Summer 2023
Design and Test of a Mechanical System for Electrochemical Oxygen Sensors with in vivo Applications
Dominic Bednar
Mechanical Engineering, Michigan State University
Advisor: Mark Allen
Mentor: Vishal Venkatesh
A freestanding micromachined electrochemical oxygen sensor has been developed for the purpose of minimally invasive biomedical applications. When applied to these physiological environments, it is important to understand the physical interactions between this environment and the sensor. These interactions could affect the functionality of the sensor. An anticipated use is applying this sensor within a muscle, which has unknown effects on the sensor. To validate the performance of the sensor in a muscular environment, a mechanical system has been developed that tests the sensor in these conditions using an externally applied force and a muscle phantom. For performance comparison, the sensor was tested in saline before and after experiencing an applied load, that progressively increased, within the phantom. After undergoing testing, this comparison showed no significant difference in current output validating that intramuscular forces have minimal to no significant effect on the performance of these sensors.
Spin-Lattice Relaxation Times of Nitrogen-Vacancy Centers in Diamond
Pravan Chakravarthy
Physics, University of Chicago
Advisor: Lee Bassett
Mentor: Rebecca Fishman
The nitrogen-vacancy (NV) center is a point defect in diamond that has applications in quantum computing, biomedicine, and other fields. Its chemical and physical properties enable it to function as a spin qubit for quantum information processing. NV centers can also be utilized in improving the quality of nanoscale medical imaging, particularly important to which is the spin-lattice relaxation time (T1) of a given quantum system. In this research, T1 measurements on nanodiamonds (NDs) are conducted and relaxation rates 1/T1 are analyzed as a function of ND size. An increase in size is found to correspond with a decrease in relaxation rate, and is compared to a previous study. The results shed some light into the optimal choice of size for computing and biosensing applications, but leave plenty of room for further research.
Design, Fabrication, and Analysis of Customized High-density MXene Bioelectronics for Upper and Lower Limb Muscles
Ariana A. Gonzalez
Mechanical Engineering, University of Puerto Rico at Mayaguez
Advisor: Flavia Vitale
Mentors: Raghav Garg, Maggie Wagner
High-resolution Ti3C2Tx MXene wearable bioelectronics are a novel technology that shows great advantages in the recording of high-density surface electromyography (HD-sEMG) data, useful to determine muscle activation patterns in the desired area as the patient moves. MXenes are a new class of bioelectronic materials that prove to be highly functional in the creation of medical devices due to their biocompatibility with the human body. The goal of this investigation was to create multiple customizable MXtrodes to perform electromyography (sEMG) on the upper and lower limbs of amputees or patients with muscle movement difficulties to provide them with an accurate diagnosis. The interest of this technology is to provide patients with an economical, comfortable, and highly detailed alternative to conventional electrodes that require uncomfortable and irritating conductive gels. The versatility, simplicity, and scalability of the fabrication process of these new types of electrodes enable the creation of customized electrodes with different geometries for any part of the body with a low-cost manufacturing process. Multiple sets of high-resolution MXene wearable electrodes were designed and fabricated for upper and lower limb muscles and some of them were tested on human subjects. Spatial maps were generated with the obtained data to compare the muscle activation patterns at each point where the MXtrodes were placed to eventually use this data in future applications, like providing medical diagnostics, and rehabilitation to the patients with the use of assistive technologies like the control of prosthetics.
A Chronically Stable Polymer Adhesive for Bioelectronics
J. Brock Horton
Biomedical Engineering and Chemistry, University of Alabama at Birmingham
Advisor: Yuanwen Jiang
Mentors: Yaxin Fan, Yewei Huang
In biomedical applications, strong, long-term adhesion onto wet tissue is necessary for device-to-biological tissue positioning. Current methods often employ the use of crosslinked hydrogels that swell and lose mechanical and adhesion properties over time during in vivo conditions. To overcome the above limits of hydrogel biointerfaces, this paper aims to design a chemically stable polymer adhesive to achieve a chronically stable and strong adhesive for biomedical device applications. The long-term stability of this polymer adhesive will not be compromised by dehydration or excess swelling, which are the two main shortcomings of conventional hydrogels. Therefore, it shows a promising future for long-term implantable applications in biomedical devices.
Optimizing Fabrication and Optical Detection of Battery-Free Colorimetric Leaf Sensors
Brian Huang
Mechanical Engineering, Purdue University
Advisor: Cherie Kagan
Mentors: Shobhita Kramadhati, Chavez Lawrence, Akhila Mallavarapu
Leaf moisture and leaf microenvironment plays an important role in determining overall crop health. Commercial leaf sensors require power supply and are expensive. Colorimetric metasurface-based sensors integrated with moisture-sensitive biopolymers are biodegradable, optical, and battery free sensors that can be detected by ground and aerial robots. In this project, we look at two parts: building a custom tool for low-cost sensor fabrication using nanocrystals, and developing an image processing algorithms to interrogate the optical sensors attached to leaves.
Developing an Optical System with a Confocal Chromatic Sensor for Microscopic Robot Characterization
Morgan Jones
Mechanical Engineering, Howard University
Advisor: Marc Miskin
Mentors: Will Reinhardt, Kyle Skelil
Robotics is a vast and varied field, a field that is developing on the microscopic scale. Microscopic robots offer unprecedented opportunities due to their small size, smaller than what the naked eye can see. Micro-robots are primarily made of photovoltaic and operate in fluids. They move because of the generated voltage from the photovoltaic that causes controlled fluid flows that move the robot. We have a limited understanding of precise measurements of robots, specifically robot topography. A way to get the precision measurements from the robots despite their small size is to use a Confocal Chromatic Sensor, which uses controlled chromatic aberration to disperse white light into wavelengths, assigns each wavelength a distance and detects that wavelength to measure for distance. However, the sensor is severely limited: it has a small measuring range and cannot be utilized with a microscope. Here, we address this barrier by developing an optical system that collimates and refocuses the sensor beam for utilization. The optical system utilizes achromatic lenses that account for the chromatic aberration that is present in the confocal chromatic sensor. We demonstrate the success of the collimation in the system is successful by refocusing the beam back into a single point. These results are significant because this system would be used to characterize the topography of the micro robots, which will be used to gain greater knowledge on other aspects of the micro robots, like their speed, and lead to an expansion of the field of micro-robotics.
Design and Experimentation of Complex Dynamical Systems for Intelligent Navigation
Nathan Phan
Chemical Engineering, The Ohio State University
Advisor: Ani Hsieh
Mentors: Victoria Edwards, Thales C. Silva
Managing the consumption of resources exists regardless of discipline. In the case of oceanic endeavors, this principle manifests due to both energetic and physical constraints, including fuel and motor capabilities. In order to advance our understanding of robotic systems and interactions, we must learn to overcome these obstacles, one method being more intelligent planning through the various complex flows found in practice. Evolving to meet this goal involves three discrete steps: fabrication of these complex flows, implementation of algorithms to build intelligence, and experimentation using the previously developed miniature autonomous surface vehicles (mASV). This paper details the first two steps, exploring the process, results, and other applications of each. Numerical integration of complex flows were developed within Python, improving our intuition detailing their characteristics and properties of formation. Once sufficient, miniature flows were conceived, translating theory into experiment, finally scaling into the Multi-Robot Tank. After modeling these complex flows, focus shifted to quantitative and qualitative analysis of them, with hopes of translating the trends into a data structure, whereupon algorithms for intelligent navigation to be implemented. Implications of the findings further our capabilities with the limited resources at hand, allowing more efficient boats and testing.
Evaluation of Packaging for Soil-Degradable Sensors
Manasa P. Sripati
Biomedical Engineering, University of Texas at Austin
Advisor: Kevin T. Turner
Mentors: Gokulanand M. Iyer, Elizabeth V. Schell
Internet of things (IoT) systems for precision agriculture have the potential to conserve water and increase agricultural productivity. Enabling these systems with a capacitive moisture sensor, which is fully biodegradable paper substrate with a cellulose nanofibrils surface, helps detect moisture levels of soil in agricultural fields. But these soil-degradable sensors degrade very rapidly without a packaging to protect the sensor. Therefore, a need to develop a biodegradable packaging that can effectively extend the lifespan of these sensors while maintaining sensor performance and functionality is required. Several packaging designs have been investigated to identify a design that will most effectively protect the sensor, and the mechanical properties of 3:1 beeswax: soy wax composite wax blend are analyzed. A packaging design and material are selected and recommended as an appropriate biodegradable packaging for these soil-degradable sensors.
Imaging Photoplethysmography to Determine Pressure Induced Changes in Cutaneous Blood Volume
Alexander Steele
Electrical Engineering, University of Notre Dame
Advisor: Andrew Richardson
Mentors: Andrew Gabros, Avin Khera
The assessment of cutaneous blood volume in the hand and its response to external stimuli is crucial for many innovative techniques in medicine, including guiding research in optical peripheral implants. However, traditional methods for measuring blood flow dynamics, such as Laser Doppler Flowmetry (LDF) and Hyperspectral Imaging (HSI), demonstrate limitations in field-of-view of analyzed tissues. The emergence of imaging photoplethysmography (iPPG) has enabled both non-contact and spatially resolved measurements of cutaneous perfusion. In this study, we present the implementation of iPPG to investigate pressure-induced changes in cutaneous blood volume within the hand. We have successfully developed an iPPG system capable of capturing perfusion changes in the hand under varying pressure conditions. High-resolution imaging, along with advanced image processing algorithms, were employed to extract physiological information from specific videos of the hand under different forces. A microscope stand mounted with a camera, ultrawide-angle lens, LED ring, and 3D printed clear-resin force probe were used to obtain high-resolution videos of the volar hand surface. The Plane-Orthogonal-to-Skin algorithm was then utilized to provide spatial maps of cutaneous perfusion in the hand. This project not only advances our understanding of cutaneous vascular dynamics in the hand but will guide the design of peripheral brain-computer interface implants. Furthermore, it will contribute to the development of optical PPG peripheral force sensors by identifying ideal implantation locations in the hand.
Analysis of Commercially Available Electrical Components for Amplification of Quantum Processor Read Out
Eric Zhang
Computer Science, Ohio State University
Advisor: Anthony Sigillito
Mentors: Seongwoo Oh, Mridul Pushp
Amplifiers for quantum processors are required to function at cryogenic temperatures near 850 millikelvin to enable the measurement of state changes in single electron transmitters (SET). However, minimal data has been collected on the functionalities of various electrical components below 4 K. In this work we measured a select number of commercially available capacitors, resistors, and transistors in an ICEOxford cryostat and report the change in component parameters as a function of temperature. Using these values, we simulated our cryogenic amplifier circuits to better understand circuit performance at low temperatures. We hope these results will enable the engineering of better amplifiers for the SETs.