Digital Commons Network^™

Physical And Geometrical Modulation Of Human Fibroblast Behaviour, Sarah M. Brooks

Electronic Thesis and Dissertation Repository

This thesis investigates the impact of mechanical stimuli, specifically substratum topography and elastic modulus, on dermal and gingival fibroblast behaviour associated with scarring and regeneration. Scar formation presents a significant issue for implanted biomaterials often leading to device failure. Even though scar formation is a normal end point to adult human dermal wound healing, gingival wounds are capable of tissue regeneration or scarless wound healing. Understanding how these cells respond to environmental cues, including substratum topography and elastic modulus, is central to the development of novel biomaterials for stimulation of tissue regeneration. It was hypothesized that topographic features, with submicron …

Mechanical Evaluation Of Gyroid Structures To Combat Orthopaedic Implant Infections, Sydney Hitchon

Electronic Thesis and Dissertation Repository

Treatment of infected orthopaedic implants often require two separate surgeries to clear the infection and install a replacement implant. Current antimicrobial drug delivery methods are inefficient, and each additional surgery increases the physiologic burden on patients, with an increased risk of infection, decreased range of motion and longer recovery times. Porous orthopaedic implants, with adequate strength for permanent implantation and the ability to house and elude more efficient antibiotic delivery systems, could result in a single surgery to treat orthopaedic infections. Therefore, finite element models of porous gyroid structures at different porosities were developed and compared with experimental results. Discrepancies …

Biomechanical Investigation Of Complete And Partial Medial Collateral Ligament Injuries, Callahan Doughty

Electronic Thesis and Dissertation Repository

The medial collateral ligament (MCL) is composed of two major components: the deep MCL (dMCL) and superficial MCL (sMCL). Recent indications have raised questions as to the validity of previous descriptions of the MCL’s role in knee stability. Despite the relative likelihood of partial injuries to the sMCL, as opposed to complete tears, the impact of these injuries remains largely misunderstood. This thesis set out to (1) interpret the roles of the sMCL and dMCL; and (2) investigate the effect of partial sMCL injuries on knee stability.

A joint motion simulator was used to determine the role of the dMCL …

Early Biological Response Of Articular Cartilage To Hemiarthroplasty Wear, Debora Rossetti

Electronic Thesis and Dissertation Repository

Hemiarthroplasties typically result in accelerated wear of the preserved side of the joint, resulting in suboptimal clinical outcomes and limited longevity. This in vitro study investigated the effects of hemiarthroplasty implant curvature on the early biological response of articular cartilage measured by proteoglycan release, histology, and surface morphology. Cartilage from boar radiocarpal joints were worn by metal pins of varying radii of curvature (RoC) using a pin-on-plate wear simulator. Histology and proteoglycan assays showed no significant differences between RoC treatment groups, and proteoglycan assays showed increased proteoglycan release 72 hours after wear testing in worn cartilage specimens compared to control …

Investigation Of Cell Derived Nanoparticles For Drug Delivery And Osteogenic Differentiation Of Human Stem/Stromal Cells, Shruthi Polla Ravi

Electronic Thesis and Dissertation Repository

The successful repair of bone defects and injuries is enhanced by the delivery of osteoinductive factors, such as drugs, growth factors, and genetic material that can promote the osteogenic differentiation of stem/stromal cells into osteoblasts. Nanoparticle delivery systems are being studied to enable the sustained release of these factors but suffer from limitations such as cytotoxicity issues, poor loading capacity, and poor cellular uptake. In this project, we developed cell-derived nanoparticles (CDNs), a biomimetic nanoparticle delivery system with high drug loading efficiency, to deliver a glucocorticoid drug, dexamethasone (Dex), to promote the osteogenic differentiation of stem/stromal cells. The synthesized Dex-loaded …

Sol-Gel Derived Bioceramic Poly(Diethyl Fumarate – Co – Triethoxyvinylsilane) Composite, Aref Sleiman

Electronic Thesis and Dissertation Repository

Synthetic bone graft materials have become an increasingly popular choice for bone augmentation. Ceramic-based and polymer-based bone graft materials constitute the two main classes of synthetic bone graft materials. This study investigated the synthesis of novel bioactive composites for their potential use as bone graft biomaterials. Poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic class II organic/inorganic hybrid biomaterials were synthesized via a sol gel process. These biomaterials were then reacted with an ammonium phosphate solution to prepare their respective composites. For the first time, we successfully synthesized sol-gel derived bioceramic poly(diethyl fumarate-co-triethoxyvinylsilane) composites. In vitro bioactivity evaluation of poly(diethyl fumarate-co-triethoxyvinylsilane)/bioceramic composites in simulated body fluid …

Cost-Effective Non-Destructive Testing Of Biomedical Components Fabricated Using Additive Manufacturing, Santiago Fabian Cobos

Electronic Thesis and Dissertation Repository

Biocompatible titanium-alloys can be used to fabricate patient-specific medical components using additive manufacturing (AM). These novel components have the potential to improve clinical outcomes in various medical scenarios. However, AM introduces stability and repeatability concerns, which are potential roadblocks for its widespread use in the medical sector. Micro-CT imaging for non-destructive testing (NDT) is an effective solution for post-manufacturing quality control of these components. Unfortunately, current micro-CT NDT scanners require expensive infrastructure and hardware, which translates into prohibitively expensive routine NDT. Furthermore, the limited dynamic-range of these scanners can cause severe image artifacts that may compromise the diagnostic value of …

Catechol-Containing Copolymers As An Active Ingredient For Denture Adhesives, Vincent Ying Wun Kong

Electronic Thesis and Dissertation Repository

Moisture inside the mouth adds challenge to making denture adhesives formulations. Some formulations have zinc to enhance adhesion on wet skin despite knowing the health hazards. Inspired by mussel foot proteins’ catechol unit’s strong underwater adhesion, nine catechol-containing copolymers (P1A-P3C) were synthesized by free radical polymerization of 3,4-dimethoxystyrene (3,4- DMS) with different styrene derivatives followed by deprotection. P1A-P3C were used to make Fn(P)-C-PBS denture adhesive formulations which had suitable shear stresses around ≥ 5 kPa satisfying ISO 10873. In-situ NMR studies of free radical polymerization of 3,4 - DMS and styrene derivatives allowed computation of their reactivity ratios showing all …

In Vitro Analyses Of The Contributions Of The Hip Capsule To Joint Biomechanics, Emma Donnelly

Electronic Thesis and Dissertation Repository

Optimal management of the hip capsule during arthroscopic surgery has not been established. The impact of incisions made to the capsule during minimally invasive procedures on joint biomechanics, and whether repair provides any benefit, continue to be debated. The effectiveness of capsular repair to restore native kinematics may be insufficient. Therefore, a better understanding of joint behavior during various capsule conditions is needed. A new robotic system was used to analyze the effect of progressive capsulotomy incision and repairs on the behavior of a normal hip within range of motion (ROM) limits with respect to the intact joint. Complete repairs …

Development Of Hybrid Coating Materials To Improve The Success Of Titanium Implants, Zach Gouveia

Electronic Thesis and Dissertation Repository

While titanium (Ti) and its alloys have become ubiquitous within implantology as materials to restore or augment the function of human tissues, their success is plagued by complications associated with infection and aseptic implant loosening. These two risks account for the majority of implant failures in the clinic and limit the long-term success of titanium implants in vivo. Therefore, this thesis describes the development of robust multifunctional class II organic-inorganic hybrid coating materials for titanium implants that could be used to effectively target both complications, concurrently. During this master’s work, two different coating systems were examined. First, class II …

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 …

The Co-Delivery Of Syngeneic Adipose-Derived Stromal Cells And Macrophages On Decellularized Adipose Tissue Bioscaffolds For In Vivo Soft Tissue Regeneration, Hisham A. Kamoun

Electronic Thesis and Dissertation Repository

Decellularized adipose tissue (DAT) bioscaffolds are a promising platform for the delivery of pro-regenerative cell populations with the goal of promoting adipose tissue regeneration. The current study investigated the effects of seeding DAT bioscaffolds with syngeneic bone marrow-derived macrophages and/or adipose-derived stromal cells (ASCs) on in vivo soft tissue regeneration. Methods were established to derive the macrophages from MacGreen mice, which were dynamically seeded onto the DAT scaffolds alone or in combination with ASCs. Seeded and unseeded scaffolds were implanted subcutaneously into C57Bl/6 mice. At 2 and 4 weeks, cell infiltration, angiogenesis, and adipogenesis were analyzed through histology and immunohistochemistry. …

Quantifying The Outcomes Of A Virtual Reality (Vr)-Based Gamified Neck Rehabilitation, Shahan Salim

Electronic Thesis and Dissertation Repository

Neck pain is a major global public health concern and adds a significant financial burden to both the healthcare system as well as people suffering from it. Additionally, it presents measurement and evaluation challenges for clinicians as well as adherence challenges and treatment barriers for the patients. We have developed a virtual reality (VR)-based video game that can be used to capture outcomes that may aid in the assessment and treatment of neck pain. We investigated: (i) performance metrics of overall accuracy, accuracy based on movement difficulty, duration, and total envelope of movement; (ii) stability across sessions; (iii) accuracy across …

A Ph-Sensitive Delivery System For The Prevention Of Dental Caries Using Salivary Proteins, Yi Zhu

Electronic Thesis and Dissertation Repository

Dental caries remains one of the most common chronic diseases worldwide. Salivary proteins such as histatins have demonstrated biological functions directly related to tooth homeostasis and prevention of dental caries. However, histatins are susceptible to the high proteolytic activities in the oral environment. Therefore, pH-sensitive chitosan nanoparticles (CNs) have been proposed as potential carriers to target major oral diseases that occur under acidic conditions (e.g. dental caries and dental erosion). Four different types of chitosan polymers were investigated and the optimized CNs successfully loaded histatin 3 and released it selectively under acidic conditions. Through loading the survival time of histatin …

Design Of Tissue-Specific Cellular Microenvironments For Adipose-Derived Stromal Cell Culture And Delivery, Arthi Shridhar

Electronic Thesis and Dissertation Repository

The development of in vitro cell culture models that investigate tissue-specific effects of the extracellular matrix (ECM) on stem/progenitor cell lineage-commitment can contribute towards the design of improved cell delivery strategies. This thesis developed processing methods that conserved ECM bioactivity to generate well-characterized 2- and 3-D culture platforms that facilitated the evaluation of ECM composition on the adipogenic and osteogenic differentiation of human adipose-derived stromal cells (ASCs). Initial work compared α-amylase and pepsin digestion as methods to fabricate ECM coatings. The effects of enzyme processing and ECM composition were explored using human decellularized adipose tissue (DAT) and bovine tendon collagen …

Virtual Reality Simulation Of Glenoid Reaming Procedure, Mohammadreza Faieghi

Electronic Thesis and Dissertation Repository

Glenoid reaming is a bone machining operation in Total Shoulder Arthroplasty (TSA) in which the glenoid bone is resurfaced to make intimate contact with implant undersurface. While this step is crucial for the longevity of TSA, many surgeons find it technically challenging. With the recent advances in Virtual Reality (VR) simulations, it has become possible to realistically replicate complicated operations without any need for patients or cadavers, and at the same time, provide quantitative feedback to improve surgeons' psycho-motor skills. In light of these advantages, the current thesis intends to develop tools and methods required for construction of a VR …

The Development Of A Temporomandibular Force Simulator To Study Craniofacial Strain In-Vitro, Kenneth Kc Ip

Electronic Thesis and Dissertation Repository

An in-vitro musculoskeletal loading simulator was developed to replicate the internal forces of mastication, and then employed in a comparison of clinically relevant facial fracture repairs. Muscle forces are simulated by pneumatic pistons via 3D printed mounts that are reverse-engineered from CT scan to match muscle attachment sites, which are adhered to bone in order to simulate native stress distributions. Bite force and bone strain pattern of the craniofacial structure under load were measured using a force sensor and strain gauges respectively. In a series of five fresh-frozen cadaveric heads, it was found that strain patterns of the craniofacial structure …

The Effect Of Implant Girth And Implant Collar On The Degree Of Bone To Implant Contact And Bone Stresses In The Proximal Humerus, Stephanie Synnott

Electronic Thesis and Dissertation Repository

Stem design is a crucial element for the success of shoulder prostheses. Various components of stem design have been investigated; however, little research has been conducted on the effects of (1) implant girth and (2) an implant collar on load transfer. A generic implant model was designed and employed in a (FE) model to determine 3 outcome measures: changes in the degree of bone to implant contact (BIC), changes in cortical and trabecular bone stresses from the intact state, and changes in cortical and trabecular strain energy densities (SED). The variables examined were (1) implant girth (small, medium [generic base …

Fabrication And Modification Of Titania Nanotube Arrays For Harvesting Solar Energy And Drug Delivery Applications, Ahmed El Ruby Abdel Rahman Mohamed

Electronic Thesis and Dissertation Repository

The fast diminishing of fossil fuels in the near future, as well as the global warming caused by increasing greenhouse gases have motivated the urgent quest to develop advanced materials as cost-effective photoanodes for solar light harvesting and many other photocatalytic applications. Recently, titania nanotube arrays (TNTAs) fabricated by anodization process has attracted great interest due to their excellent properties such as: high surface area, vertically oriented, highly organized, one-dimensional, nanotubular structure, photoactivity, chemical stability and biocompatibility. This unique combination of excellent properties makes TNTAs an excellent photoanode for solar light harvesting. However, the relatively wide band gap energy of …

Ultra-High Field Strength Mr Image-Guided Robotic Needle Delivery Device For In-Bore Small Animal Interventions, Matthew J. Gravett

Electronic Thesis and Dissertation Repository

Current methods of accurate soft tissue injections in small animals are prone to many sources of error. Although efforts have been made to improve the accuracy of needle deliveries, none of the efforts have provided accurate soft tissue references. An MR image-guided robot was designed to function inside the bore of a 9.4T MR scanner to accurately deliver needles to locations within the mouse brain. The robot was designed to have no noticeable negative effects on the image quality and was localized in the MR images through the use of an MR image visible fiducial. The robot was mechanically calibrated …

Mechanical Properties Of Poly (Vinyl Alcohol) Based Blends And Composites, Nazanin Afghan

Electronic Thesis and Dissertation Repository

One of the most important product specifications in design of materials for different applications is to closely match desired mechanical properties of the target. The soft tissue could be very elastic such as blood vessels and skin, whereas others are soft and non-elastic such as fat tissue. Soft human tissue has a diverse structural component that give them the different feel, texture, shape, and mechanical properties.

Poly (vinyl alcohol) (PVA) as hydrophobic polymer has outstanding features such as very good physico-mechanical properties, nontoxicity and biocompatibility, and high swelling properties which makes them favorable for biomaterial and biomedical applications. By physically …

The Role Of Bone Sialoprotein In Periodontal Tissue Development And Bone Repair, Yohannes Soenjaya

Electronic Thesis and Dissertation Repository

Bone development and repair involve complex processes that include interaction between cells and their surrounding matrix. In the body, bone sialoprotein (BSP) expression is up-regulated at the onset of mineralization. BSP is a multifunctional acidic phosphoprotein with collagen-binding, hydroxyapatite nucleating, and integrin recognition (RGD sequence, which is important for cell-attachment and signaling) regions. Mice lacking BSP expression (Bsp^-/-), exhibit a bone phenotype with reductions in bone mineral density, bone length, osteoclast activation, and impaired bone healing. This thesis examined the role of BSP in tooth development and also its potential use as a therapeutic reagent for bone …

The Application Of The Ultrafine Technology In Improving The Biocompatibility And Osteo-Inductivity Of Dental Implants, Nicholas Y. Hou

Electronic Thesis and Dissertation Repository

Dental implants are very effective medical devices. However, although stable, the conventional titanium implants are not very bioactive which in some instances could reduce their efficacy. This thesis described the research progress of using polymeric ultrafine-particles with bioactive additives to enrich the surface of titanium substrate, thereby increasing the biocompatibility and osteo-inductivity of the biomaterial. During this doctoral project, three different types of polymers were examined, initially the conventional polyester, and later the novel epoxy as well as the epoxy/polyester hybrid polymers. Physical characterizations confirmed that all of the coating powders were ultrafine particles, and homogeneous surfaces were constructed from …

Bioactive Glass-Ceramic Coating Of Titanium Substrates By Alkaline Hydrothermal Process, Mohamed Gebril

Electronic Thesis and Dissertation Repository

Surface modification is a well-known approach to enhance the osseointegration of titanium dental implants. In this study, a novel hydrothermal method for coating titanium surfaces with bioactive glass was developed. Our method included sol-gel synthesis of bioactive glass, followed by hydrothermal coating of titanium under different NaOH concentrations. The surface properties of coated substrates were evaluated by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and surface profilometry. By varying the alkalinity of the hydrothermal process, different surface topographies, crystalline phases and chemistries could be obtained. Soaking the hydrothermally coated titanium substrates in simulated body fluid resulted in hydroxyapatite …

Force Sensing In Arthroscopic Instruments Using Fiber Bragg Gratings, Daniel S. Yurkewich

Electronic Thesis and Dissertation Repository

Minimally-invasive surgery has revolutionized many medical procedures; however, it also impedes the ability to feel the interaction between the surgical tool and the anatomical part being operated on. In order to address this problem, it is necessary to obtain accurate measurements of the interaction forces exerted on the surgical tools during surgery. These forces can then be manifested to the surgeon via a haptic device or presented visually (visual-force feedback). This thesis describes the use of a fiber optic device to measure and display to the surgeon interaction forces acting on an arthroscopic tool. The sensorization of the tool involves …

Engineering Periodontal Tissue Regeneration With The Use Of A Novel Periostin Electrospun Scaffold, Kendal I. Creber

Electronic Thesis and Dissertation Repository

Clinical therapies for the treatment of periodontitis are unable to reproducibly stimulate regeneration of the periodontium. We assessed the use of a novel electrospun type I collagen scaffold containing recombinant periostin to stimulate regeneration of the periodontal ligament (PDL) and bone. Human PDL cells demonstrated the ability to form a mineralized matrix in vitro and reduced osteogenic potential with increased donor age. In vitro analysis indicated scaffolds were biocompatible, however, periostin did not significantly influence adhesion or growth. In the healing of fenestration defects in rats, type I collagen scaffolds (with and without periostin) initially delayed cell infiltration and increased …

A New Generation Of Polymer/Ceramic Composite Biomaterials For Bone Regeneration, Mehrnaz Salarian

Electronic Thesis and Dissertation Repository

There is a substantial emerging interest for fundamental and applied research on the reinforcement of polymeric materials using nanotechnology. In the biomedical industry, development of novel bone cement composite materials with enhanced mechanical properties is of tremendous potential importance. The most universally used injectable bone cement is made of poly(methyl methacrylate) (PMMA); however, the major disadvantage of PMMA is its non-biodegradability. Polymers such as poly(propylene fumarate) (PPF) and polycaprolactone (PCL) are biodegradable, but suffer from a lack of mechanical properties. The aim of this research was to test the efficacy of these biodegradable polymers integrating nanotechnology for the development of …

The Effect Of Fixation Plate Length On Spinal Instability Following Anterior Cervical Plate Fixation For The Repair Of In Vitro Flexion-Distraction Injuries, Abdulaziz J. Al-Kuwari

Electronic Thesis and Dissertation Repository

Abstract:

The Effect of Fixation Plate Length on Spinal Instability Following Anterior Cervical Plate Fixation for the Repair of in Vitro Flexion-Distraction Injuries

Introduction: Anterior cervical decompression and fusion with a plate (ACDFP) is a commonly performed treatment following a traumatic injury to the subaxial cervical spine. The purpose of the presented work was to determine the biomechanical effect of plate length on cervical spine kinematic stability following ACDFP stabilization for a simulated traumatic injury.

Methods: Eleven fresh-frozen cadaveric C5-C6 and C6-C7 motion segments were examined in this study. To assess kinematics, flexibility testing was performed on each specimen …

Curcumin-Loaded Magnetic Nanoaggregates Conjugated With Folic Acid For Targeted Cancer Treatment, Melessa Salem

Electronic Thesis and Dissertation Repository

Cancer has been, and still remains, one of the most complicated diseases to treat. As a result of the side effects experienced from current cancer treatment methods, there has been a growing interest in the development of targeted drug delivery systems that can destroy cancer cells, but render healthy tissue unharmed. To address this challenge, magnetite nanoaggregates were synthesized through the precipitation of iron oxide in the presence of polymers, conjugated with folic acid for folate targeting, and loaded with curcumin for cancer treatment. The resulting magnetite nanoparticles were 10 – 20 nm in size and the aggregates formed varied …

Functional Co-Substituted Poly[(Amino Acid Ester)Phosphazene] Biomaterials, Amanda L. Baillargeon

Electronic Thesis and Dissertation Repository

The development of new and improved biomaterials is essential for tissue engineering and regenerative medicine applications. Amino acid-based polyphosphazenes are being explored as scaffold materials for tissue engineering applications due to their non-toxic degradation products and tunable material properties. This work focuses on the synthesis of non-functional and novel functional poly[(amino acid ester)phosphazene]s using a facile method of thermal ring opening polymerization followed by one-pot room temperature substitution. The family of polyphosphazenes developed in this work is based on L-alanine (PNEAs), L-phenylalanine (PNEFs), and L-methionine (PNEMs) with L-glutamic acid imparting the functionality. Characterization of these materials demonstrated that the one-pot …