Engineering Commons^™

Surgical Navigation In Image-Guided Transoral Robotic Surgery, Yuan Shi

Dartmouth College Ph.D Dissertations

Transoral robotic surgery (TORS) is a minimally invasive approach in treating head and neck cancers and has demonstrated improved surgical outcomes with reduced morbidity when compared to traditional open surgery. However, the lack of haptic feedback makes it more difficult to assess the tumor extent and locate critical structures (e.g., artery and nerves). In standard-of-care TORS, preoperative imaging is used as guidance; however, it becomes inaccurate intraoperatively: the patient’s neck is hyper-extended, surgical instruments are introduced, and soft tissues deform significantly. As a result, the surgeon is required to mentally predict intraoperative deformation, which can lead to bleeding complications and …

Advancements And Challenges In Additively Manufactured Functionally Graded Materials: A Comprehensive Review, Suhas Alkunte, Ismail Fidan, Vivekanand Naikwadi, Shamil Gudavasov, Mohammad Alshaikh Ali, Mushfig Mahmudov, Seymur Hasanov, Muralimohan Cheepu

Engineering Technology Faculty Publications

This paper thoroughly examines the advancements and challenges in the field of additively manufactured Functionally Graded Materials (FGMs). It delves into conceptual approaches for FGM design, various manufacturing techniques, and the materials employed in their fabrication using additive manufacturing (AM) technologies. This paper explores the applications of FGMs in diverse fields, including structural engineering, automotive, biomedical engineering, soft robotics, electronics, 4D printing, and metamaterials. Critical issues and challenges associated with FGMs are meticulously analyzed, addressing concerns related to production and performance. Moreover, this paper forecasts future trends in FGM development, highlighting potential impacts on diverse industries. The concluding section summarizes …

3d Printing With Photopolymerizable Polyester Resins For Resorbable Medical Device Applications, Mathew Murphy Stanford

All Dissertations

In the past decade, the healthcare industry has seen a significant increase in the use of additive manufacturing (AM or “3D printing”) with subsequent improvement in clinical outcomes.As an exceptional AM technology, vat-photopolymerization (VP), often called stereolithography, can create complex structures and has thus been adopted for a range of biomedical applications including surgical guides, temporary implants, and resorbable tissue scaffolds.However, limitations remain in the availability of photopolymerizable resin materials with appropriate mechanical performance, biodegradability, and biocompatibility for application to resorbable medical devices.

The objective of this work was to employ novel photopolymerizable polyester-based macromers in the development of resorbable …

Longitudinal Oxygen Imaging In 3d (Bio)Printed Models, Ryan Curtis O'Connell

Graduate Theses, Dissertations, and Problem Reports

Electron paramagnetic resonance (EPR), and its molecular imaging modality, is a powerful tool to noninvasively map various biological and chemical markers within objects of interest. Reliable data acquisition is a major impeding factor for longitudinal hands-off measurements. Measurements are especially challenging in biomedical applications, as live objects are not static. Frequent changes occur that require constant fine recalibration of the EPR detection system, called the resonator. To enable longitudinal imaging, a technology permitting automatic digital control of resonator coupling, tuning, and EPR data acquisition was developed. Automation was achieved through the utilization of a microcontroller and digital peripheral components such …

Conducting Polypyrrole Hydrogel Biomaterials For Drug Delivery And Cartilage Tissue Regeneration, Iryna Liubchak

Electronic Thesis and Dissertation Repository

Articular cartilage tissue has limited capacity for self-regeneration leading to challenges in the treatment of joint injuries and diseases such as osteoarthritis. The tissue engineering approach combines biomaterials, cells and bioactive molecules to provide a long-term and stable cartilage repair. In the following work, electroactive polymer polypyrrole~(PPy) was incorporated into the synthetic hydrogel to enhance the mechanical properties of the material for cartilage applications. PPy was loaded with drug compound and the \emph{on demand} drug release was demonstrated. The composite PPy hydrogel was 3D printed using stereolithography to create a porous tissue engineering scaffold. Biocompatibility and cell adhesion to the …

A Novel Electroconductive Nanofibrous Scaffold For Bone Regeneration, Mitchell Kenter

Medical Engineering Theses

The goal of this study was to develop a biodegradable and conductive scaffold to mimic the piezoelectric properties of bone and the architecture of the extracellular matrix. Poly(3,4- ethylenedioxythiophene) (PEDOT) is a conductive polymer of great interest in tissue engineering due to excellent electrical stability and biocompatibility. To enhance its conductivity, dopants such as dimethyl sulfoxide (DMSO) can be added. Engineered graphene oxide (GO) can also be introduced as oxidant to enhance conductivity and mechanical properties. PEDOT nanocomposites were synthesized by oxidative polymerization of 3, 4-Etylenedioxythiophene monomer (EDOT) in the presence of GO, DMSO, ferric chloride and various solvents. The …

Integrated Direct Air Capture And Oxidative Dehydrogenation Of Propane With Co2 At Isothermal Conditions, Shane Lawson, Khaled Baamran, Kyle Newport, Turki Alghamadi, Gary Jacobs, Fateme Rezaei, Ali A. Rownaghi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Developing routes of utilizing CO₂ emissions is important for long-term environmental preservation, as storing such emissions underground will eventually become unsustainable. One way of utilizing CO₂ emissions is as a light-oxidant feedstock for oxidative dehydrogenation of propane (ODHP) to propylene. However, the adsorption and reaction steps typically occur at widely different temperatures, meaning that the thermal gradients – and by extension process energy requirements – are often unreasonably high. In recent years, dual-functional materials (DFMs) – i.e., materials comprised of a high temperature adsorbent phase alongside a heterogeneous catalyst – have been employed for combined CO₂ adsorption …

A Highly Conductive, Flexible, And 3d-Printable Carbon Nanotube-Elastomer Ink For Additive Bio-Manufacturing, Andy Shar, Phillip Glass, Daeha Joung Ph.D.

Undergraduate Research Posters

The synthesis of a highly conductive, flexible, 3D-printable, and biocompatible ink has been of great interest in the field of bio-based additive manufacturing. Various applications include ultra-sensitive, microscale tactile sensors, patient-customizable scaffolds for cardiac and nerve tissue regeneration, and flexible electrocardiogram (ECG) electrodes. Here, a novel elastomeric carbon nanocomposite is presented consisting of amino-functionalized carbon nanotubes (CNT-NH₂) homogenously dispersed in a one-part room-temperature vulcanizing (RTV) silicone matrix. The use of acetone as a swelling solvent aids in electrical percolation through the elastomer matrix. CNT-NH₂ ratios can be tuned to fit various needs; higher tensile strength is favored …

3d Printed Polypyrrole Scaffolds For Ph Dependent Drug Delivery With Applications In Bone Regeneration, Matthew T. Lawrence

Electronic Thesis and Dissertation Repository

Areas of large bone loss are typically healed using autologous bone grafts, seen as the gold standard of care. These materials have a complication rate of 10–40% during harvesting and are limited by the quantity available; therefore the use of 3D printed polymer scaffolds as bone graft alternatives are proposed. Polypyrrole (PPy) is a biocompatible electroactive polymer that has metal-like electrical properties that can be harnessed to hold and release charged drug molecules, triggered by a change in pH. pH fluctuations are seen inside the human body in areas of bone regrowth, which would act as the triggering mechanism for …

Flow Visualization Of Bolus Microcapsule Delivery Through 3d Printed Microneedles, Sophie Quisling, Leana Vestal, Alexis Enstrom

Bioengineering Senior Theses

Microneedle arrays are an emerging technology that offers a novel drug delivery system to treat a variety of skin wounds and diseases. The needles deliver therapeutics to the epidermis layer of the skin and therefore establish advantageous qualities over the standard hypodermic needle as they are non-invasive, efficient in biologic absorption, and can be self-administered. This project investigates a custom 3D-printed hollow microneedle device created by a Santa Clara University Senior Design team in 2018 for microencapsulated cell extrusion to be applied for accelerated wound healing. The goal of our project is to operate in the therapeutic range for flowrate …

3d Printable And Computational Models Of The Bone Marrow Mechanical Environment, Alexander Regner

Boise State University Theses and Dissertations

Aged individuals and astronauts experience bone loss despite rigorous physical activity. Bone mechanoresponse is in part regulated by mesenchymal stem cells (MSCs). We reported that daily low intensity vibration (LIV) restores MSC proliferation in senescence and simulated microgravity models, suggesting reduced mechanical signal delivery to MSCs likely contributes to declining bone mechanoresponse. To this end, we have developed a 3D bone marrow analog which controls trabecular geometry, marrow mechanics and external stimuli.

Finite element (FE) models of hydrogels, representing bone marrow, were generated using instantaneous compression (1000% strain/s, 20% strain) and relaxation experiments (100s) of both gelatin and hyaluronin-based hydrogels. …

Quantifying Mafenide Release From 3d Printed Phenylalanine-Coumarin Copolyester Scaffolds, Jacob Seeh

Williams Honors College, Honors Research Projects

This project addressed burn wound healing through controlled release of the antibacterial drug mafenide encapsulated by a copolyster into 3D printed scaffolds. Scaffolds were printed at 25^oC and 0.77-1 bar in a cross-hatch pattern with uniform thickness, distance between parallel layers, and diameter then photo-crosslinked. The number of scaffolds available for testing was limited by the amount of polymer that could be synthesized. A high-performance liquid chromatography method was developed specifically for this experiment and used to determine daily release of mafenide from the scaffold into a 2-mL phosphate buffer solution. During the first 24 hours a large …

Development Of Novel Inks And Approaches For Printing Tissues And Organs, Shen Ji

Dissertations

Tissue engineering is a multidisciplinary field that investigates and develops new methods to repair, regenerate and replace damaged tissues and organs, or to develop biomaterial platforms as in vitro models. Tissue engineering approaches require the fabrication of scaffolds using biomaterials or fabrication of living tissues using cells. As the demands of customized, implantable tissue/organs are increasing and becoming more urgent, conventional scaffold fabrication approaches are difficult to meet the requirements, especially for complex large-scale tissue fabrication. In this regard, three-dimensional (3D) printing attracted more interest over the past decades due to its unrivaled ability to fabricate highly customized tissues or …

In The Pursuit Of Assistance: A Team's Desire To Not Let A Congenital Amputation Get In A Young Boy's Way, Carl Russell Iii, Gavin Loucks, Kirsten Wozniak

Purdue Journal of Service-Learning and International Engagement

EPICS is a service-learning design program run through Purdue University. It strives to teach students design skills through providing for individuals, communities, and organizations in the surrounding area while mirroring engineering industry standards. BME (Biomedical Engineering) is a team within EPICS that strives to serve community partners through biomedical applications. William Sevick is an elementary school student with a congenital arm amputation. William and his family have been working with the BME team for the past three years designing assistive devices with the purpose of improving his actions in daily life such as eating, playing games, and riding his bike.

Metal Additive Manufacturing For Fixed Dental Prostheses, Mai El Najjar

Electronic Thesis and Dissertation Repository

The use of additive manufacturing (AM) in dentistry has gained momentum in recent years. However, high initial costs and uncertainty surrounding the quality of AM products are considered barriers to their use. This research compared dental substructures fabricated by AM versus conventional casting and milling.

Cobalt-chromium alloy rectangular bars and three-unit bridge substructures were fabricated by AM, casting or milling. Bars manufactured by AM exhibited superior flexural strength, shear bond strength of porcelain coating, and Vickers hardness. Bridge substructures fabricated by AM showed similar flexural stiffness to cast, similar flexural loads at failure to milled and cast, and overall accuracy …

Bionic Hand Team, Christopher T. Rossiter, David J. Bogacz, Carly J. Ulrich

Scholars Symposium

The project goal is to design a low cost prosthetic hand controlled by a PIC18F25K22 microcontroller that will allow the user to perform simple tasks that require a greater dexterity than what a mechanical prosthetic can deliver. The digits of the prosthetic will be contracted or relaxed using electromyographic signals measured by electrodes on a single muscle group. Grip settings, which define the open and closed position for each digit, are used for the control of the hand. This allows common actions, such as grabbing a door handle or pencil, to be accomplished with readings from one muscle group instead …

Left Atrial Appendage Printing Process, Areli Reyes, Brandon James Mukai, Mia Noelle Von Knorring

Biomedical Engineering

The left atrial appendage senior design team aims to assist in closing off the left atrial appendage that is susceptible to coagulation due to non-valvular atrial fibrillation. Coagulation in the left atrial appendage (LAA) can be life threatening as it can lead to a stroke. Dr. Chris Porterfield performs a procedure that uses the Boston Scientific Watchman to close the appendage. He finds that sizing the Watchman properly is difficult with limited visuals from live CT scans. He proposed converting the CT scans into a 3D printed model of the left atrial appendage and left atrium so he can visually …

Titanium Nitride Nanotube Electrodes Used In Neural Signal Recording Application And Neurotransmitter Detection, Gui Chen

Wayne State University Dissertations

Electrode probes are devices widely used for stimulating and recording neural cell signals in the neuroscience field, which can convert the ion potential generated by electrochemical activities into an electronic potential that can be measured by the external instrument systems. A stable neural interface that effectively communicates with the nervous system via electrode is much important for the robust recording and the long-term monitoring of the activity of the neural signals. These probes are designed to minimize tissue damage for superior signal quality. Each probe’s mechanical, geometric, and electrical characteristics are precise and highly reproducible for consistent, high-quality results. There …

Binder Saturation, Layer Thickness, Drying Time And Their Effects On Dimensional Tolerance And Density Of Cobalt Chrome - Tricalcium Phosphate Biocomposite, John Ruprecht

All Graduate Theses, Dissertations, and Other Capstone Projects

Traditional metals such as stainless steel, titanium and cobalt chrome are used in biomedical applications (implants, scaffolds, etc.) but suffer from issues such as osseointegration and compatibility with existing bone. One way to improve traditional biomaterials is to incorporate ceramics with these metals so that their mechanical properties can be similar to cortical bones. Tricalcium phosphate is such a ceramic with properties such that it can be used in the human body. This research explores the use of the Binder Jetting based additive manufacturing process to create a novel biocomposite made of cobalt chrome and tricalcium phosphate. Experiments were conducted …

Application Of Halloysite Nanotubes In Bone Disease Remediation And Bone Regeneration, Yangyang Luo

Doctoral Dissertations

Customized patient therapy has been a major research focus in recent years. There are two research fields that have made a significant contribution to realizing individualized-based treatment: targeted drug delivery and three-dimensional (3D) printing technology. With benefit from the advances in nanotechnology and biomaterial science, various drug delivery systems have been established to provide precise control of therapeutic agents release in time and space. The emergence of three-dimensional (3D) printing technology enables the fabrication of complicated structures that effectively mimic native tissues and makes it possible to print patient-specific implants. My dissertation research used a clay nanoparticle, halloysite, to develop …

Application Of Micro-Scale 3d Printing In Pharmaceutics, Andrew Kjar, Yu Huang

Biological Engineering Faculty Publications

3D printing, as one of the most rapidly-evolving fabrication technologies, has released a cascade of innovation in the last two decades. In the pharmaceutical field, the integration of 3D printing technology has offered unique advantages, especially at the micro-scale. When printed at a micro-scale, materials and devices can provide nuanced solutions to controlled release, minimally invasive delivery, high-precision targeting, biomimetic models for drug discovery and development, and future opportunities for personalized medicine. This review aims to cover the recent advances in this area. First, the 3D printing techniques are introduced with respect to the technical parameters and features that are …

Improving 3d Printed Prosthetics With Sensors And Motors, Rachel Zarin

Honors Projects

A 3D printed hand and arm prosthetic was created from the idea of adding bionic elements while keeping the cost low. It was designed based on existing models, desired functions, and materials available. A tilt sensor keeps the hand level, two motors move the wrist in two different directions, a limit switch signals the fingers to open and close, and another motor helps open and close the fingers. All sensors and motors were built on a circuit board, programmed using an Arduino, and powered by a battery. Other supporting materials include metal brackets, screws, guitar strings, elastic bands, small clamps, …

Fabrication And Characterization Of Collagen-Polypyrrole Constructs Using Direct-Ink Write Additive Manufacturing, Rooshan Arshad

Electronic Thesis and Dissertation Repository

Current efforts in the tissue engineering field are being directed towards the creation of platforms which will facilitate in instructing cells towards biologically relevant outcomes such as stem cell differentiation and disease pathophysiology. Traditional fabrication methods serve as a limiting factor for the production of such platforms as they lack feature and geometric complexity. Additive Manufacturing (AM) offers advantage over said methods by affording designers creative freedom and great control over printed constructs. Such constructs can then be used to create appropriate models for study- ing a plethora of tissues and structures. An AM methodology for Direct-Ink Write (DIW) printing …

3d Printing A Microfluidic Chip Capable Of Droplet Emulsion Using Ninjaflex Filament, Robert Andrews

Mechanical Engineering Undergraduate Honors Theses

This paper details an investigation into methods and designs of 3D printing a microfluidic system capable of droplet emulsion using NinjaFlex filament. The specific field in which this paper’s experiment is rooted is dubbed “BioMEMS,” short for bio microelectromechanical systems. One prominent research area in BioMEMS is developing a “lab on a chip.” Essentially, the goal is to miniaturize common lab processes to the micro scale, rendering it possible to include these processes in a small chip. Reducing necessary sample sizes, shortening the reaction times of lab processes, and increasing mobility of lab processes can all be realized through microfluidic …

Design And Evaluation Of A 3d Printed Filar Micrometer, Emily M. Rull

ELAIA

Background Double stars are celestial objects that allow for calculating the mass of stars by assessing their orbits. Stellar mass affects every current model of stellar evolution, but the most accurate double star orbits can take decades to record. Due to the long-term nature of such observations and lack of groundbreaking research in double star studies, professional astronomers are no longer focused on making these measurements, so amateur astronomers can pick up where professionals have left off. Amateurs can only do this if they can get the equipment that they need at prices they can afford. A personally-manufactured filar micrometer …

Efficacy Of Eluted Antibiotics In 3d Printed Orthopaedic Implants, Mohammed Mehdi Benmassaoud

Theses and Dissertations

Costs associated with musculoskeletal diseases in the United States account for 5.7 % of the Gross Domestic Product (GDP) [1]. As such, there is a need to pursue new ideas in orthopaedic implants that can decrease cost and improve patient care. In the recent years, 3D printing using Fused Deposition Modeling (FDM) or Stereolithography (SLA) has opened several exciting possibilities to create orthopaedic implants. Such implants can be engineered to release antibiotics in a controlled manner either by infusing the drug into the material during manufacturing or by using built-in design features such as micro-channels and reservoirs [2]. The use …

Three-Dimensional (3d) Printed Microneedles For Microencapsulated Cell Extrusion, Chantell Farias, Roman Lyman, Cecilia Hemingway, Huong Chau, Anne Mahacek, Evangelia Bouzos, Maryam Mobed-Miremadi

Bioengineering

Cell-hydrogel based therapies offer great promise for wound healing. The specific aim of this study was to assess the viability of human hepatocellular carcinoma (HepG2) cells immobilized in atomized alginate capsules (3.5% (w/v) alginate, d = 225 µm ± 24.5 µm) post-extrusion through a three-dimensional (3D) printed methacrylate-based custom hollow microneedle assembly (circular array of 13 conical frusta) fabricated using stereolithography. With a jetting reliability of 80%, the solvent-sterilized device with a root mean square roughness of 158 nm at the extrusion nozzle tip (d = 325 μm) was operated at a flowrate of 12 mL/min. There was no significant …

Three Professions Come Together For An Interdisciplinary Approach To 3d Printing: Occupational Therapy, Biomedical Engineering, And Medical Librarianship, Joan Wagner, Laurel Scheinfeld, Blanche Leeman, Keith Pardini, Jamie Saragossi, Katie Flood

Library Faculty Publications

Background: Although many libraries have offered 3D printing as a service or available technology, there is a lack of information on course-integrated programs for 3D printing in which the library played a primary role. Therefore, librarians at the Touro College School of Health Sciences began exploring 3D printing for inclusion in the occupational and physical therapy curriculum. Case Presentation: The goal of this project was to educate occupational and physical therapy students and faculty about the potential applications of 3D printing in health care and provide hands-on experience, while increasing collaboration between librarians and faculty. Students’ tasks included designing and …

Developmental Steps For A Functional Three-Dimensional Cell Culture System For The Study Of Asymmetrical Division Of Neural Stem Cells, Martina Zamponi

Biomedical Engineering Theses & Dissertations

Stem cells are a cell type present during and following development, which possess self- renewal properties, as well as the ability to differentiate into specific cells. Asymmetrical division is the cellular process that allows stem cells to produce one differentiated and one un-differentiated daughter cell during the same mitotic event. Insights in the molecular mechanisms of such process are minimal, due to the absence of effective methods for its targeted study. Currently, traditional methods of investigation include monolayer cell culture and animal models. The first poses structural limitations to the accurate representation of human tissue and cell structures, while animal …

Bones Reborn: 3d Printing Offers Amazing Options For Traumatic Bone Loss, Clem Boyd

Staff Publications

No abstract provided.