Biomaterials Commons^™

Materials Design With Polylactic Acid-Polyethylene Glycol Blends Using 3d Printing And For Medical Applications., Jeremiah R. Bauer

Electronic Theses and Dissertations

This thesis is an examination of two material systems derived from polylactic acid (PLA) and polyethylene glycol (PEG). PLA is a polymer commonly sourced from renewable sources such as starches and sugars. It is a relatively strong, biodegradable polymer, making it ideal for use in the body. Even though it has a relative high strength, PLA is also brittle leading to the use of plasticizers to increase flexibility. One such plasticizer is PEG, which is a material that can exist at room temperature as either a thin liquid, or a hard waxy solid depending on the molecular weight. The first …

Osteon Mimetic Scaffolding, Janay Clytus

Senior Theses

The purpose of this research is to provide an alternative to naturally derived bone grafts. There is a gap in the supply of donors and the demand of bone tissue. Artificial scaffold creation can work as an implant and decrease the shortage of bone grafts and increase the range of injuries that can be repaired. Current research focuses on optimizing mechanical properties such as porosity, improving vascularization using cells, and generating osteoconductivity. For osteodifferentiation, mesenchymal stem cells (MSCs) can differentiate into mesodermal lineages such as chondrocytes, osteoblasts, adipocytes, and tenocytes by supplementing cultures with lineage-specific soluble factors (Marchetti). Co-culturing ECFCs …

Collective Adhesion And Displacement Of Retinal Progenitor Cells Upon Extracellular Matrix Substrates Of Transplantable Biomaterials, Ankush Thakur, Shawn Mishra, Juan Pena, Jing Zhou, Stephen Redenti, Robert Majeska, Maribel Vazquez

Publications and Research

Strategies to replace retinal photoreceptors lost to damage or disease rely upon the migration of replacement cells transplanted into sub-retinal spaces. A significant obstacle to the advancement of cell transplantation for retinal repair is the limited migration of transplanted cells into host retina. In this work, we examine the adhesion and displacement responses of retinal progenitor cells on extracellular matrix substrates found in retina as well as widely used in the design and preparation of transplantable scaffolds. The data illustrate that retinal progenitor cells exhibit unique adhesive and displacement dynamics in response to poly-l-lysine, fibronectin, laminin, hyaluronic acid, and Matrigel. …

Synthesis And Characterization Of Blue Light Poly(Β-Amino Ester)S, Nicholas John Kohrs

Theses and Dissertations--Biomedical Engineering

Volumetric muscle loss (VML) is a debilitating injury which results in full or partial loss of function. Current clinical options utilize tissue grafts and bracing to restore function. Tissue graft implantation oftentimes leads to serious complications, some of which end in graft rejection and thereby necessitate further surgeries and procedures. Polymeric scaffolds show promise as scaffolding systems due to their mechanical properties and overall degradation profiles. Scaffolds need appropriate mechanical properties, 10-60 kPa modulus, and overall degradation times, five days to two weeks, to initiate tissue regeneration. Poly(β-amino ester)s (PBAE), a class of synthetic polymers, act as a safe biocompatible …

Decellularized Matrices Effect On The Adaptive Immune Response, Kegan Sowers

Theses and Dissertations

Decellularized extracellular matrices have been a growing area of interest in the biomedical engineering fields of tissue engineering and regenerative medicine.As these materials move toward clinical applications, the immune response to these materials will be a driving force toward their success in clinical approaches. Fully digested decellularized matrix constructs derived from porcine liver, muscle and lung were created to test the adaptive immune response. Hydrogel characterization ensured that the materials had relatively similar stiffness levels to reduce variability, and in vitro studies were conducted. Each individual construct as well as a gelatin control were plated with a co-culture of macrophages …

Developing Vascular Graft From Adipose-Derived Stem Cells, Ashley C. Apil

Research Opportunities for Engineering Undergraduates (ROEU) Program 2017-18

This project aims to differentiate adipose-derived stem cells into fibroblasts through the addition of platelet-derived growth factor (PDGF) into the culture media. Differentiation protocol will be optimized, then successful differentiation will be verified through PCR analysis. The ASC-fibroblasts will then be seeded into a ring construct as outlined by the protocol by Lam et al. The ring constructs will be tensile tested and analyzed through histology to characterize their strength and cellularity.

Electrochemical And Spectroscopic Study Of Peptide-Template Melanins, Daniel Courter, Olivia Rossi, Zhen Tian

Honors Theses and Capstones

Melanins are organic polymers made up of 5,6-dihydroxyindole carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI). Biochemical systems synthesize melanins through a complex reaction pathway. Previous research exhibited that naturally-occurring melanins (NatMel) and their synthetic analogues (SynMel) can potentially serve as electrode materials for aqueous charge storage devices. Small surface area creates technical challenges for these melanins as charge storage materials. This research herein demonstrates that the structure of melanins can affect the charge storage capacities of monovalent Na⁺cations and divalent Mg²⁺ cations. 2-D sheet-like peptide melanins (PepMel) were synthesized into tripeptides consisting of aspartic acid (D), phenylalanine (F), …

Developing A 3d In Vitro Model By Microfluidics, Hung-Ta Chien

Dissertations and Theses

In vitro tissue models play an important role in providing a platform that mimics the realistic tissue microenvironment for stimulating and characterizing the cellular behavior. In particular, the hydrogel-based 3D in vitro models allow the cells to grow and interact with their surroundings in all directions, thus better mimicking in vivo than their 2D counterparts. The objective of this thesis is to establish a 3D in vitro model that mimics the anatomical and functional complexity of the realistic cancer microenvironment for conveniently studying the transport coupling in porous tissue structures. We pack uniform-sized PEGDA-GelMA microgels in a microfluidic chip to …

Studying Mass And Mechanical Property Changes During The Degradation Of A Bioadhesive With Mass Tracking, Rheology And Magnetoelastic (Me) Sensors, Zhongtian Zhang

Dissertations, Master's Theses and Master's Reports

In this research, the degradable polymer 4-arm poly (ethylene glycol)-glutaric acid-dopamine (PEG-GA-DM₄) was synthesized. The degradation behavior of crosslinked PEG-GA-DM₄ bioadhesive was studied with mass tracking, oscillatory rheology, and magnetoelastic (ME) sensors. Changes in mechanical properties were correlated with both dry mass and wet mass changes during the degradation. The results indicate that the loss of mechanical property in the bioadhesive can take place without losing the dry mass. The mass loss profile cannot describe the degradation behavior completely. In addition to studying the degradation of PEG-GA-DM₄, this research also confirms the application of ME …

Comparison Of Artificial Saliva Vs Saline Solution On Rate Of Suture Degradation In Oropharyngeal Surgery, Jenna W. Briddell, Luke Riexinger, Jove Graham, Donna M. Ebenstein

Faculty Journal Articles

IMPORTANCE Absorbable sutures are designed to degrade and lose strength over time. Manufacturers warn that exposure to various body fluids can change the estimated degradation rate of these sutures, but few studies have been conducted to quantify the degree of change associated with saliva.

OBJECTIVE To quantify the association of increased loss of strength of sutures over time after exposure to artificial saliva (hereinafter referred to as “saliva”).

DESIGN, SETTING, AND PARTICIPANTS This experimental in vitro study was conducted at Bucknell University (Lewisburg, Pennsylvania) from June 19, 2015, to July 4, 2015. No participants were involved. The loss of strength …

Integration Of Biology, Ecology And Engineering For Sustainable Algal‑Based Biofuel And Bioproduct Biorefinery, James Allen, Serpil Unlu, Yaşar Demirel, Paul N. Black, Wayne R. Riekhof

Department of Chemical and Biomolecular Engineering: Faculty Publications

Despite years of concerted research efforts, an industrial-scale technology has yet to emerge for production and conversion of algal biomass into biofuels and bioproducts. The objective of this review is to explore the ways of possible integration of biology, ecology and engineering for sustainable large algal cultivation and biofuel production systems. Beside the costs of nutrients, such as nitrogen and phosphorous, and fresh water, upstream technologies which are not ready for commercialization both impede economic feasibility and conflict with the ecological benefits in the sector. Focusing mainly on the engineering side of chemical conversion of algae to biodiesel has also …

An Injectable Thermosensitive Biodegradable Hydrogel Embedded With Snap Containing Plla Microparticles For Sustained Nitric Oxide (No) Delivery For Wound Healing, Nikhil Mittal

Dissertations, Master's Theses and Master's Reports

After injury, wound healing is a complex sequential cascade of events essential for the proper recovery of the wound without the scar formation. Nitric oxide (NO) is a small, endogenous free-radical gas with antimicrobial, vasodilating and growth factor stimulating properties. NO has wide biomedical application especially in wound healing however, its usability is hindered due its administration problem as it is highly unstable.

In this work, poly (l-lactic acid) microparticles encapsulated with NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) were prepared using water-in-oil-water double emulsion solvent evaporation method for controlled delivery for NO at the specific site. The NO release from SNAP-PLLA microparticles …

Reversibly Switching Adhesion Of Smart Adhesives Inspired By Mussel Adhesive Chemistry, Ameya R. Narkar

Dissertations, Master's Theses and Master's Reports

Catecholic groups in mussel adhesive proteins transition from being strongly adhesive in a reduced state under acidic conditions to being weakly adhesive in an oxidized state under basic conditions. Here, we exploit this pH responsive behavior of catechol and demonstrate that its oxidation state can be manipulated by incorporation of boronic acid to facilitate reversible transitions between strong and weak adhesion. Our first approach involved the addition of 3- acrylamido phenylboronic acid (APBA) to dopamine methacrylamide (DMA) containing adhesives. The synthesized adhesives showed strong adhesion to quartz surface in an acidic medium (pH 3), while weak adhesion was observed on …

Degradability Of Poly(Ethylene) Based Microgels And Methods Of Improving High Polydispersity Index, Abrar Alniemi

Williams Honors College, Honors Research Projects

In order to improve upon the utilization of poly(ethylene glycol) (PEG) microgel-based scaffolds in drug delivery applications, this work explores the use of degradable and non-degradable PEG for tunable scaffolds. Previously, issues concerning the required uniformity in microgel size and low polydispersity index have been encountered. As such, methods of refining polymer synthesis, microgel fabrication, and microgel size separation were explored. Overall, no solution has been found to correct the issue for the microgels were still observed to have high polydispersity index regardless of varied troubleshooting alterations.

Effects Of Protein-Coated Nanofibers On Conformation Of Gingival Fibroblast Spheroids: Potential Utility For Connective Tissue Regeneration, Gili Kaufman, Ryan A. Whitescarver, Laiz Nunes, Xavier-Lewis Palmer, Drago Skrtic, Wojtek Tutak

Engineering Technology Faculty Publications

Deep wounds in the gingiva caused bytrauma or surgery require a rapid and robust healing of connective tissues. Wepropose utilizing gas-brushed nanofibers coated with collagen and fibrin for that purpose. Our hypotheses are that protein-coated nanofibers will: (i) attract and mobilize cells in various spatial orientations, and (ii) regulate the expression levels ofspecific extracellular matrix (ECM)-associated proteins, determining the initial conformational nature ofdense and soft connective tissues. Gingival fibroblast monolayers and3D spheroids were cultured onECMsubstrate and covered with gas-blown poly-(DL-lactide-co-glycolide)(PLGA) nanofibers (uncoated/coated with collagen and fibrin). Cell attraction and rearrangement was followed byF-actin staining and confocal microscopy. Thicknesses ofthe cell …

Development Of Entubulation Strategies For Treating Central Nervous System Injuries, Ivy Brosch

Williams Honors College, Honors Research Projects

According to the McKnight Brain Institute, at least 10,000 people annually in the USA suffer from a central nervous system (CNS) injury. These injuries can cause serve disabilities including paralysis. Due to the complexity of the spinal cord, it is common that potential CNS treatments are first applied to an optic nerve crush (ONC) model in rats. Two proposed treatments were employed; one where nerve growth factor (NGF) was immobilized to a chitosan substrate to stimulate axonal regeneration, and the other using pentadecafluorooctanoyl chloride modified methacrylamide chitosan (MAC(Ali15)F) hydrogel to enhance local oxygenation. The two different treatments were formed into …

Wearable Hearing Accessory Technology, Tyler Cindea, Jaime Alcorn, Brooke Draper, Kyle Glascott, Ben Hanna, Robert Thoerner

Williams Honors College, Honors Research Projects

We set out in August 2017 to develop an active noise suppressing device that would be usable both in military and civilian activities. Due to constraints in knowledge and time, we decided our best course of action was to divide the project into two equal projects with the hope to be able to combine them into a single project at the end of the allotted time. This consisted of an active noise suppression device and a passive noise suppression device. The passive device would have no electronic components and the active device would be pure circuitry with no housing. This …

Molded Features In Pdms For Fabricating Bacterial Cellulose For Various Geometries, Mitchell Habegger

Williams Honors College, Honors Research Projects

The purpose of producing features on bacterial cellulose (BC) is to facilitate the elongation and alignment for cells, in this case Normal Human Dermal Fibroblast (NHDF) cells. The elongated cells have applications in wound healing, tissue engineering, disease diagnostics, and many other fields. Experiments were run to test the effectiveness of transferring features to BC sheets from features induced by fracturing on polydimethylsiloxane (PDMS) and those duplicated from molds with existing features. The features were duplicated to BC sheets by either air drying or Guided Assembly-Based Biolithography (GAB). The research results showed that fracture inducing on PDMS produced very small …

Engineering Surface Properties To Modulate Inflammation And Stem Cell Recruitment Through Macrophage Activation, Kelly M. Hotchkiss

Theses and Dissertations

Biomaterials are becoming the most commonly used therapeutic method for treatment of lost or damaged tissue in the body. Metallic materials are chosen for high strength orthopaedic and dental applications. Titanium (Ti) implants are highly successful in young, healthy patients with the ability to fully integrate to surrounding tissue. However the main population requiring these corrective treatments will not be healthy or young, therefore further research into material modifications have been started to improve outcomes in compromised patients. The body’s immune system will generate a response to any implanted material, and control the final outcome. Among the first and most …

The Effects Of Emerging Technology On Healthcare And The Difficulties Of Integration, Skyler J. Pavlish-Carpenter

Honors Undergraduate Theses

Background: Disruptive technology describes technology that is significantly more advanced than previous iterations, such as: 3D printing, genetic manipulation, stem cell research, innovative surgical procedures, and computer-based charting software. These technologies often require extensive overhauls to implement into older systems and must overcome many difficult financial and societal complications before they can be widely used. In a field like healthcare that makes frequent advancements, these difficulties can mean that the technology will not be utilized to its full potential or implemented at all.

Objective: To determine the inhibiting factors that prevent disruptive technology from being implemented in conventional healthcare.

Methods: …