Biomedical Engineering and Bioengineering Commons^™

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 …

Poly(Ester Amide) And Poly(Ethyl Glyoxylate) Nanoparticles For Controlled Drug Release, Amira Mohamed Moustafa

Electronic Thesis and Dissertation Repository

The objective of this research was to develop polymeric nanoparticles (NPs) having improved drug release properties for drug delivery. Poly(ester amide)s (PEAs) are promising biodegradable polymers. PEA NPs were prepared via emulsification-evaporation and salting-out methods and optimized through by varying different processing parameters. Polymer-model drug conjugates based on PEAs containing L-aspartic acid and rhodamine B were synthesized and used for NP preparation. Release behavior was studied and compared to a control system with physically encapsulated rhodamine B. It was shown that the release of rhodamine B from the covalent system did not show the burst effect and exhibited a slower …

Development Of A Novel Device For The Perfusion Driven Decellularization Of Skeletal Muscle, Benjamin Kasukonis

Graduate Theses and Dissertations

Decellularization of skeletal muscle is a process that removes cellular components of skeletal muscle tissue while leaving behind the intact extracellular matrix (ECM). Skeletal muscle ECM is currently being studied as a biologic scaffold for repairing volumetric muscle loss (VML) because the removal of cells greatly reduces the antigenicity of the donor tissue. Decellularization usually relies on passive diffusion of detergents, surfactants and/or osmotic solutions to strip cells from the ECM. However, passive diffusion alone is usually not sufficient for complete removal of cells from the interior of large pieces of skeletal muscle using detergents, such as sodium dodecyl sulfate …

Laser-Assisted Surface Modification Of Hybrid Hydrogels To Prevent Bacterial Contamination And Protein Fouling, Guobang Huang

Electronic Thesis and Dissertation Repository

Silicone hydrogels have been extensively studied in the fields of contact lenses, tissue engineering, and drug delivery due to their good biocompatibility, high oxygen permeability, and proper light transmission. However, their applications in biomedical devices are limited by protein adsorption and bacterial contamination because of the hydrophobic surface of silicone, which will cause more irreversible protein adsorption. Several physical methods can be applied to create a hydrophilic surface on hydrogels, such as spin coating, physical vapor deposition, dip coating, drop casting, etc. Compared to the conventional methods, the matrix assisted pulsed laser evaporation (MAPLE) is suitable to produce biopolymer/polymer film …

A Rubric For Electrochemical Testing Of Metallic Biomaterials, Frederick G. De La Fuente

Master's Theses

Corrosion is a major factor for the failure of metallic medical implants. Testing a metal’s suseptability to corrosion prior to implantation is key to a successful implantation. Electrochemical processes were used in this study to evaluate the characteristics of corrosion of both AISI 316 stainless steel and titanium alloy Ti6Al4V, welded and non-welded. Linear, potentiodynamic, and cyclic polarization curves were produced by the PARC 2273 potentiostat showing the corrosion tendencies of the metals in four unique solutions 3.5% NaCl, 0.35% NaCl, phosphate buffered saline solution (PBS), and Butterfield phosphate buffered solution (BPS). The concentration of chloride ions in solutions affected …

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 …

Clear Circuit Contact Lens, Paul Hecker Ii, Phillip Azar, Alexander Do, Benny Ng, Errol Leon

Electrical Engineering

The clear active contact lens project aims to address safety and hazard awareness with an unexplored field of eye wear technology. With advancements in nanotechnology and the advent of circuits on contact lens, this project is one of the first research and development into this new field, following University of Washington and Google. The team focuses on the safety and biocompatibility of the contact lens for a comfortable ease of use. The designs push the limits of thin film printed technology with its pursuit of fine designs of 250μm antennas. The project streamlines the manufacturing process for a combination substrate …

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …

Characterizing The Reproducibility Of The Properties Of Electrospun Poly(D, L-Lactide-Co-Glycolide) Scaffolds For Tissue-Engineered Blood Vessel Mimics, Toni M. Pipes

Master's Theses

“Blood vessel mimics” (BVMs) are tissue-engineered constructs that serve as in vitro preclinical testing models for intravascular devices. The Cal Poly Tissue Engineering lab specifically uses BVMs to test the cellular response to stent implantation. PLGA scaffolds are electrospun in-house using the current “Standard Protocol” and used as the framework for these constructs. The performance of BVMs greatly depends on material and mechanical properties of the scaffolds. It is desirable to create BVMs with reproducible properties so that they can be consistent models that ultimately generate more reliable results for intravascular device testing. Reproducibility stems from the consistency of the …

Oriented Collagen And Applications Of Waveguide Evanescent Field Scattering (Wefs) Microscopy, Qamrun Nahar

Electronic Thesis and Dissertation Repository

In this thesis, Waveguide Evanescent Field Scattering (WEFS) microscopy is developed as a non-invasive, label-free live cell imaging technique. This new high-contrast imaging can be employed to study the first hundred nanometers from the surface as it utilizes the evanescent field of a waveguide as the illumination source. Previously, waveguide evanescent field fluorescence (WEFF) microscopy was developed as a fluorescence imaging technique comparable to the total internal reflection fluorescent (TIRF) microscopy. Both the WEFF and WEFS technique utilizes the same fundamental concepts except in WEFS microscopy imaging is accomplished without the application of any fluorescent labeling. In this work, bacterial …

Humidity Effect On The Structure Of Electrospun Core-Shell Pcl-Peg Fibers For Tissue Regeneration Applications, Adam P. Golin

Electronic Thesis and Dissertation Repository

With the aim of creating a biodegradable scaffold for tympanic membrane (TM) tissue regeneration, core-shell nanofibers composed of a poly(caprolactone) shell and a poly(ethylene glycol) core were created using a coaxial electrospinning technique. In order to create fibers with an optimal core-shell morphology, the effect of relative humidity (RH) on the core-shell nanofibers was systematically studied, with a FITC-BSA complex encapsulated in the core to act as a model protein. The core-shell nanofibers were electrospun at relative humidity values of 20, 25, 30, and 40% RH within a glove box outfitted for humidity control. The core-shell morphology of the fibers …

Drug Delivery To The Respiratory Tract Using Dry Powder Inhalers, Doaa M.R. Mossaad

Electronic Thesis and Dissertation Repository

Aerosols are an effective method to deliver therapeutic agents to the respiratory tract. Among aerosol generation systems, dry powder inhales have been attractive area of research for both local and systemic delivery of drugs. The challenge of any inhalation delivery system is to generate particles with an adequate range of particle sizes. In order to advance powder aerosol technologies, researchers have recognized the importance of investigating determinants affecting powder dispersion. The effect of particles’ surface characteristics, inhalation airflow rate, inhalation device, and development of an effective drug-carrier system are some of the fundamental areas that have been under investigation.

The …

Material Differences In Equine Cortical And Trabecular Bone, Ryan B. Allen

Master's Theses

A greater understanding of bone materials would be beneficial in creating more accurate computer models and in the making of biomedical products involving bone. This study set out to determine whether cortical and trabecular bone are two separate materials, or whether they are the same material with a variance in porosity. To answer this question, samples were taken from different sections of the equine metacarpus, underwent densitometry analysis and were statistically analyzed. The majority of results suggest that the material is the same between varying densities of bone and thus the same between cortical and trabecular bone. These particular results …

Surface Functionalization And Bioconjugation Of Nanoparticles For Biomedical Applications, Longyan Chen

Electronic Thesis and Dissertation Repository

Colloidal inorganic nanoparticles (NPs) have been attracting considerable interest in biomedicine, from drug and gene delivery to imaging, sensing and diagnostics. It is essential to modify the surface of nanoparticles to have enhanced biocompatibility and functionality for the in vitro and in vivo applications, especially in delivering locally and recognizing biomolecules. Herein, the goal of this research work is to develop advanced NPs with well-tailored surface functionalities and/or bio-functionality for the applications in cell tracking and analytes detection.

In the first project, quantum dots incorporating with gelatin nanoparticles (QDs-GNPs) have been developed for bioimaging applications. Two different approaches have been …

Microsphere Spray System For Wound Coverage, Nicholas J. Andersen

Theses and Dissertations--Biomedical Engineering

Spinal fusion is used to treat diseases or disorders of the spine by fusing together two or more vertebrae. Two associated risks with spinal fusion are infection and blood loss. Administration of tranexamic acid is used to prevent blood loss, and transfusions are given following blood loss. Surgical site infections are prevented with vancomycin powder spread into the surgical wound, while established infections are treated by debridement and delivery of antibiotics for 4 to 6 weeks. The present research explored an alternate method to prevent and treat blood loss or infection in spinal fusion. Poly(lactic-co-glycolic acid) (PLGA) microspheres was used …

Development Of A Moldable Composite Bone Graft Substitute Releasing Antibacterial And Osteogenic Drugs, Matthew E. Brown

Theses and Dissertations--Biomedical Engineering

Large infected bone defects (IBD) are very complicated to treat due to their high variability; they often require multiple procedures. Bone autografts are the gold standard for treatment but have several drawbacks, such as a need for a second surgery site, limited grafting material, and donor site morbidity. The objective of this research was to develop a moldable synthetic bone grafting material capable of releasing both antimicrobial and osteogenic drugs over a clinically relevant time course for the treatment of IBDs. Current treatment methods for large IBDs require two separate procedures to treat the bone defect and the infection.

This …

Mucoadhesive Films For Treatment Of Local Oral Disorders: Development, Characterization And In Vivo Testing, Sandeep K. Ramineni

Theses and Dissertations--Biomedical Engineering

Mucoadhesive drug delivery systems which are being used from 1980’s to avoid first pass metabolism of drugs, commercially exist for only systemic drug delivery with fast erosion times (15-60 min), that may not be appropriate for local oral disorders. The goal of this research was to develop and characterize mucoadhesive films with flexibility of carrying different drugs and proteins and provide sustained release for local treatment of oral disorders.

Mucoadhesive films composed of polyvinylpyrrolidone (PVP) and carboxymethlycellulose (CMC) were formulated with imiquimod, an immune response modifier. Problems such as solubilization of imiquimod to increase drug loading, uniformity in films and …

Bioerodible Calcium Sulfate Bone Grafting Substitutes With Tailored Drug Delivery Capabilities, Bryan R. Orellana

Theses and Dissertations--Biomedical Engineering

Bone regeneration or augmentation is often required prior to or concomitant with implant placement. With the limitations of many existing technologies, a biologically compatible synthetic bone grafting substitute that is osteogenic, bioerodible, and provides spacing-making functionality while acting as a drug delivery vehicle for bioactive molecules could provide an alternative to ‘gold standard’ techniques.

In the first part of this work, calcium sulfate (CS) space-making synthetic bone grafts with uniformly embedded poly(β-amino ester) (PBAE) biodegradable hydrogel particles was developed to allow controlled release of bioactive agents. The embedded gel particles’ influence on the physical and chemical characteristics of CS was …

Additives To Control Mechanical Properties And Drug Delivery Of Injectable Polymeric Scaffolds, Paul Fisher

Theses and Dissertations--Biomedical Engineering

In situ forming implants (ISIs) are popular due to their ease of use and local drug delivery potential, but they suffer from high initial drug burst, and release behavior is tied closely to solvent exchange and polymer properties. Additionally, such systems are traditionally viewed purely as drug delivery devices rather than potential scaffold materials due to their poor mechanical properties and minimal porosity. The aim of this research was to develop an injectable ISI with drug release, mechanical, and microstructural properties controlled by micro- and nanoparticle additives.

First, an injectable ISI was developed with appropriate drug release kinetics for orthopedic …

Tissue Engineering Scaffold Fabrication And Processing Techniques To Improve Cellular Infiltration, Casey Grey

Theses and Dissertations

Electrospinning is a technique used to generate scaffolds composed of nano- to micron-sized fibers for use in tissue engineering. This technology possesses several key weaknesses that prevent it from adoption into the clinical treatment regime. One major weakness is the lack of porosity exhibited in most electrospun scaffolds, preventing cellular infiltration and thus hosts tissue integration. Another weakness seen in the field is the inability to physically cut electrospun scaffolds in the frontal plane for subsequent microscopic analysis (current electrospun scaffold analysis is limited to sectioning in the cross-sectional plane). Given this it becomes extremely difficult to associate spatial scaffold …

Evaluation Of Tissue-Engineered Tendon Enthesis Polymer Constructs, Joshua A. Bundy Bs, Mary Beth Wade Phd, Hitomi Nakao Md, Phillip Mcclellan Phd, Qing Yu Phd, Robin Jacquet-Childs Ms, William J. Landis Phd

Williams Honors College, Honors Research Projects

Both scientists and clinicians have proposed tissue engineering as the future of medicine. The possibilities for tissue engineering, that is, fabrication of tissues and organs in the laboratory and their translation to patients, appear to be endless, and many believe that this new approach in medicine will result in abolishing many common ailments, injuries, and congenital defects. Injuries to a tendon enthesis, the normal tissue connection between tendon and bone, are of particular concern to clinicians because of their frequency and failure to repair as a result of surgery. While these injuries may not be life threatening, they can certainly …