instrument was evaluated by comparing the results obtained with those obtained from a commercial instrument and found to be comparable. To further improve the design and enhance its field portability, this dissertation also presents a framework for the instrumentation necessary for a portable digital PCR platform to achieve higher throughputs with lower power. Both systems were designed such that it can easily couple with any upstream platform capable of providing nucleic acid for analysis using standard fluidic connections. Consequently, these instruments can be used not only in environmental applications, but portable diagnostics applications as well.
ContributorsRay, Tathagata (Author) / Youngbull, Cody (Thesis advisor) / Goryll, Michael (Thesis advisor) / Blain Christen, Jennifer (Committee member) / Yu, Hongyu (Committee member) / Arizona State University (Publisher)
Created2013
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
Description
This research investigated using impedance as a minimally invasive oral cancer-screening tool by modeling healthy and diseased tissue. This research developed an ultra-structurally based tissue model for oral mucosa that is versatile enough to be easily modified to mimic the passive electrical impedance responses of multiple benign and cancerous tissue types. This new model provides answers to biologically meaningful questions related to the impedance response of healthy and diseased tissues. This model breaks away from the old empirical top down "black box" Thèvinin equivalent model. The new tissue model developed here was created from a bottom up perspective resulting in a model that is analogous to having a "Transparent Box" where each network element relating to a specific structural component is known. This new model was developed starting with sub cellular ultra-structural components such as membranes, proteins and electrolytes. These components formed the basic network elements and topology of the organelles. The organelle networks combine to form the cell networks. The cell networks combine to make networks of cell layers and the cell layers were combined into tissue networks. This produced the complete "Transparent Box" model for normal tissue. This normal tissue model was modified for disease based on the ultra-structural pathology of each disease. The diseased tissues evaluated include cancers type one through type three; necrotic-inflammation, hyperkeratosis and the compound condition of hyperkeratosis over cancer type two. The impedance responses for each of the disease were compared side by side with the response of normal healthy tissue. Comparative evidence from the models showed the structural changes in cancer produce a unique identifiable impedance "finger print." The evaluation of the "Transparent Box" model for normal tissues and diseased tissues show clear support for using comparative impedance measurements as a clinical tool for oral cancer screening.
ContributorsPelletier, Peter Robert (Author) / Kozicki, Michael (Thesis advisor) / Towe, Bruce (Committee member) / Saraniti, Marco (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2012
Description
This research investigates the whether dietary and nutritional treatments will improve some of the symptoms of autism. This treatment includes a combination of 6 nutritional and dietary treatments, which are vitamins/minerals, essential fatty acids, Epsom salts, carnitine, digestive enzymes, and healthy gluten-free, casein-free diet. 55 participants were involved in this study; 28 participants are in the Treatment Group and 27 participants in the Delayed Group. Data from the PDD-BI form, the ADOS form, the CARS form and the professional SAS form will be used in this thesis project for analyses. Factors analyzed are age, gender and severity [initial professional SAS data] and then correlating these factors with data from PDD-BI (autism composite score and each subscale), ADOS and CARS. The data analyses show that changing the dietary and nutritional needs of children/adults with autism improves the symptoms of autism (as rated by the PDD-BI) by approximately 22% in the treatment group vs. 3% in the non-treatment group, p<0.001. Overall, these results also suggest that the treatment is equally beneficial for males and females of varying age (young children to adult) and of all severity levels.
ContributorsLee, Chiao May (Author) / Adams, James B. (Thesis director) / Pollard, Elena (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
The goal of this research study was to empirically study a poster-based messaging campaign in comparison to that of a project-based learning approach in assessing the effectiveness of these methods in conveying the scope of biomedical engineering to upper elementary school students. For the purpose of this honors thesis, this research paper specifically reflects and analyzes the first stage of this study, the poster-based messaging campaign. 6th grade students received socially relevant messaging of juniors and seniors at ASU achieving their biomedical aspirations, and received information regarding four crucial themes of biomedical engineering via daily presentations and a website. Their learning was tracked over the course of the weeklong immersion program through a pre/post assessment. This data was then analyzed through the Wilcoxon matched pairs test to determine whether the change in biomedical engineering awareness was statistically significant. It was determined that a poster-based messaging campaign indeed increased awareness of socially relevant themes within biomedical engineering, and provided researchers with tangible ways to revise the study before a second round of implementation. The next stage of the study aims to explain biomedical engineering through engaging activities that stimulate making while emphasizing design-aesthetic appeal and engineering habits of mind such as creativity, teamwork, and communication.
ContributorsSwaminathan, Swetha Anu (Author) / Ganesh, Tirupalavanam (Thesis director) / Shrake, Scott (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
A fetus physiologically relies on blood for nutrients given by the mother. Blood supply is provided to a fetus through an umbilical cord having the structure of two pulsatile arteries with smooth muscle surrounding a thin walled vein. The two arteries transport deoxygenated blood from the fetus in the direction of the placenta while the one vein transports oxygenated blood in the direction of the fetus. This process of the movement of blood is continuous throughout the gestation cycle. Conventionally, there are two arterial coils for every one coil of the vein. Undercoiling and overcoiling of the arteries leads to fetal distress, resulting in researchers to speculate that there is a relationship between these geometries with altered blood flow patterns that may be deleterious to the fetus. The fluid dynamics of an umbilical cord artery blood flow has not been extensively modeled on a computer, meaning there is an absence of knowledge on the ideal pitch of the coiling of the umbilical cord arteries. In this study, I developed computer models with ANSYS Fluent containing fluid dynamic variables and boundary conditions including: density of blood, viscosity of blood, diameter of each artery, pitch of artery coil, flow rate in each artery, and inlet velocity. Care was taken to investigate the effect of fluid finite element size, through mesh refinement, to improve accuracy of the models. The finalized models illustrate velocity and stress distribution in a coiled artery, showing different patterns in a model representing normal as compared to abnormal pitch. Further study of the fluid mechanics in the coil of the umbilical cord arteries, may elucidate the correlation between ideal pitch and fetal distress.
ContributorsSeaney, Amanda Marie (Author) / VanAuker, Michael (Thesis director) / Lilien, Lawrence (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The use of saliva sampling as a noninvasive way for drug analysis as well as the monitoring systems within the body has become increasingly important in recent research. Because of the growing interest in saliva, this project proposes a way to analyze sodium ion concentration in a saliva solution based on its fluorescence level when in the presence of a sodium indicator dye and recorded with a smartphone camera. The dyed sample was placed in a specially designed housing to exclude all ambient light from the images. A source light of known wavelength was used to excite the fluorescent dye and the smartphone camera images recorded the emission light wavelengths. After analysis of the images using ImageJ, it was possible to create a model to determine the level of fluorescence based on sodium ion concentration. The smartphone camera image model was compared to readings from a standard fluorescence plate recorder to test the accuracy of the model. The study found that the model was accurate within 5 % as compared to the fluorescence plate recorder. Based on the results, it was concluded that the method and resulting model proposed in this study is a valid was to analyze saliva or other solutions for their sodium ion concentration via images recorded by a smartphone camera.
ContributorsSmith, Catherine Julia (Author) / Antonio, Garcia (Thesis director) / Caplan, Michael (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Biofeedback music is the integration of physiological signals with audible sound for aesthetic considerations, which an individual’s mental status corresponds to musical output. This project looks into how sounds can be drawn from the meditative and attentive states of the brain using the MindWave Mobile EEG biosensor from NeuroSky. With the MindWave and an Arduino microcontroller processor, sonic output is attained by inputting the data collected by the MindWave, and in real time, outputting code that deciphers it into user constructed sound output. The input is scaled from values 0 to 100, measuring the ‘attentive’ state of the mind by observing alpha waves, and distributing this information to the microcontroller. The output of sound comes from sourcing this into the Musical Instrument Shield and varying the musical tonality with different chords and delay of the notes. The manipulation of alpha states highlights the control or lack thereof for the performer and touches on the question of how much control over the output there really is, much like the experimentalist Alvin Lucier displayed with his concepts in brainwave music.
ContributorsQuach, Andrew Duc (Author) / Helms Tillery, Stephen (Thesis director) / Feisst, Sabine (Committee member) / Barrett, The Honors College (Contributor) / Herberger Institute for Design and the Arts (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05