Biomedical Engineering and Bioengineering Commons^™

When 1 + 1 > 2: Nanostructured Composites For Hard Tissue Engineering Applications, Vuk Uskoković

Pharmacy Faculty Articles and Research

Multicomponent, synergistic and multifunctional nanostructures have taken over the spotlight in the realm of biomedical nanotechnologies. The most prospective materials for bone regeneration today are almost exclusively composites comprising two or more components that compensate for the shortcomings of each one of them alone. This is quite natural in view of the fact that all hard tissues in the human body, except perhaps the tooth enamel, are composite nanostructures. This review article highlights some of the most prospective breakthroughs made in this research direction, with the hard tissues in main focus being those comprising bone, tooth cementum, dentin and enamel. …

Compression Transmission Collar For Fastening, Patrick Atkinson, David Lecronier

Mechanical Engineering Patents

A compression transmission collar apparatus (20) for implantation into a bone (22) with a hole (28) having a hole wall (32) comprising an intramedullary nail (34) defining a bore (40) and a threaded fastener (42) and a compression transmission collar (58) including an exterior face (64) and a top edge (60) and a bottom edge (62) and a first end (70) intersecting the top edge (60) at an acute angle and the bottom edge …

A Finite Element Analysis On The Viscoelasticity Of Postmenopausal Compact Bone Utilizing A Complex Collagen D-Spacing Model, Austin C. Cummings

Master's Theses

The nanoscale dimension known as D-spacing describes the staggering of collagen molecules, which are fundamental to the biphasic makeup of bone tissue. This dimension was long assumed to be constant, but recent studies have shown that the periodicity of collagen is variable. Given that the arrangement of collagen molecules is closely related to the degree of bone mineralization, recent studies have begun to look at D-spacing as a potential factor in the ongoing effort to battle postmenopausal osteoporosis. The theoretical models presented by previous studies have only opted to model a single collagen-hydroxyapatite period, so the creation of an intricate …

Piezoelectric Scaffolds For Osteochondral Defect Repair, Sita Mahalakshmi Damaraju

Dissertations

Osteoarthritis is one of the most prevalent causes of disability affecting nearly 27 million Americans. Osteoarthritis is caused when extensive damage occurs to the articular cartilage later spreading to the underlying subchondral bone, resulting in osteochondral defects. The current clinical therapies aim at regenerating the hyaline cartilage, but instead fibrocartilage forms at the osteochondral defect site, which is inferior in structure and function and fails to integrate with the surrounding tissue. A biomimetic scaffold, which can provide cues similar to the native extracellular matrix, may facilitate osteochondral defect repair. Articular cartilage and bone extracellular matrix have been shown to produce …

Finite Element Analysis Of The Application Of Ultrasound-Generated Acoustic Radiation Force To Biomaterials, Nicole J. Piscopo

Honors Scholar Theses

While most bone fractures can heal simply by being stabilized, others can take a longer time to rejoin or they could fail to merge back together completely. Numerous studies have shown the positive effects that ultrasonic therapy have had on delayed-union and non-union bone fracture repair but little is known as to what specific biological mechanisms are at play. Ultrasound may be a valuable tool for bone tissue regeneration at these fracture sites using a tissue engineering approach, however, more must be understood about its impact on stimulating tissues to heal before this can be a reality. For that reason, …

A Local, Sustained Delivery System For Zoledronic Acid And Rankl-Inhibitory Antibody As A Potential Treatment For Metastatic Bone Disease, Rohith Jayaram

Theses and Dissertations--Biomedical Engineering

Cancerous solid tumors can migrate and lead to metastatic bone disease. Drugs prescribed to reduce bone resorption from metastasis, such as zoledronic acid and the RANKL-inhibitory antibody Denosumab, cause side effects such as osteonecrosis of the jaw when delivered systemically. This project used two biocompatible materials, acrylic bone cement (PMMA) and poly(lactic-co-glycolic acid) (PLGA), to incorporate and sustain release of anti-resorptive agents. Results showed similar mechanical properties for acrylic bone cements loaded up to 6.6% drug by weight. Results showed sustained zoledronic acid release for 8 weeks from both systems, with PMMA releasing up to 22% of loaded drug and …

Human Hair Keratin Protein, Hair Fibers And Hydroxyapatite (Ha) Composite Scaffold For Bone Tissue Regeneration, Samuel Siyum

ETD Archive

The field of tissue engineering aims at promoting the regeneration of tissues or replacement of failing or malfunctioning tissue by means of combining a scaffold material, adequate cells and bioactive molecules. Different materials have been proposed for use as three-dimensional porous scaffolds for bone tissue engineering procedures. Among them, polymers of natural origin are one of the most attractive options mainly due to their similarities with the extracellular matrix (ECM), chemical versatility as well as typically good biological performance. In this study, two biocompatible composite scaffolds were developed from natural polymer by tissue engineering approach and tested in vitro. The …

The Effects Of Variation In Collagen D-Spacing On Compact Bone Viscoelasticity: A Finite Element Analysis, Miguel A. Mendoza

Master's Theses

The D-spacing that is characteristic of collagen and its structural arrangement was previously thought to be a constant value. Much research is revealing that it is actually a distribution of values in biological tissues. Recent ovine experimentation has also shown that the D-spacing distribution is significantly altered following estrogen depletion. While ewes contain some major biological differences between their human counterparts, they are an economical and robust large animal model for postmenopausal osteoporosis. So, the exploration of the possible implications that D-spacing has on the mechanical properties of the whole bone utilizing animal models and computational methods is warranted. Six …

Modeling The Zimmer Fitmore And Ml Taper Implantation, Tyler Kazuo Franklin

Master's Theses

With more young adults requiring total hip

arthroplasties the need for bone saving implants becomes

more important. The Zimmer Fitmore is a new bone saving

implant that utilizes an implantation technique that

reduces the damage to the muscle tissue allowing for

patients to have a short recovery time as well as a new

design that allows it to rest on the medial cortex. There

has been anecdotal evidence that this device leads to early

revision within six months of implantation due to failures

occurring in the medial cortex. The main goal of this

study was to computationally model the Zimmer …

Easily Implantable And Stable Nail-Fastener For Skeletal Fixation And Method, Patrick Atkinson, David Lecronier

Mechanical Engineering Patents

An intramedullary nail (20) defining a bore (34) is inserted into a medullary canal (26) of a bone (24). A threaded fastener (22) has a compression portion (48) presenting a compression portion diameter (D) and a threaded portion (50) present ing a threaded portion diameter (D). The fastener (22) extends through a near cortex hole (40) and/or a far cortex hole (42), and the threaded portion (22) threadedly engages the bore (34). A compression transmission device (54) is disposed between a head (44) of the fastener (22) and the intramedullary nail (20) for transmitting the compressional load of the threaded …

Bone Properties By Nanoindentation In Mild And Severe Osteogenesis Imperfecta, Carolyne Albert, John Jameson, Jeffrey M. Toth, Peter Smith, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background

Osteogenesis imperfecta is a heterogeneous genetic disorder characterized by bone fragility. Previous research suggests that impaired collagen network and abnormal mineralization affect bone tissue properties, however, little data is yet available to describe bone material properties in individuals with this disorder. Bone material properties have not been characterized in individuals with the most common form of osteogenesis imperfecta, type I.

Methods

Bone tissue elastic modulus and hardness were measured by nanoindentation in eleven osteotomy specimens that were harvested from children with osteogenesis imperfecta during routine surgeries. These properties were compared between osteogenesis imperfecta types I (mild, n = …

Compression Transmission Collar For Fastening, Patrick Atkinson

Mechanical Engineering Patents

A compression transmission collar apparatus (20) for implantation into a bone (22) with a hole (28) having a hole wall (32) comprising an intramedullary nail (34) defining a bore (40) and a threaded fastener (42) and a compression transmission collar (58) including an exterior face (64) and a top edge (60) and a bottom edge (62) and a first end (70) intersecting the top edge (60) at an acute angle (α₁) and …

Easily Implantable And Stable Nail-Fastener For Skeletal Fixation And Method, Patrick Atkinson, David Lecronier

Mechanical Engineering Patents

An intramedullary nail (20) for insertion into the medullary canal (26) in a bone (24) surrounded by the cortex (28) and defines a bore (34) extending transverse to the intramedullary nail (20). A threaded fastener (22) extends along a fastener axis (A) and has a compression portion (48) having a compression portion diameter (DCP), and a threaded portion (50) having a threaded portion diameter (DTP) extending through a near cortex hole (40) and a far cortex hole (42), both holes (40, 42) radially overlapping the bore (34) and the threaded portion diameter (DTP) threadedly engaging the bore (34). A compression …

Design And Validation Of Bending Test Method For Characterization Of Miniature Pediatric Cortical Bone Specimens, Carolyne Albert, John Jameson, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Osteogenesis imperfecta is a genetic disorder of bone fragility; however, the effects of this disorder on bone material properties are not well understood. No study has yet measured bone material strength in humans with osteogenesis imperfecta. Small bone specimens are often extracted during routine fracture surgeries in children with osteogenesis imperfecta. These specimens could provide valuable insight into the effects of osteogenesis imperfecta on bone material strength; however, their small size poses a challenge to their mechanical characterization. In this study, a validated miniature three-point bending test is described that enables measurement of the flexural material properties of pediatric cortical …

Esem Analysis Of Mice Femurs With Varying Sost Levels, Patrick K. Mcclay

Biomedical Engineering

This project’s goal was to analyze the properties of the cortical femur on 100 mice bones from Lawrence Livermore National Laboratory. Analysis was limited to imaging which determined the ratio of bone volume to total volume (BV/TV) and osteocyte lacunae density. Mice were altered to knock out their SOST gene: a negative regulator of bone formation. Twelve groups were created to differentiate their treatment, duration, and phenotype. Transgenic (TG) mice had an overexpression of the SOST gene: they carried a bacterial artificial chromosome. Mice with limb defects (DEF) were the offspring of two TG mice and carried twice the amount …

An Empirical Method For Correcting The Detector Spectral Response In Energy-Resolved Ct, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Energy-resolving photon-counting detectors have the potential for improved material decomposition compared to dual-kVp approaches. However, material decomposition accuracy is limited by the nonideal spectral response of the detectors. This work proposes an empirical method for correcting the nonideal spectral response, including spectrum-tailing effects. Unlike previous correction methods which relied on synchrotron measurements, the proposed method can be performed on the scanner. The proposed method estimates a spectral-response matrix by performing x-ray projection measurements through a range of known thicknesses of two or more calibration materials. Once estimated, the spectral-response matrix is incorporated into conventional material decomposition algorithms. A simulation study …

Bone Tissue Quality Determination Of Mice Through A Novel Reference Point Indentation Technique, Matin Lendhey

Dissertations and Theses

"Bone strength deteriorates with age; which increases the susceptibility to fracture. Current clinical techniques for the estimation of bone strength are largely Bone Mineral Density (BMD) based. However, toughness, which is the ability to resist crack growth, plays a critical role in bones‟ fracture resistance. Traditionally, toughness measurements involve large samples, obviating their use clinically. Recent data suggest that a reference point indentation approach provides a novel, localized measure of toughness from whole bones. In the current research, we evaluated the sensitivity of this method to discriminate small known differences in fracture toughness that exist between inbred mouse strains with …

Effects Of Estrogen Loss On The Vascular Porosity In Rat Cortical Bone, Jessica D Levy

Dissertations and Theses

"Osteoporosis is a skeletal disease that currently affects 10 million Americans, and is characterized by low bone mass and increased skeletal fragility (National Osteoporosis Foundation, 2011). Estrogen loss, which begins during menopause, is the leading cause of osteoporosis in women. Recent research has focused on changes in cortical bone microporosity due to estrogen loss, which is important for bone health; load-induced interstitial fluid flow within the lacunar-canalicular porosity surrounding osteocytes is thought to play an important role in bone maintenance, while the vascular porosity provides a pressure relaxation mechanism for the fluid flow in the lacunar-canalicular porosity. Recent high-resolution micro-CT …

The Development And Validation Of A Finite Element Model Of A Canine Rib For Use With A Bone Remodeling Algorithm., Scott J. Sylliaasen

Master's Theses

Studies are currently being performed to determine the effects of bisphosphonate treatments on the structure and density of bone tissue. One of the pathways for gaining a better understanding of the effects of this and other treatments involves creating a computer simulation. Theory suggests that bone tissue structure and density are directly related to the manner in which the tissue is loaded. Remodeling is the process in which bone tissue is resorbed in areas of low stress distributions, and generated in areas of high stress distributions. Previous studies have utilized numerical methods and finite element methods to predict bone structure …

Fracture Of Bone Using Microindentation, Séverine Vennin

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Osteoporosis is a current disease which is especially of concern to post-menopausal women. It is characterized by a decrease of bone density and an increase in the risk of fracture. Interest in the fracture mechanisms with respect to the underlying biological structure of the bone is of great interest to researchers in this field. In this thesis, a new method based on microindentation on rat femurs was developed to determine the relation between the viscoelastic and the fracture properties of bone. The main goal is to measure the viscoelastic properties by using a dynamic mechanical analysis indentation method and then …

Computer-Based Skeletal Age Assessment Using Hand/Wrist Radiographs In Children 8-18 Years Old, Zhihong Ni

Browse all Theses and Dissertations

Children's skeletons mature at different rates, and they can be affected by a variety of factors including disease, hormone imbalance or genetics. The assessment of skeletal maturity is a frequently performed procedure that allows the detection of hormonal, growth or genetic disorders. Several methods have been developed to estimate skeletal maturity. Most methods evaluate hand/wrist radiographs using indicators such as the ratios of various bone widths, the onset of the ossification of epiphysis and epiphyseal-diaphyseal fusion. Among those methods, the FELS method differs from others in the application of different grades to each indicator and the provision of a confidence …

The Development Of A Mesenchymal Stem Cell Based Biphasic Osteochondral Tissue Engineered Construct, Scott Maxson

All Dissertations

The ability of human articular cartilage to respond to injury is poor. Once cartilage damage has occurred, an irreversible degenerative process can occur and will often lead to osteoarthritis (OA). An estimated 26.9 million of U.S. adults are affected by OA. Osteochondral grafting is currently used to treat OA and osteochondral defects; however, complications can develop at the donor site and defect area. Osteochondral tissue engineering provides a potential treatment option and alternative to osteochondral grafting. The long term goal of this work is to develop a tissue engineered mesenchymal stem cell (MSC) based osteochondral construct to repair cartilage damage. …

A Computational Model Of Apoptotic Osteocyte Correlation To Cortical Bone Remodeling Parameters, Michael Stephen Alexander

Master's Theses

The onset of osteoporosis caused by aging, disease states, and post-menopausal conditions significantly impacts patient quality of life, required healthcare funding, personal autonomy losses from increased fracture risk and the subsequent corrective surgery. Research has indicated that osteocyte apoptosis may be a key parameter in bone remodeling, raising the possibility of remodeling rate modulation for the mitigation of bone mass resorption. By developing therapies that target osteocyte apoptosis, it may be possible to prevent undesired bone remodeling activity while maintaining a healthy balance between damage formation in the form of microcracks induced by the strain environment and the removal of …

The Development Of An In Vivo Spinal Fusion Monitor Using Microelectromechanical (Mems) Technology To Create Implantable Microsensors, Lisa Anne Ferrara

ETD Archive

Surgical fusion of the spine is a conventional approach, and often last alternative, to the correction of a degenerative painful spinal segment. The procedure involves the surgical removal of the intervertebral disc at the problematic site, and the placement of a bone graft that is commonly harvested from the patients iliac crest and placed within the discectomized space. The surrounding bone is expected to incorporate and remodel into the bone graft to eventually provide an immobilized site. Spinal instrumentation often accompanies the bone graft to provide further immobility to the targeted site, thus augmenting the fusion process. However, the status …

Biomechanical Evaluation Of Locked And Non-Locked Constructs Under Axial And Torsion Loading, Vinit A. Patel

Browse all Theses and Dissertations

Locking compression plates are proven to be safe for use in open reduction and internal fixation (ORIF). The ORIF is a procedure performed to treat fractures. It has various combination of holes, the system provides more options for clinicians to use either locking screw or non-locking screws. This thesis investigates and determines the best construct with special locking and non-locking screws under both axial and torsion loading. Twenty femur constructs were assembled with 2 cm osteotomy gap between femur shaft and condyle, bridged with 4.5 mm - 10 holes condyle plates. Femurs were divided in to 4 groups according to …

Cutting Rate Effect On Temperature During Cortical Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack

Conference Papers

When bone is cut the occurrence of thermal damage to the bone is of major concern to the surgeon. If the temperature exceeds 44°C for longer than 1 min, bone repair is impaired (Eriksson et al, 1984) and necrosis may occur. Repeated use of cutting blades may reduce the cutting efficiency (Wevers et al, 1987; Toksvig-Larsen et al, 1992). Wevers et al also found that there is a greater force required to cut cortical bone using a blunt saw compared to new one.

Indentation Fracture Of Bovine Cortical Bone: Acoustic Emission Technique, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

Indentation cutting may result in microcracking and main crack growth which was previously reported. In this study, we recorded the AE signals produced by cracking processes during cutting on cortical bone, measuring the cutting force and correlating between load-displacement curves and AE activities.

An Unsupervised Fluoroscopic Analysis Of Knee Joint Kinematics, Charles Scott, Elisa H. Barney Smith

Electrical and Computer Engineering Faculty Publications and Presentations

Knowledge of the three dimensional positions of bones at a joint as a function of time is required to accurately model joint kinematics. 3-D bone geometry data from a static computer tomography (CT) images can be combined with time sequence information from 2-D video fluoroscopy images to produce 3-D position data over time. The process involves creating virtual X-rays from the CT image through digitally reconstructed radiograph (DRR) projections. Historically, the process of matching the 3-D and 2-D data has required human interaction. We have eliminated the need for manual initialization using a Monte Carlo technique with a variable search …

Methodology For Quantifying Biomechanical Bone Movement Of Transtibial Amputations, Johanna C. Bell

Browse all Theses and Dissertations

A controversy has long existed about an alternate below knee amputation procedure that may be more beneficial than the traditional transtibial amputation. The proponents of this alternate procedure that stabilizes the distal tibia and fibula claim it reduces excessive movement of the fibula relative to the tibia that occurs with common movements, such as walking. The purpose of this study is to develop a methodology for quantifying excessive movement of the fibula bone relative to the tibia bone in traditional below the knee amputations. The methodology will measure the movement and rotation of the fibula relative to the tibia. These …

Analysis Of Indentation Loading Of Cortical Bone Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

In this study, we recorded the number of Acoustic emission (AE) hits and related AE energy during indentation fracture of cortical bone using a PAC PCI-2 card and pico sensor. A threshold value of 43dB was used to filter premature trigger due to background noise. Registered AE hits had more than one count (threshold crossing). Amplifier gain was set at 40dB with a (0.1-1) MHz band pass filter. 8mm cubes of cortical bones were indented in the longitudinal direction at constant crosshead speed of 1 mm min-1 using a large 2D, 50˚ wedge indenter. We hypothesised that signals occurring as …