Engineering Commons^™

Amine Functionalization Of Bacterial Cellulose For Targeted Delivery Applications, Justin Cook

Electronic Thesis and Dissertation Repository

Bacterial cellulose (BC), produced by acetic acid bacteria Gluconacetobacter xylinus, is ideal for delivery and related biomedical functions. It is FDA approved for wound dressings and internal applications, non-toxic to endothelial cells and has little effect on blood profiles. Conjugation of therapeutics to BC can be accomplished through the available alcohol groups of the anhydroglucose units (AGU), making targeted delivery possible. Amine was introduced to BC through a reaction involving epichlorohydrin and ammonium hydroxide. The chemical structure was analyzed using infrared spectroscopy and quantified through pH titration. Conjugation of amine to BC was demonstrated through fluorescein-5’-isothiocyanate (FITC) and bromocresol …

Butyl Rubber-Aliphatic Polyester Graft Copolymers For Biomedical Applications: Synthesis And Analysis Of Chemical, Physical And Biological Properties, Bethany A. Turowec

Electronic Thesis and Dissertation Repository

Biomaterials can be used in a wide variety of medical applications owing to their breadth of characteristics that can be imparted by varying their chemical structures. Butyl rubber (IIR), which is a copolymer of isobutylene (IB) and small percentages of isoprene (IP), is particularly attractive as a biomaterial because of its elastomeric mechanical properties, biocompatibility, impermeability and high damping characteristics. IIR is typically vulcanized through chemical-based crosslinking mechanisms. However, these methods are not acceptable for biological applications. This thesis focuses on the synthesis of IIR-polyester graft copolymers by grafting biodegradable and biocompatible polyesters including poly(caprolactone) (PCL) and poly(d,l-lactide) (PDLLA) to …

Sol-Gel Derived Biodegradable And Bioactive Organic-Inorganic Hybrid Biomaterials For Bone Tissue Engineering, Bedilu A. Allo

Electronic Thesis and Dissertation Repository

Treatments of bone injuries and defects have been largely centered on replacing the lost bone with tissues of allogeneic or xenogeneic sources as well as synthetic bone substitutes, which in all lead to limited degree of structural and functional recovery. As a result, tissue engineering has emerged as a viable technology to regenerate the structures and therefore recover the functions of bone tissue rather than replacement alone. Hence, the current strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function.

In this …

Engineering Nanocomposites For Antimicrobial Application, Binyu Yu

Electronic Thesis and Dissertation Repository

In this thesis, active and passive antimicrobial methods have been applied to fabricate antifouling surfaces. In the first study, we reported the synthesis and characterization of neat TiO₂ and Ag-TiO₂ composite nanofilms prepared on silicon wafer by sol-gel method. The synthesized Ag-TiO₂ thin films showed enhanced bactericidal activities compared to the neat TiO₂ nanofilm both in the dark and under UV illumination. The advantage of Ag-TiO₂ nano-composites is to expand the nanomaterial’s antibacterial function to a broader range of working conditions. In the second study, we reported the synthesis, characterization and environmental application of nitrogen …

Nanomechanics Of Electrospun Nanofibres For Tissue Engineering Of The Tympanic Membrane, Sara Makaremi

Electronic Thesis and Dissertation Repository

The Tympanic Membrane (TM), also known as the eardrum, includes layers of organized collagen nanofibres which play an essential role in sound transmission. Perforations that are caused by infection or accident must be repaired in order to restore hearing. Tympanoplasty is performed using grafts that are prepared from bladder, cartilage, temporal fascia and cadaveric skin. However, since mechanical properties of these grafts do not match those of the original TM, normal hearing is not fully restored. The goal of this study is to develop nanofibrous scaffolds for tissue engineering of the TM in order to circumvent the complications addressed with …

Calcium Phosphate-Based Resorbable Biomaterials For Bone Regeneration, Daniel O. Costa

Electronic Thesis and Dissertation Repository

Bone defects are a prevalent problem in orthopedics and dentistry. Calcium phosphate-based coatings and nanocomposites offer unique solutions towards producing scaffolds with suitable physical, mechanical and biological properties for bone regeneration.

We developed a novel method to synthesize hydroxyapatite (HA) particles with high aspect ratio using sol-gel chemistry and hydrothermal treatment. We obtained tunable pure-phase carbonated-HA in the form of micro/nanorods and nanowires (diameters 25-800 nm). To mimic the structure of bone, HA nanowires were homogenously mixed within poly(ε-caprolactone) (PCL) to produce nanocomposites with improved mechanical properties as determined by uniaxial tensile testing.

Surface chemistry and topography of biomaterials play …

Poly(Vinyl Alcohol) Nanocomposite Hydrogels For Intervertebral Disc Prostheses, Elaine Wong

Electronic Thesis and Dissertation Repository

Spinal fusion is currently the gold standard for surgical intervention of intervertebral disc (IVD) diseases leading to neck and back pain failing conservative treatments. However, fusion removes motion between the vertebrae and can result in adjacent level degeneration. Total disc replacement (TDR) is an emerging treatment alternative that preserves motion, but materials found in clinically available devices bear little resemblance to the properties of the native IVD. Poly(vinyl alcohol) (PVA) hydrogels are biocompatible, have mechanical behaviour similar to natural tissues, and properties that can be tuned by varying polymer concentration and physical crosslinking through freeze-thaw cycling. Furthermore, their properties can …

Encapsulation And Controlled Release Of Rhu-Erythropoietin From Chitosan Biopolymer Nanoparticles, Cody Bulmer

Electronic Thesis and Dissertation Repository

The objective of this research project was to develop a drug delivery system for recombinant human erythropoietin (rHu-EPO), a glycoprotein hormone used in the treatment of renal anaemia and chemotherapy induced anaemia, using the biopolymer chitosan as the base component. Two types of chitosan nanoparticles were produced through ionotropic gelation using flush mixing with either tripolyphosphate (TPP) or carrageenan polymer. Chitosan-TPP and chitosan-carrageenan nanoparticles were generated under a variety of conditions to evaluate the effects of chitosan concentration, chitosan to anion mass ratio and solution pH on the nanoparticle characteristics of particle diameter, surface charge and particle size distribution. A …

Bacterial Cellulose Templates For Nano-Hydroxyapatite Fibre Synthesis, Jordan A. Demello

Electronic Thesis and Dissertation Repository

Guided bone regeneration is a medical procedure which induces in vivo re-growth of bone using membranes and osteopromoting fillers. In this work, bacterial cellulose fibers were isolated and used as a basis for biomimetic hydroxyapatite growth, with the ultimate goal of producing GBR filler materials. Acetobacter xylinum generated BC using various carbon sources. Fibers were treated with phosphoric acid to phosphorylate functional groups and preconditioned with calcium to nucleate the HA. Simulated body fluid (SBF) furthered the growth. Over 14 days, the product was characterized via EDX, SEM, FTIR, and XRD. The effect of media composition, phosphorylation time, pretreatment, and …

Controlled Delivery Of Serp-1 Protein From Poly(Vinyl Alcohol) Hydrogel, Karen L. Kennedy

Electronic Thesis and Dissertation Repository

Poly(vinyl alcohol) (PVA) was selected and evaluated as a controlled drug delivery matrix for Serp-1, a potential new therapeutic with anti-inflammatory properties for control of restenosis. PVA hydrogels, containing a high water content, can be formed by physical crosslinking via a process involving freezing and thawing the material in multiple cycles. PVA, being a well known biomaterial, is suited for biomedical applications and the high water content and hydrophilicity provides a friendly environment for the delivery of large protein based drugs. Using bovine serum albumin (BSA) as a model protein, the controlled release properties of PVA were investigated. Release profiles …