Matching Items (53)

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Utilization of Electrochemical Impedance Spectroscopy for the Detection of QSOX1 and CEA

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

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.

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  • 2017-05

Towards the Development of a Multimarker Platform for Point-of-Care Monitoring of Solid Organ Transplant Patient Health through Impedance-Time Testing of Tacrolimus Cystatin-C, and IL-12

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

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.

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Date Created
  • 2017-05

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Characterization and Optimization of Ion-Sensitive Field Effect Transistors for Rapid Personalized Diagnostics

Description

The growth of the medical diagnostic industry in the past several decades has largely been due to the creation and iterative optimization of bio sensors. Recent pushes towards value added

The growth of the medical diagnostic industry in the past several decades has largely been due to the creation and iterative optimization of bio sensors. Recent pushes towards value added as well as preventative health care has made point of care devices more attractive to health care providers. Rapid detection for diseases and cancers is done with a bio sensor, which a broad term used to describe an instrument which uses a bio chemical reaction to detect a chemical compound with the use of a bio recognition event in addition to a signal detection event. The bio sensors which are presented in this work are known as ion-sensitive field effects transistors (ISFETs) and are similar in function to a metal oxide field effect transistor (MOSFET). These ISFETs can be used to sense pH or the concentration of protons on the surface of the gate channel. These ISFETs can be used for certain bio recognition events and this work presents the application of these transistors for the quantification of tumor cell proliferation. This includes the development of a signal processing and acquisition system for the long term assessment of cellular metabolism and optimizing the system for use in an incubator. This thesis presents work done towards the optimization and implementation of complementary metal\u2014oxide\u2014semiconductor (CMOS) ISFETs as well as remote gate ISFETs for the continuous assessment of tumor cell extracellular pH. The work addresses the challenges faced with the fabrication and optimization of these sensors, which includes the mitigation of current drift with the use of pulse width modulation in addition to issues encountered with fabrication of electrodes on a quartz substrate. This work culminates in the testing of an autonomous system with mammary tumor cells as well as the assessment of cell viability in an incubator over extended periods. Future applications of this work include the creation of a remote gate ISFET array for multiplexed detection as well as the implementation of ISFETs for bio marker detection via an immunoassay.

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Date Created
  • 2017-05

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Proof of Concept of Pseudo-Continuous Monitoring of L-Lactate Levels Using Electrochemical Impedance Spectroscopy

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

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.

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Date Created
  • 2017-05

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Ebola Hemorrhagic Fever: The Game

Description

The goal of this project was to create a card game that would quickly and easily allow medical professionals to learn important information. This project seeks to advance ways in

The goal of this project was to create a card game that would quickly and easily allow medical professionals to learn important information. This project seeks to advance ways in which medical staff gain information about disease outbreaks through the creation of a card game which teaches players the proper steps and procedure to triage and treat patients who are suspected to have Ebola Hemorrhagic Fever, which was not done properly during the recent outbreak. To create this game, research was conducted on the information given by the Center for Disease Control and Prevention (CDC) on the various steps to triaging those who were suspected of having Ebola. Various prototypes of the game were made and tested to optimize the win-lose ratio while still being an enjoyable game to play. This card game is fast-paced, small, and can be played either individually or with more than one person. It is loosely based off of Solitaire. This game has gone through three prototypes of the cards as well as a few brief testing periods. Through the methods and procedure used in this game's creation, it has been concluded that this method is a great way to easily teach players a proper procedure, and that this method of game can be applied to other disease breakouts and even to other fields where information must be learned quickly. Future steps for this game include improving the graphic art used in the cards, and continuing on to create a smartphone application.

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Date Created
  • 2015-12

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The Development of a Simplified and Integrated Glucose-Monitoring Biosensor for Diabetics

Description

Self-monitoring of blood glucose (SMBG) is the standard of care in diabetes management. Current technologies for SMBG are based upon enzymatic electrochemical (amperometric) sensing. To increase the sensitivity and specificity

Self-monitoring of blood glucose (SMBG) is the standard of care in diabetes management. Current technologies for SMBG are based upon enzymatic electrochemical (amperometric) sensing. To increase the sensitivity and specificity of current devices, a novel method of detecting glucose using electrochemical impedance spectroscopy (EIS) technology is explored. To test the ability of EIS methods to detect glucose, the enzyme glucose oxidase (GOx) was fixed to gold electrodes through the means of a specific immobilization process. Once GOx was fixed to the gold electrode surface, a 5 mV sine wave sweeping frequencies from 100 kHz to 1 Hz was induced at a glucose range 0-500 mg/dL mixed with a ferricyanide redox mediator. Each frequency in the impedance sweep was analyzed for highest response and R-squared value. The frequency with both factors optimized is specific for the glucose-GOx binding interaction, and was determined to be 1.17 kHz in purified solutions. Four separate electrodes were constructed and date from each were averaged. The correlation between the impedance response and concentration at the low range of detection (0-100 mg/dL of gluose) was determined to be 3.19 ohm/ln (mg/dL) with an R-squared value of 0.86. Its associated lower limit of detection was found to be 41 mg/dL. The same frequency of 1.17 kHz was then verified in whole blood under the glucose range of 0-100 mg/dL while diluting the blood to observe effect. As the blood concentration increased, the response of the sensor decreased logarithmically. The maximized blood detection volume was determined to be 25% whole blood suggesting dilution, coatings, or filtration is required for future adaptation. The above data confirms that EIS offers a new method of glucose detection as an alternative technology for SMBG and offers improved detection at lower concentrations of glucose. The unique frequency response of individual markers allows for modulation of signals so that several markers could be measured with a single sensor. Future work includes assessment of other diabetes associated biomarkers that can be measured on a single sensor, integration testing and tuning of the biomarkers, impedance-time sensing development, and finally, testing on control subjects.

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Date Created
  • 2012-05

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Sickle Cell Disease and the Need for Neonatal Testing Programs in Africa, with an Emphasis on Kenya

Description

Sickle cell disease is a genetic disorder that can cause substantial helath problems. It is the result of a mutation in the DNA coding for hemoglobin. As a result of

Sickle cell disease is a genetic disorder that can cause substantial helath problems. It is the result of a mutation in the DNA coding for hemoglobin. As a result of changes in two important amino acids, a person suffering from sickle cell disease will have erythrocytes that do not maintain the typical biconcave shape and instead for a crescent shape. Individuals with sickle cell disease may have many health problems tied to their irregular hemoglobin. The unusual shape of the erythrocytes leads to a much shorter cell life, which means that even though bone marrow remains active long past childhood to try to keep up with the loss of erythrocytes, the body is still unable to accommodate the rapid death of erythrocytes. The malformed erythrocytes can also cause vascular occlusion, blocking blood vessels and slowing blood flow. While sickle cell disease has the potential to spread worldwide, it is particularly common in Africa. This may be because people with the sickle cell trait have a high resistance to malaria, making them more likely to survive that ubiquitous disease and pass on their traits to their offspring. However, the mortality rate in young children with sickle cell disease is very high, in part because the spleen, already stressed by filtering out dead erythrocytes, has difficulties filtering out bacteria. One of the keys to stopping the spread of the disease is neonatal screening, but this requires specialized equipment that is fairly uncommon in rural areas, as can be seen in Kenya. Therefore, it would be highly beneficial to develop a more cost-effective and widely available method for testing for sickle cell disease.

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  • 2012-05

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Lightweight Transradial Prosthetic Able to Withstand Mechanical Forces during a Human Fall

Description

This paper proposes a new framework design for the lightweight transradial prosthesis. This device was designed to be light-weight, easily manufactured, inexpensive, and to have a high interstitial free space

This paper proposes a new framework design for the lightweight transradial prosthesis. This device was designed to be light-weight, easily manufactured, inexpensive, and to have a high interstitial free space volume for electrical components and customization. Press-fit junctions between fins allow for little or no adhesives, allowing for easily replaceable parts. Designs were constructed out of chipboard and run through an assortment of tests to see if each design iterations met structural design specifications. There were four main design iterations tested: 4, 8, 12 fin designs, and a 4 fin design with additional angled fins for torsional support (4T). Compression, torsion, and 3-point bending tests were all performed on each cylindrical iteration. Basic tensile and material testing was done on chipboard to support results. The force applied to a human arm during a fall is approximately 500 lbf [13]. Compression tests yielded a strength of approximately 300 lbf for the cylindrical designs. ANOVAs and T-tests were performed to find significance in compressive strength between the design iterations with the varied number of fins (p<<0.05). The torsional strength of the human arm, without causing great strain or discomfort has a max value of approximately 15 Nm [14]. This matched the torsional values of the 4T. design [14]. The 4, 8, and 12 designs' torsional strengths were linear with values of approximately 4, 7, and 12 Nm respectively. The 3-point bending test yielded the flexural stress and strain values to find compressive strength in the convex direction as well as the displacement and deformation in each sample. The material chipboard was found to be variable with elastic modulus, Poisson's ratio, and tensile strength. Each experimental procedure was done as a proof of concept for future prosthesis design.

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  • 2016-05

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Heart Rate Variability and Electrocardiography in Evaluating Stress

Description

Chronic stress has been linked as a probable contributor to a number of health problems that plague the world today. Obesity, cardiovascular disease, depression, and osteoporosis are all common health

Chronic stress has been linked as a probable contributor to a number of health problems that plague the world today. Obesity, cardiovascular disease, depression, and osteoporosis are all common health risks believed to be exacerbated by stress. While it is nether realistic nor desirable to completely eliminate stress in an individual, proper stress management is important to a healthy lifestyle. Homeostasis is the primary mechanism by which stress, and the stress response, should be analyzed. Environmental factors known as stressors elicit responses from the body, which can be measured in terms of duration and magnitude. These two factors determine the homeostatic response from the body. This thesis proposes the study of heart rate variability (HRV) to measure the response of the autonomic nervous system through time domain analysis (the length of interbeat intervals) and frequency domain analysis (the differences between the lengths of consecutive interbeat intervals). Even with many possible problems, this data still represents valuable proof of concept that HRV analysis may be of use in identifying stress.

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Date Created
  • 2012-05

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An Investigation into the Causes of Insulin Aggregation

Description

Insulin is an essential peptide hormone that aides in the metabolism of glucose by allowing the cells to uptake glucose. Exogenous insulin is often prescribed to patients in order to

Insulin is an essential peptide hormone that aides in the metabolism of glucose by allowing the cells to uptake glucose. Exogenous insulin is often prescribed to patients in order to help manage their diabetes. Recent research has indicated that prescription insulin is not at the labeled concentration when the prescription is filled by the patient. This decrease in concentration from when the insulin is manufactured to when it reaches the pharmacy is likely due to the insulin denaturing and aggregating. Dynamic light scattering is a useful and accurate method to determine the hydrodynamic radius of a solute and can be used to measure the hydrodynamic radius of insulin which will thus determine the aggregation of the sample since the more aggregated it is, the larger the hydrodynamic radius will be. By testing the effect of pH, concentration, temperature, and time on insulin samples, the optimal storage conditions can be determined in order to ensure researchers and patients are not using aggregated insulin. No conclusive relationship was found between any variable and sample diameter, but several trends were identified. Temperature, pH, and time in solution are all factors that could impact the aggregation, and therefore activity, of insulin. However, concentration did not show any trend regarding aggregation. Determining the relationships between these variables could allow for the identification of ideal storage conditions for researchers. Additionally, it can be used to identify shortcomings in the insulin supply chain.

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Date Created
  • 2018-05