Biomaterials 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 …

Low Molecular Weight Glucosamine/L-Lactide Copolymers As Potential Carriers For The Development Of A Sustained Rifampicin Release System: Mycobacterium Smegmatis As A Tuberculosis Model, Jorge Ragusa

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Tuberculosis, a highly contagious disease, ranks as the second leading cause of death from an infectious disease, and remains a major global health problem. In 2013, 9 million new cases were diagnosed and 1.5 million people died worldwide from tuberculosis. This dissertation aims at developing a new, ultrafine particle-based efficient antibiotic delivery system for the treatment of tuberculosis. The carrier material to make the rifampicin (RIF)-loaded particles is a low molecular weight star-shaped polymer produced from glucosamine (molecular core building unit) and L-lactide (GluN-LLA). Stable particles with a very high 50% drug loading capacity were made via electrohydrodynamic atomization. Prolonged …

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 …

Effect Of Plasticizer On Oxygen Permeability Of Cast Polylactic Acid (Pla) Films Determined Using Dynamic Accumulation Method, Kurniawan Yuniarto, Bruce A. Welt, Aris Purwanto, Hadi Karia Purwadaria, Ayman Abdellatief, Titi C. Sunarti, Setyo Purwanto

Journal of Applied Packaging Research

Polylactic acid (PLA) is becoming an increasingly important biopolymer for packaging applications. PLA brittleness limits its applicability. This study evaluated PLA properties with increasing amounts of added polyethylene glycol (PEG) plasticizer. Oxygen transmission rate (OTR) of cast films was determined using the newly available Dynamic Accumulation (DA) method. Arrhenius temperature sensitivity of OTR and polymer Permeability was also determined. Permeability of neat PLA is 4.848 ml mm (STP)/m² s kPa; hence, 4.84 ml mm (STP)/m² s kPa, 4.07 ml mm (STP)/m² s kPa and 5.42 ml mm (STP)/m² s kPa by adding PEG 1 %, 5% …

A Collagen‐Glycosaminoglycan‐Fibrin Scaffold For Heart Valve Tissue Engineering Applications, Claire Brougham, Stefan Jockenhoevel, Thomas Flanagan, Fergal O'Brien

Conference Papers

The field of heart valve biology and tissue engineering a heart valve continue to expand. The presentatio ns at this meeting reflect the advances made in both areas due to the multi-disciplinary approach taken by many laboratories.

Improvements To Uhmwpe, Brooke Mckelvogue

Journal of Undergraduate Research at Minnesota State University, Mankato

Ultra high molecular weight polyethylene (UHMWPE) is a material used in artificial implants for articular joint replacements. However, these implants have a limited lifespan in which the patient will be pain-free due to the wear of the UHMWPE components. Recently crosslinking, or exposing the material to radiation, has been used to extend the wear resistance of UHMWPE. Crosslinking introduces another set of drawbacks; mainly the reduction of the fracture toughness of UHMWPE and the generation of free radicals, which leave the polymer vulnerable to damage from oxidation. Currently, research is being conducted on other methods to increase the wear resistance …

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 …

Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Due to the high prevalence of arthritis and cartilage-related injuries, tissue engineers are studying ways to grow cartilage tissue replacements. Resilin, an elastomeric protein found in insect cuticles, is known for its extraordinary resilience and elasticity. In previous studies, recombinant resilin-based hydrogels, or cross-linked protein networks, exhibited potential for use in cartilage tissue scaffolds. Our lab successfully developed resilin-based proteins with a sequence based on the mosquito gene and showed that resilin-based hydrogels possess mechanical properties of the same order of magnitude as native articular cartilage. In addition, these mechanical properties can be controlled by changing the protein concentration. To …

The Role Of Metal Oxide Layers In The Sensitivity Of Lactate Biosensors Subjected To Oxygen-Limited Conditions, Elizabeth Andreasen, Lia Stanciu, Aytekin Uzunoglu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Amperometric lactate biosensors are used to detect lactate concentration in blood and tissues, which is integral in identifying cyanide poisoning, septic shock, and athletic condition. The construction of lactate biosensors with high sensitivity, selectivity, and stability is imperative to diagnose and determine these medical conditions. Lactate detection is currently limited to oxygen-rich environments due to the fact that oxygen is a limiting factor in the lactate reaction. To circumvent this problem, researchers have developed mediators or alternate, oxygen-free enzymes to improve sensitivity. In our study, ceria (CeO₂) with high oxygen storage capacity (OSC) was introduced to the enzyme …

Biological Implications Of Satellite Cells For Scaffold-Based Muscle Regenerative Engineering, Maggie R. Del Ponte, Charter Chain, Meng Deng Dr., Feng Yue Dr., Shihuan Kuang Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Satellite cells are anatomically localized along the surface of muscle fibers and have been regarded as a population of muscle-specific progenitors that are responsible for muscle regeneration. In response to muscle injuries, satellite cells are activated to enter the cell cycle, then proliferate and differentiate into mature muscle cells to regenerate damaged myofibers. Unfortunately, this natural repair mechanism is interrupted in conditions such as muscle degenerative diseases or volumetric muscle loss. The function of stem cells is regulated by signals from their local microenvironment which is called the stem cell niche. Current satellite cell-based strategies such as direct cell transplantation …

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 …

Application Of Limited Mixing In The Hele-Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

Md Mahmudur Rahman

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

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 …

Perspectives For Titanium-Derived Fillers Usage On Denture Base Composite Construction, Nidal Elshereksi

Nidal Elshereksi

Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong.They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in …

Investigation Of Membrane Mechanics Using Spring Networks: Application To Red-Blood-Cell Modelling, Mingzhu Chen, Fergal Boyle

Articles

In recent years a number of red-blood-cell (RBC) models have been proposed using spring networks to represent the RBC membrane. Some results predicted by these models agree well with experimental measurements. How- ever, the suitability of these membrane models has been questioned. The RBC membrane, like a continuum mem- brane, is mechanically isotropic throughout its surface, but the mechanical properties of a spring network vary on the network surface and change with deformation. In this work spring-network mechanics are investigated in large deformation for the first time via an assessment of the effect of network parameters, i.e. network mesh, spring …

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 …

Modeling The Costs Of Cellulosic Biofuel, Maxwell Berube

Honors College

This thesis seeks to establish the private and external costs of the production of cellulosic biofuel from woody biomass. A model is presented which explores the economic feasibility of a firm producing this biofuel using a particular process. Specifically, it examines the input costs including the external costs of transportation, the external cost of pollutants produced by the firm, and potential cost reductions that may be applied as a result of learning from accumulated experience. In order to evaluate the feasibility of the plant, a spreadsheet model is built and a Monte Carlo simulation is run in order to evaluate …

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 …

Application Of Limited Mixing In The Hele-Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

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 …

Alumina Ceramic For Dental Applications: A Review Article., Ahmed A. Madfa

Ahmed A. Madfa

Alumina has received considerable attention and has been historically wellaccepted as biomaterials for dental and medical applications. This article reviews the applications of this material in dentistry. It presents a brief history, dental applications and methods for improving the mechanical properties of aluminabased materials. It also offers perspectives on recent research aimed at the further development of alumina for clinical uses, at their evaluation and selection, and very importantly, their clinical performance. This article also stated about the Functionally Graded Materials (FGMs) which has been conceived as a new material design approach to improve performance compared to traditional homogeneous and …

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 …

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

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 …