Biomedical Engineering and Bioengineering Commons^™

Adaptive Octree Meshes For Simulation Of Extracellular Electrophysiology, Christopher Bc Girard, Dong Song

Engineering Faculty Articles and Research

Objective. The interaction between neural tissues and artificial electrodes is crucial for understanding and advancing neuroscientific research and therapeutic applications. However, accurately modeling this space around the neurons rapidly increases the computational complexity of neural simulations. Approach. This study demonstrates a dynamically adaptive simulation method that greatly accelerates computation by adjusting spatial resolution of the simulation as needed. Use of an octree structure for the mesh, in combination with the admittance method for discretizing conductivity, provides both accurate approximation and ease of modification on-the-fly. Main results. In tests of both local field potential estimation and multi-electrode stimulation, dynamically adapted meshes …

Advanced Processing Techniques For Electrospun Nanofibers: Investigating Annealing And Laser Zone-Drawing Effects On Material Characteristics, Matthew D. Flamini

Theses and Dissertations

Electrospun nanofibers hold potential for a wide range of commercial and scientific applications; however, their properties must be optimized through post-processing treatments to achieve optimal performance. This dissertation investigates the effects of annealing and laser zone-drawing on electrospun nanofiber properties. Annealing polycaprolactone nanofibers at 70°C results in the highest rate of crystallization and molecular alignment, impacting long-term stability and mechanical properties. A multivariate linear model incorporating crystallinity and molecular alignment predicts the material properties resulting from annealing under different conditions. Laser zone-drawing experiments reveal that polylactide fiber thinning under laser irradiation primarily occurs due to drawing rather than ablation. Steady-state …

Conduction Mechanism Switching From Coulomb Blockade To Classical Critical Percolation Behavior In Disordered Nanoparticle Array, Abhijeet Prasad, Jay Min Lim, Ravi Saraf

Department of Chemical and Biomolecular Engineering: Faculty Publications

Large, open-gate transistors made from metal nanoparticle arrays offer possibilities to build new electronic devices, such as sensors. A nanoparticle necklace network (N³) of Au particles from 300 K to cryogenic temperatures exhibit a nonohmic I–V_d behavior, I ≈ (V_d–V_T)^𝜻, where V_T is a conduction gap and 𝜻 is a constant critical exponent. The conduction gap in N³, made from disordered networks of 1D chains of 10 nm diameter Au particles exhibits room temperature (RT) gating. Although the I–V_d behavior at RT is identical to Coulomb blockade, …

The Discovery, Characterization, And Engineering Of Autolytic Enzymes As Antimicrobials, Jacob M. Furlon

Dartmouth College Ph.D Dissertations

In an age of rising levels of antibiotic resistance, we are quickly running out of tools to address some of the most virulent and widespread infectious bacteria. One group of enzymes that show significant potential for use as next-generation antibiotics are antimicrobial peptidoglycan hydrolases, often referred to as lysins. These enzymes are responsible for the breakdown of peptidoglycan within the bacterial cell wall, and, when exogenously applied, can result in dramatic destabilization of the cell wall leading to rapid lysis of the bacteria. While phage endolysins have been widely investigated as potential antimicrobials, the therapeutic potential of endogenous autolysins from …

Automatic Cardiac Mri Image Segmentation And Mesh Generation, Ziyuan Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Segmenting and reconstructing cardiac anatomical structures from magnetic resonance (MR) images is essential for the quantitative measurement and automatic diagnosis of cardiovascular diseases [1]. However, manual evaluation of the time-series cardiac MRI (CMRI) obtained during routine clinical care are laborious, inefficient, and tends to produce biased and non-reproducible results [2]. This thesis proposes an end-to-end pipeline for automatically segmenting short-axis (SAX) CMRI images and generating high-quality 2D and 3D meshes suitable for finite element analysis. The main advantage of our approach is that it can not only work as a stand-alone pipeline for the automatic CMR image segmentation and mesh …

The Effect Of Slow Strain Rate Tension And Cyclic Loading On Biodegradable Zn–2%Fe–0.8%Mn Alloy In A Simulated Physiological Environment, Lital Ben Tzion-Mottye, Adi Bahar, Tomer Ron, Galit Katarivas Levy, Jeremy Goldman, Dan Eliezer, Eli Aghion

Michigan Tech Publications

Zinc-based alloys have gained increased interest as biodegradable structural materials for medical applications due to their adequate biocompatibility, crucial roles in many physiological functions and attractive antibacterial properties. However, the major drawbacks of zinc alloys relate to their inadequate mechanical properties and tendency to provoke fibrous encapsulation due to relatively high standard potential. Based on the promising effect of Mn on properties of Zn-based alloys, the present study aimed at evaluating the suitability of Zn–2%Fe–0.8%Mn alloy as a potential biodegradable implant under in-vitro conditions. This evaluation focused on the passivation characteristics as determined by cyclic potentiodynamic polarization analysis, immersion test, …

Guar-Based Injectable Hydrogel For Drug Delivery And In Vitro Bone Cell Growth, Humandra Poudel, Ambar R. Rangumagar, Pooja Singh, Adeolu Oluremi, Nawab Ali, Fumiya Watanabe, Joseph Batta-Mpouma, Jin-Woo Kim, Ahona Ghosh, Anindya Ghosh

Chemistry & Biochemistry Faculty Publications and Presentations

Injectable hydrogels offer numerous advantages in various areas, which include tissue engineering and drug delivery because of their unique properties such as tunability, excellent carrier properties, and biocompatibility. These hydrogels can be administered with minimal invasiveness. In this study, we synthesized an injectable hydrogel by rehydrating lyophilized mixtures of guar adamantane (Guar-ADI) and poly-β-cyclodextrin (p-βCD) in a solution of phosphate-buffered saline (PBS) maintained at pH 7.4. The hydrogel was formed via host-guest interaction between modified guar (Guar-ADI), obtained by reacting guar gum with 1-adamantyl isocyanate (ADI) and p-βCD. Comprehensive characterization of all synthesized materials, including the hydrogel, was performed using …

Construction And Performance Optimization Of Bioconjugated Nanosensors For Early Detection Of Breast Cancer And Pro-Inflammatory Diseases, Pooja Gaikwad

Dissertations, Theses, and Capstone Projects

In recent years, nanosensors have emerged as a tool with strong potential in medical diagnostics. Single-walled carbon nanotube (SWCNT) based optical nanosensors have notably garnered interest due to the unique characteristics of their near-infrared fluorescence emission, including tissue transparency, photostability, and various chiralities with discrete absorption and fluorescence emission bands. Additionally, the optoelectronic properties of SWCNT are sensitive to the surrounding environment, which makes them suitable for in vitro and in vivo biosensing. Single-stranded (ss) DNA-wrapped SWCNTs have been reported as optical nanosensors for cancers and metabolic diseases. Breast cancer and cardiovascular diseases are the most common causes of death …

Contribution Of Implicit Memory To Adaptation Of Movement Extent During Reaching Against Unpredictable Spring-Like Loads: Insensitivity To Intentional Suppression Of Kinematic Performance, Devon D. Lantagne, Leigh A. Mrotek, James B. Hoelzle, Danny G. Thomas, Robert A. Scheidt

Psychology Faculty Research and Publications

We examined the extent to which intentionally underperforming a goal-directed reaching task impacts how memories of recent performance contribute to sensorimotor adaptation. Healthy human subjects performed computerized cognition testing and an assessment of sensorimotor adaptation, wherein they grasped the handle of a horizontal planar robot while making goal-directed out-and-back reaching movements. The robot exerted forces that resisted hand motion with a spring-like load that changed unpredictably between movements. The robotic test assessed how implicit and explicit memories of sensorimotor performance contribute to the compensation for the unpredictable changes in the hand-held load. After each movement, subjects were to recall and …

Bilateral Arm Movements Are Coordinated Via Task-Dependent Negotiations Between Independent And Codependent Control, But Not By A “Coupling” Control Policy, Nick M. Kitchen, Jisung Yuk, Andrzej Przybyla, Robert A. Scheidt, Robert L. Sainburg

Biomedical Engineering Faculty Research and Publications

Prior research has shown that coordination of bilateral arm movements might be attributed to either control policies that minimize performance and control costs regardless of bilateral symmetry or by control coupling, which activates bilaterally homologous muscles as a single unit to achieve symmetric performance. We hypothesize that independent bimanual control (movements of one arm are performed without influence on the other) and codependent bimanual control (two arms are constrained to move together with high spatiotemporal symmetry) are two extremes on a coordination spectrum that can be negotiated to meet infinite variations in task demands. To better understand and distinguish between …

Pine-Tree Enables Efficient Enrichment Of Prime-Edited Hpscs, Mary S. Jia, Christopher E. Nelson

Biomedical Engineering Faculty Publications and Presentations

Commentary

PINE-TREE enables efficient enrichment of prime-edited hPSCs

Bacterial Motion And Spread In Porous Environments, Yasser Almoteri

Dissertations

Micro-swimmers are ubiquitous in nature from soil and water to mammalian bodies and even many technological processes. Common known examples are microbes such as bacteria, micro-algae and micro-plankton, cells such as spermatozoa and organisms such as nematodes. These swimmers live and have evolved in multiplex environments and complex flows in the presence of other swimmers and types, inert particles and fibers, interfaces and non-trivial confinements and more. Understanding the locomotion and interactions of these individual micro-swimmers in such impure viscous fluids is crucial to understanding the emergent dynamics of such complex systems, and to further enabling us to control and …

Cell Encapsulation In Gelatin Methacryloyl Bioinks Impairs Microscale Diffusion Properties, Elvan Dogan, Christina Holshue, Anant Bhusal, Roshni Shukla, Amir K. Miri

Henry M. Rowan College of Engineering Departmental Research

Light-assisted bioprinted gelatin methacryloyl (GelMA) constructs have been used for cell-laden microtissues and organoids. GelMA can be loaded by desired cells, which can regulate the biophysical properties of bioprinted constructs. We study how the degree of methacrylation (MA degree), GelMA mass concentration, and cell density change mass transport properties. We introduce a fluorescent-microscopy-based method of biotransport testing with improved sensitivity compared to the traditional particle tracking methods. The diffusion capacity of GelMA with a higher MA significantly decreased compared to a lower MA. Opposed to a steady range of linear elastic moduli, the diffusion coefficient in GelMA varied when cell …

Validation Of A Biomechanical Injury And Disease Assessment Platform Applying An Inertial-Based Biosensor And Axis Vector Computation, Wangdo Kim, Emir A. Vela, Sean S. Kohles, Victor Huayamave

Publications

Inertial kinetics and kinematics have substantial influences on human biomechanical function. A new algorithm for Inertial Measurement Unit (IMU)-based motion tracking is presented in this work. The primary aims of this paper are to combine recent developments in improved biosensor technology with mainstream motion-tracking hardware to measure the overall performance of human movement based on joint axis-angle representations of limb rotation. This work describes an alternative approach to representing three-dimensional rotations using a normalized vector around which an identified joint angle defines the overall rotation, rather than a traditional Euler angle approach. Furthermore, IMUs allow for the direct measurement of …

Calculating The Difference In Stiffness Of Living T Cells Through Micropipette Aspiration, Minju Lee

McKelvey School of Engineering Graduate Student Theses & Dissertations

Cardiovascular disease (CVD) accounted for 17.9 million deaths in 2019, with fibrosis contributing to nearly a quarter of these fatalities [1,2]. Fibrosis, characterized by excessive connective tissue formation, has been strongly linked to T cells, essential components of the immune system. This study explores the mechanisms of T cell activation and the subsequent changes in biophysical properties like diameter, stiffness, and elasticity, aiming to develop therapeutic strategies for fibrosis-related diseases, including CVD. Utilizing the micropipette aspiration technique, we accurately assessed T cell stiffness and observed a change in bulk cell stiffness upon activation. The results demonstrated increased fluid-like behavior in …

Thermoresponsive Polymers With Lcst Transition: Synthesis, Characterization, And Their Impact On Biomedical Frontiers, Yichun Yuan, Konpal Raheja, Nathalie B. Milbrandt, Sophia Beilharz, Steffy Tene, Solomon Oshabaheebwa, Umut A. Gurkan, Anna Cristina S. Samia, Metin Karayilan

Faculty Scholarship

Advances in thermoresponsive materials have significantly impacted many biomedical fields. The unique behavior of reversible phase transition close to the physiological temperatures makes these types of materials a great candidate for a wide variety of biomedical applications including bioimaging, biosensing, injectables, smart surfaces, adhesives, biomanufacturing, and tissue engineering. Thermoresponsive behavior, mainly lower critical solution temperature (LCST) can be easily tuned by shifting the balance between hydrophobicity and hydrophilicity (e.g., by using comonomers or changing end groups) and modifying the molecular weight and architecture of the polymer. Hence, synthetic and characterization tools are critical in tailoring and precisely determining these properties. …

Enhancing Human Key Point Identification: A Comparative Study Of High-Resolution Vicon Dataset And Coco Dataset Using Bpnet, Bibash Lama

Masters Theses

Accurately identifying human key points is crucial for various applications, including activity recognition, pose estimation, and gait analysis. This study presents a high-resolution dataset created using the VICON motion capture system and three differently oriented 2D cameras, that can be used to train different neural networks for estimating the 2D key joint positions of the person from the 2D images or videos. The participants in the study included 25 healthy adults (17 males and 8 females) performing normal gait movements for about 2 to 3 seconds. The VICON system captured 3D ground truth data, while the three 2D cameras collected …

Hierarchical Based Classifcation Method Based On Fusion Ofgaussian Map Descriptors Foralzheimer Diagnosis Using T1‑Weighted Magnetic Resonance Imaging, Nourhan Zayed, Shereen E. Morsy, Inas A. Yassine

Mechanical Engineering

Alzheimer’s disease (AD) is considered one of the most spouting elderly diseases. In 2015, AD is reported the US’s sixth cause of death. Substantially, non-invasive imaging is widely employed to provide biomarkers supporting AD screening, diagnosis, and progression. In this study, Gaussian descriptors-based features are proposed to be efcient new biomarkers using Magnetic Resonance Imaging (MRI) T1-weighted images to diferentiate between Alzheimer’s disease (AD), Mild Cognitive Impairment (MCI), and Normal controls (NC). Several Gaussian map-based features are extracted such as Gaussian shape operator, Gaussian curvature, and mean curvature. The aforementioned features are then introduced to the Support Vector Machine (SVM). …

Engineering Multifunctional Adhesive Hydrogel Patches For Biomedical Applications, Aishik Chakraborty, Shana Alexander, Wei Luo, Narisse Al-Salam, Mia Van Oirschot, Sudhir H. Ranganath, Subrata Chakrabarti, Arghya Paul

Chemical and Biochemical Engineering Publications

Traditional patches, such as sticking plaster or acrylic adhesives used for over a hundred years, lack functionality. To address this issue of poor functionality, adhesive hydrogel patches have emerged as an efficient bioactive multifunctional alternative. Hydrogels are three-dimensional, water-swellable, and polymeric materials closely resembling the native tissue architecture. The physicochemical properties of hydrogels can be modified easily, allowing them to be suitable for various biomedical applications. Moreover, adhesive properties can be imparted to hydrogels through physicochemical manipulations, making them ideal candidates for supplementing or replacing traditional sticking plaster. As a result, sticky hydrogel patches are widely used for transdermal drug …

Don't Fear The Artificial Intelligence: A Systematic Review Of Machine Learning For Prostate Cancer Detection In Pathology, Aaryn Frewing, Alexander B. Gibson, Richard Robertson, Paul Urie, Dennis Della Corte

Faculty Publications

The adoption of whole slide image (WSI) scanners in clinical practice was accelerated by US Food and Drug Administration approval in 2017, which allowed primary pathologic diagnoses to be made on scanned images. Images in the digital domain allow the application of pathology artificial intelligence (AI), including clinical decision support with algorithms performing specific diagnoses.1,2 These algorithms, if trained properly, could go beyond the ability of human observation to detect and quantify features that are not recognizable by human perception.1,3,4