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- All Subjects: Biomedical Engineering
- Creators: Harrington Bioengineering Program
Description
A noninvasive optical method is developed to monitor rapid changes in blood glucose levels in diabetic patients. The system depends on an optical cell built with a LED that emits light of wavelength 535nm that is a peak absorbance of hemoglobin. As the glucose concentration in the blood decreases, its osmolarity also decreases and the RBCs swell and decrease the path length absorption coefficient. Decreasing absorption coefficient increases the transmission of light through the whole blood. The system was tested with a constructed optical cell that held whole blood in a capillary tube. As expected the light transmitted to the photodiode increases with decreasing glucose concentration. The average response time of the system was between 30-40 seconds. The changes in size of the RBC cells in response to glucose concentration changes were confirmed using a cell counter and also visually under microscope. This method does not allow measuring the glucose concentration with an absolute concentration calibration. It is directed towards development of a device to monitor the changes in glucose concentration as an aid to diabetic management. This method might be improvised for precision and resolution and be developed as a ring or an earring that patients can wear.
ContributorsRajan, Shiny Amala Priya (Author) / Towe, Bruce (Thesis advisor) / Muthuswamy, Jitendran (Committee member) / LaBelle, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2013
Description
Cellular heterogeneity is a key factor in various cellular processes as well as in disease development, especially associated with immune response and cancer progression. Cell-to-cell variability is considered to be one of the major obstacles in early detection and successful treatment of cancer. Most present technologies are based on bulk cell analysis, which results in averaging out the results acquired from a group of cells and hence missing important information about individual cells and their behavior. Understanding the cellular behavior at the single-cell level can help in obtaining a complete profile of the cell and to get a more in-depth knowledge of cellular processes. For example, measuring transmembrane fluxes oxygen can provide a direct readout of the cell metabolism.
The goal of this thesis is to design, optimize and implement a device that can measure the oxygen consumption rate (OCR) of live single cells. A microfluidic device has been designed with the ability to rapidly seal and unseal microchambers containing individual cells and an extracellular optical oxygen sensor for measuring the OCR of live single cells. The device consists of two parts, one with the sensor in microwells (top half) and the other with channels and cells trapped in Pachinko-type micro-traps (bottom half). When the two parts of the device are placed together the wells enclose each cell. Oil is flown in through the channels of the device to produce isolated and sealed microchamber around each cell. Different fluids can be flowed in and out of the device, alternating with oil, to rapidly switch between sealed and unsealed microenvironment around each cell. A fluorescent ratiometric dual pH and oxygen sensor is placed in each well. The thesis focuses on measuring changes in the oxygen consumption rate of each cell within a well. Live and dead cells are identified using a fluorescent live/dead cell assay. Finally, the technology is designed to be scalable for high-throughput applications by controlling the flow rate of the system and increasing the cell array density.
The goal of this thesis is to design, optimize and implement a device that can measure the oxygen consumption rate (OCR) of live single cells. A microfluidic device has been designed with the ability to rapidly seal and unseal microchambers containing individual cells and an extracellular optical oxygen sensor for measuring the OCR of live single cells. The device consists of two parts, one with the sensor in microwells (top half) and the other with channels and cells trapped in Pachinko-type micro-traps (bottom half). When the two parts of the device are placed together the wells enclose each cell. Oil is flown in through the channels of the device to produce isolated and sealed microchamber around each cell. Different fluids can be flowed in and out of the device, alternating with oil, to rapidly switch between sealed and unsealed microenvironment around each cell. A fluorescent ratiometric dual pH and oxygen sensor is placed in each well. The thesis focuses on measuring changes in the oxygen consumption rate of each cell within a well. Live and dead cells are identified using a fluorescent live/dead cell assay. Finally, the technology is designed to be scalable for high-throughput applications by controlling the flow rate of the system and increasing the cell array density.
ContributorsRodrigues, Meryl (Author) / Meldrum, Deirdre (Thesis advisor) / Kelbauskas, Laimonas (Committee member) / LaBelle, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2014
Description
In the search for chemical biosensors designed for patient-based physiological applications, non-invasive diagnostic approaches continue to have value. The work described in this thesis builds upon previous breath analysis studies. In particular, it seeks to assess the adsorptive mechanisms active in both acetone and ethanol biosensors designed for breath analysis. The thermoelectric biosensors under investigation were constructed using a thermopile for transduction and four different materials for biorecognition. The analytes, acetone and ethanol, were evaluated under dry-air and humidified-air conditions. The biosensor response to acetone concentration was found to be both repeatable and linear, while the sensor response to ethanol presence was also found to be repeatable. The different biorecognition materials produced discernible thermoelectric responses that were characteristic for each analyte. The sensor output data is presented in this report. Additionally, the results were evaluated against a mathematical model for further analysis. Ultimately, a thermoelectric biosensor based upon adsorption chemistry was developed and characterized. Additional work is needed to characterize the physicochemical action mechanism.
ContributorsWilson, Kimberly (Author) / Guilbeau, Eric (Thesis advisor) / Pizziconi, Vincent (Thesis advisor) / LaBelle, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2011
Description
Olecranon fractures account for approximately 10% of upper extremity fractures and 95% of them require surgical fixation. Most of the clinical, retrospective and biomechanical studies have supported plate fixation over other surgical fixation techniques since plates have demonstrated low incidence of reoperation, high fixation stability and resumption of activities of daily living (ADL) earlier. Thus far, biomechanical studies have been helpful in evaluating and comparing different plate fixation constructs based on fracture stability. However, they have not provided information that can be used to design rehabilitation protocols such as information that relates load at the hand with tendon tension or load at the interface between the plate and the bone. The set-ups used in biomechanical studies have included simple mechanical testing machines that either measured construct stiffness by cyclic loading the specimens or construct strength by performing ramp load until failure. Some biomechanical studies attempted to simulate tendon tension but the in-vivo tension applied to the tendon remains unknown. In this study, a novel procedure to test the olecranon fracture fixation using modern olecranon plates was developed to improve the biomechanical understanding of failures and to help determine the weights that can be safely lifted and the range of motion (ROM) that should be performed during rehabilitation procedures.
Design objectives were defined based on surgeon's feedback and analysis of unmet needs in the area of biomechanical testing. Four pilot cadaveric specimens were prepared to run on an upper extremity feedback controller and the set-up was validated based on the design objectives. Cadaveric specimen preparation included a series of steps such as dissection, suturing and potting that were standardized and improved iteratively after pilot testing. Additionally, a fracture and plating protocol was developed and fixture lengths were standardized based on anthropometric data. Results from the early pilot studies indicated shortcomings in the design, which was then iteratively refined for the subsequent studies. The final pilot study demonstrated that all of the design objectives were met. This system is planned for use in future studies that will assess olecranon fracture fixation and that will investigate the safety of rehabilitation protocols.
Design objectives were defined based on surgeon's feedback and analysis of unmet needs in the area of biomechanical testing. Four pilot cadaveric specimens were prepared to run on an upper extremity feedback controller and the set-up was validated based on the design objectives. Cadaveric specimen preparation included a series of steps such as dissection, suturing and potting that were standardized and improved iteratively after pilot testing. Additionally, a fracture and plating protocol was developed and fixture lengths were standardized based on anthropometric data. Results from the early pilot studies indicated shortcomings in the design, which was then iteratively refined for the subsequent studies. The final pilot study demonstrated that all of the design objectives were met. This system is planned for use in future studies that will assess olecranon fracture fixation and that will investigate the safety of rehabilitation protocols.
ContributorsJain, Saaransh (Author) / Abbas, James (Thesis advisor) / LaBelle, Jeffrey (Thesis advisor) / Jacofsky, Marc (Committee member) / Arizona State University (Publisher)
Created2015
Description
The importance of efficient design and development teams in in 21st century is evident after the compressive literate review was performed to digest various aspects of benefits and foundation of teamwork. Although teamwork may have variety of applications in many different industries, the new emerging biomedical engineering is growing significantly using principles of teamwork. Studying attributes and mechanism of creating successful biomedical engineering teams may even contribute more to the fast paste growth of this industry. In comprehensive literate review performed, general importance of teamwork was studied. Also specific hard and soft attributes which may contribute to teamwork was studied. Currently, there are number of general assessment tools which assists managements in industry and academia to systematically bring qualified people together to flourish their talents and skills as members of a biomedical engineering teams. These assessment tools, although are useful, but are not comprehensive, incorporating literature review attributes, and also doesn't not contain student perspective who have experience as being part of a design and development team. Although there are many scientific researches and papers designated to this matter, but there is no study which purposefully studies development of an assessment tool which is designated to biomedical engineering workforce and is constructed of both literature, current assessment tools, and also student perspective. It is hypothesized that a more comprehensive composite assessment tool that incorporate both soft and hard team attributes from a combined professional and student perspective could be implemented in the development of successful Biomedical Engineering Design and Development teams and subsequently used in 21st century workforce.
ContributorsAfzalian Naini, Nima (Author) / Pizziconi, Vincent (Thesis director) / Ankeny, Casey (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Abstract
The aim of the research performed was to increase research potential in the field of cell stimulation by developing a method to adhere human neural progenitor cells (hNPC’s) to a sterilized stretchable microelectrode array (SMEA). The two primary objectives of our research were to develop methods of sterilizing the polydimethylsiloxane (PDMS) substrate being used for the SMEA, and to derive a functional procedure for adhering hNPC’s to the PDMS. The proven method of sterilization was to plasma treat the sample and then soak it in 70% ethanol for one hour. The most successful method for cell adhesion was plasma treating the PDMS, followed by treating the surface of the PDMS with 0.01 mg/mL poly-l-lysine (PLL) and 3 µg/cm2 laminin. The development of these methods was an iterative process; as the methods were tested, any problems found with the method were corrected for the next round of testing until a final method was confirmed. Moving forward, the findings will allow for cell behavior to be researched in a unique fashion to better understand the response of adherent cells to physical stimulation by measuring changes in their electrical activity.
The aim of the research performed was to increase research potential in the field of cell stimulation by developing a method to adhere human neural progenitor cells (hNPC’s) to a sterilized stretchable microelectrode array (SMEA). The two primary objectives of our research were to develop methods of sterilizing the polydimethylsiloxane (PDMS) substrate being used for the SMEA, and to derive a functional procedure for adhering hNPC’s to the PDMS. The proven method of sterilization was to plasma treat the sample and then soak it in 70% ethanol for one hour. The most successful method for cell adhesion was plasma treating the PDMS, followed by treating the surface of the PDMS with 0.01 mg/mL poly-l-lysine (PLL) and 3 µg/cm2 laminin. The development of these methods was an iterative process; as the methods were tested, any problems found with the method were corrected for the next round of testing until a final method was confirmed. Moving forward, the findings will allow for cell behavior to be researched in a unique fashion to better understand the response of adherent cells to physical stimulation by measuring changes in their electrical activity.
ContributorsBridgers, Carson (Co-author) / Peterson, Mara (Co-author) / Stabenfeldt, Sarah (Thesis director) / Graudejus, Oliver (Committee member) / Harrington Bioengineering Program (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The Honors Thesis involved the use of vertically-aligned, piezoelectric nanowire sensor arrays configured by Dr. Henry A. Sodano and Dr. Aneesh Koka from the University of Florida, in order to acquire acceleration data. Originally, the project was focused on interfacing and calibrating the barium titanate (BaTio3) sensors to measure wall shear stress, a fluid dynamic characteristic. In order to gain an understanding of these novel piezoelectric sensors, the experiments performed by Sodano and Koka were to be investigated, replicated, and results reproduced. After initial trial phases, signals failed to be consistently measured from the sensors and the project's emphasis was re-defined. The outlined goals were 1) to re-design the initial system used for signal acquisition, 2) test the improved signal acquisition system, 3) successfully measure output signals from the BaTiO3 nanowire sensors, and 4) determine the cause for inconsistent signal measurements from the piezoelectric nanawire sensors. Following a detailed review of the previous experimental procedures and the initial signal acquisition system, an improved acquisition system was designed and its expected behavior was tested and verified. Despite the introduction of the improved acquisition system, voltage outputs were unable to be measured as a function of shaker table acceleration. It was impossible to verify the effect of the improved signal acquisition system on the measured BaTiO3 nanowire sensor output. Based on an analysis of data collected using a commercial 3-axis acceleromoeter, it is hypothesized that the BaTiO3 nanowire sensors were broken after the first experimental trial due to an excessively applied force from an external source (i.e. shaker table, improper handling during experimentation, and/or improper handling during transportation).
ContributorsThomas, Jonah (Author) / Frakes, David (Thesis director) / LaBelle, Jeffrey (Contributor) / Barrett, The Honors College (Contributor)
Created2014-05
Description
The purpose of this project was to examine the viability of protein biomarkers in pre-symptomatic detection of lung cancer. Regular screening has been shown to vastly improve patient survival outcome. Lung cancer currently has the highest occurrence and mortality of all cancers and so a means of screening would be highly beneficial. In this research, the biomarker neuron-specific enolase (Enolase-2, eno2), a marker of small-cell lung cancer, was detected at varying concentrations using electrochemical impedance spectroscopy in order to develop a mathematical model of predicting protein expression based on a measured impedance value at a determined optimum frequency. The extent of protein expression would indicate the possibility of the patient having small-cell lung cancer. The optimum frequency was found to be 459 Hz, and the mathematical model to determine eno2 concentration based on impedance was found to be y = 40.246x + 719.5 with an R2 value of 0.82237. These results suggest that this approach could provide an option for the development of small-cell lung cancer screening utilizing electrochemical technology.
ContributorsEvans, William Ian (Author) / LaBelle, Jeffrey (Thesis director) / Spano, Mark (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Determining the characteristics of an object during a grasping task requires a combination of mechanoreceptors in the muscles and fingertips. The width of a person's finger aperture during the grasp may affect the accuracy of how that person determines hardness, as well. These experiments aim to investigate how an individual perceives hardness amongst a gradient of varying hardness levels. The trend in the responses is assumed to follow a general psychometric function. This will provide information about subjects' abilities to differentiate between two largely different objects, and their tendencies towards guess-chances upon the presentation of two similar objects. After obtaining this data, it is then important to additionally test varying finger apertures in an object-grasping task. This will allow an insight into the effect of aperture on the obtained psychometric function, thus ultimately providing information about tactile and haptic feedback for further application in neuroprosthetic devices. Three separate experiments were performed in order to test the effect of finger aperture on object hardness differentiation. The first experiment tested a one-finger pressing motion among a hardness gradient of ballistic gelatin cubes. Subjects were asked to compare the hardness of one cube to another, which produced the S-curve that accurately portrayed the psychometric function. The second experiment utilized the Phantom haptic device in a similar setup, using the precision grip grasping motion, instead. This showed a more linear curve; the percentage reported harder increased as the hardness of the second presented cube increased, which was attributed to both the experimental setup limitations and the scale of the general hardness gradient. The third experiment then progressed to test the effect of three finger apertures in the same experimental setup. By providing three separate testing scenarios in the precision grip task, the experiment demonstrated that the level of finger aperture has no significant effect on an individual's ability to perceive hardness.
ContributorsMaestas, Gabrielle Elise (Author) / Helms Tillery, Stephen (Thesis director) / Tanner, Justin (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
With an increased demand for more enzyme-sensitive, bioresorbable and more biodegradable polymers, various studies of copolymers have been developed. Polymers are widely used in various applications of biomedical engineering such as in tissue engineering, drug delivery and wound healing. Depending on the conditions in which polymers are used, they are modified to accommodate a specific need. For instance, polymers used in drug delivery are more efficient if they are biodegradable. This ensures that the delivery system does not remain in the body after releasing the drug. It is therefore crucial that the polymer used in the drug system possess biodegradable properties. Such modification can be done in different ways including the use of peptides to make copolymers that will degrade in the presence of enzymes. In this work, we studied the effect of a polypeptide GAPGLL on the polymer NIPAAm and compare with the previously studied Poly(NIPAAm-co-GAPGLF). Both copolymers Poly(NIPAAm-co-GAPGLL) were first synthesized from Poly(NIPAAm-co-NASI) through nucleophilic substitution by the two peptides. The synthesis of these copolymers was confirmed by 1H NMR spectra and through cloud point measurement, the corresponding LCST was determined. Both copolymers were degraded by collagenase enzyme at 25 ° C and their 1H NMR spectra confirmed this process. Both copolymers were cleaved by collagenase, leading to an increase in solubility which yielded a higher LCST compared to before enzyme degradation. Future studies will focus on evaluating other peptides and also using other techniques such as Differential Scanning Microcalorimetry (DSC) to better observe the LCST behavior. Moreover, enzyme kinetics studies is also crucial to evaluate how fast the enzyme degrades each of the copolymers.
ContributorsUwiringiyimana, Mahoro Marie Chantal (Author) / Vernon, Brent (Thesis director) / Nikkhah, Mehdi (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05