Biomedical Engineering and Bioengineering Commons^™

Piezoelectric And Conductive Polymer Based Flexible Devices Enabling Cardiovascular Health Sensing And Energy Harvesting, Andrew Closson

Dartmouth College Ph.D Dissertations

Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible …

Antimicrobial Mechanisms Of Biomaterials: From Macro To Nano, Shounak Roy, Sanchita Sarkhel, Deepali Bisht, Samerender Nagam Hanumantharao, Smitha Rao, Amit Jaiswal

Michigan Tech Publications

Overcoming the global concern of antibiotic resistance is one of the biggest challenge faced by scientists today and the key to tackle this issue of emerging infectious diseases is the development of next-generation antimicrobials. The rapid emergence of multi-drug resistant microbes, superbugs and mutated strains of viruses have fueled the search for new and alternate antimicrobial agents with broad-spectrum biocidal activity. Biomaterials, ranging from macroscopic polymers, proteins, and peptides to nanoscale materials such as nanoparticles, nanotubes and nanosheets have emerged as effective antimicrobials. An extensive body of research has established the antibacterial and antiviral efficiencies of different types of biomaterials. …

Mechanical Properties Of Nanoparticles In The Drug Delivery Kinetics, Kaivon Assani, Amy Neidhard-Doll, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Nanoparticle formulation is a recently developed drug delivery technology with enhanced targeting potential. Nanoparticles encapsulate the drug of choice and delivers it to the target via a targeting molecules (ex. antigen) located on the nanoparticle surface. Nanoparticles can even be targeted to deeply penetrating tissue and can be modeled to deliver drugs through the blood brain barrier. These advancements are providing better disease targeting such as to cancer and Alzheimer’s. Various polymers can be manufactured into nanoparticles. The polymers examined in this paper are polycaprolactone (PCL), poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and poly(glycolic acid) (PGA). The purpose of this …

Nanoparticulate Carriers For Drug Delivery, Samantha Lokelani Crossen, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Drug delivery with nanoparticulate carriers is a new and upcoming research area that is making major changes within the pharmaceutical industry. Nanoparticulate carriers are discussed, particularly, engineered nanoparticulate carriers used as drug delivery systems for targeted delivery. Nanoparticulate carriers that are used for drug delivery systems include polymers, micelles, dendrimers, liposomes, ceramics, metals, and various forms of biological materials. The properties of these nanoparticulate carriers are very advantageous for targeted drug delivery and result in efficient drug accumulation at the targeted area of interest, reduced drug toxicity, reduced systemic side effects, and more efficient use of the drug overall. Nanoparticlulate …

Investigation Of Human Adipose-Derived Stem-Cell Behavior Using A Cell-Instructive Polydopamine-Coated Gelatin-Alginate Hydrogel., Settimio Pacelli, Aparna R Chakravarti, Saman Modaresi, Siddharth Subham, Kyley Burkey, Cecilia Kurlbaum, Madeline Fang, Christopher A Neal, Adam J Mellott, Aishik Chakraborty, Arghya Paul

Chemical and Biochemical Engineering Publications

Hydrogels can be fabricated and designed to exert direct control over stem cells' adhesion and differentiation. In this study, we have investigated the use of polydopamine (pDA)-treatment as a binding platform for bioactive compounds to create a versatile gelatin-alginate (Gel-Alg) hydrogel for tissue engineering applications. Precisely, pDA was used to modify the surface properties of the hydrogel and better control the adhesion and osteogenic differentiation of human adipose-derived stem cells (hASCs). pDA enabled the adsorption of different types of bioactive molecules, including a model osteoinductive drug (dexamethasone) as well as a model pro-angiogenic peptide (QK). The pDA treatment efficiently retained …

Nanoparticles For Targeted Drug Delivery To Cancer Stem Cells: A Review Of Recent Advances, Yavuz Nuri Ertas, Keyvan Abedi Dorcheh, Ali Akbari, Esmaiel Jabbari

Faculty Publications

Cancer stem cells (CSCs) are a subpopulation of cells that can initiate, self-renew, and sustain tumor growth. CSCs are responsible for tumor metastasis, recurrence, and drug resistance in cancer therapy. CSCs reside within a niche maintained by multiple unique factors in the microenvironment. These factors include hypoxia, excessive levels of angiogenesis, a change of mitochondrial activity from aerobic aspiration to aerobic glycolysis, an upregulated expression of CSC biomarkers and stem cell signaling, and an elevated synthesis of the cytochromes P450 family of enzymes responsible for drug clearance. Antibodies and ligands targeting the unique factors that maintain the niche are utilized …

Surface-Eroding Drug Delivery Films For Sequential And/Or Intermittent Release Of Psychoactive Drugs, Jason Price

Honors Theses

ABSTRACT JASON BLAKE PRICE: Surface-Eroding Drug Delivery Films for Sequential and/or

Intermittent Release of Psychoactive Drugs For patients with psychiatric diseases, adherence to medication schedules, medication

errors, and abuse are common issues. Promising new forms of therapy for these patients, such as micro-dosed lysergic acid diethylamide (LSD), where patients receive 10-20% of a full dose every third day, present further drug delivery challenges. Sequential or intermittent release of drugs from an implanted device could ensure long-term drug compliance, automate drug dosing during the life of the implant, and eliminate potential for abuse and medication errors. To this end, we generated …

Hydrolytic Degradation Study Of Polyphosphazene-Plga Blends, Riley Blumenfield

Honors Scholar Theses

The synthesis and in vitro degradation analysis of thin films of poly[(glycineethylglycinato)₇₅(phenylphenoxy)₂₅phosphazene]
(PNGEG₇₅PhPh₂₅) and poly[(ethylphenylalanato)₂₅(glycine-
ethylglycinato)₇₅phosphazene] (PNEPA₂₅GEG₇₅) blended with poly(lactic-co-glycolic acid) (PLGA) was conducted to determine the blends’ potential for use as scaffolding materials for tissue regeneration applications. The samples were synthesized with glycylglycine ethyl ester (GEG) acting as the primary substituent side group, with cosubstitution by phenylphenol (PhPh) and phenylalanine ethyl ester (EPA) to make the final product [1]. Blends of 25% polyphosphazene, 75% PLGA and 50% polyphosphazene, 50% PLGA were …

Coatings On Mammalian Cells: Interfacing Cells With Their Environment, Kara A. Davis, Pei-Jung Wu, Calvin F. Cahall, Cong Li, Anuhya Gottipati, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

The research community is intent on harnessing increasingly complex biological building blocks. At present, cells represent a highly functional component for integration into higher order systems. In this review, we discuss the current application space for cellular coating technologies and emphasize the relationship between the target application and coating design. We also discuss how the cell and the coating interact in common analytical techniques, and where caution must be exercised in the interpretation of results. Finally, we look ahead at emerging application areas that are ideal for innovation in cellular coatings. In all, cellular coatings leverage the machinery unique to …

Synthesis, Optimization, And Degradation Of A Fish Glue/Plga Polymer., Adam T. Schworer 1989-

Electronic Theses and Dissertations

Biomaterials used for tissue engineering, specifically polymers, come from either naturally occurring, like gelatin or collagen, or synthetic sources, such as polyesters. Often times, it is advantageous to combine biomaterials in order to maximize certain material properties, such as cellular adhesion and degradation. The purpose of this study is to provide direction for the synthesis, characterization, and a combination of a combination biomaterial between fish glue (FG), a natural source polymer, and poly-lactic-co-glycolic acid (PLGA), a synthetically made polyester. First, FG is characterized for molecular weight via Gel Permeation Chromatography, GPC. Two combination methods to mix FG/PLGA solutions are then …

Solute Partitioning In Elastin-Like Polypeptides: A Foundation For Drug Delivery Applications, Eric Helm

ETD Archive

No abstract provided.

Production Of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin And Process Optimization, Homaira Siddiqui

Electronic Thesis and Dissertation Repository

Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted …

Synthesis And Characterization Of Biodegradable Poly(Vinyl Esters) With Hdac Inhibitory Activity, Kyle Lawrence Horton

Wayne State University Theses

HDAC inhibitors are known to have anti-inflammatory properties. HDAC inhibitors are used in combination with Oct4 to generate induced pluripotent stem cells. I hypothesized that polyesters based on simple aliphatic HDAC inhibitors like valproic acid (VPA) and phenylbutyric acid (PBA) can serve as alternatives to existing polyester biomaterials with improved anti-inflammatory properties and as scaffolds for generation of iPSCs when used in combination with layer-by-layer thin films delivering reprogramming transcription factors. Vinyl ester of phenylbutyric acid (VEPA) and vinyl ester of valproic acid (VEVA) were synthesized from their carboxylic acid precursors using an iridium complex catalyst at yields as high …

Synthesis And Characterization Of Ph-Responsive Elastin-Like Polypeptides With Different Configurations, Mingjie Tang

ETD Archive

Elastin-like polypeptides (ELP) are environmentally responsive polymers that exhibit phase transition behavior in response to various stimuli such as temperature, pH and irradiation. In this work, we focused on pH-responsive ELPs. It has been shown that pH value, configurations of ELPs, ELP concentration, and salt concentration can impact the phase transition behavior of pH-responsive ELPs. Quantitative models have been developed to engineer various linear ELPs, but there has not been any detailed study for engineering ionizable ELP with non-linear configurations. In this study, we designed, synthesized, and characterized pH-responsive ELPs with two different configurations. One is linear ELP, (GVGVPGEGVPGVGVP)12, and …

Novel On-Demand Droplet Generation For Selective Fluid Sample Extraction, Melinda Simon, Jeffrey Fisher, Melinda Simon, Abraham Lee

Faculty Publications

A novel microfluidic device enabling selective generation of droplets and encapsulation of targets is presented. Unlike conventional methods, the presented mechanism generates droplets with unique selectivity by utilizing a K-junction design. The K-junction is a modified version of the classic T-junction with an added leg that serves as the exit channel for waste. The dispersed phase fluid enters from one diagonal of the K and exits the other diagonal while the continuous phase travels in the straight leg of the K. The intersection forms an interface that allows the dispersed phase to be controllably injected through actuation of an elastomer …

Characterization Of Elastic-Like Polypeptide Micelles Using Capillary Viscometry, Sumit H. Kambow

ETD Archive

Elastin-like polypeptides (ELPs) are a part of the family of responsive polymers. These polymers can be made to respond to a wide variety of stimuli, including temperature, pH, salt, concentration, light, and solvent. Elastin-like polypeptides are soluble in water at low temperatures but they become hydrophobic and insoluble above their transition temperature. Elastin-like polypeptides, (GVGVP)40-foldon and (GVGVP)60-foldon, were expressed in bacterial system. These ELPs above their transition temperature, Tt, at low salt (< 45mM) and high pH (> pH 10) assemble into micelles where the hydrophobic tails phase separate in the interior of the micelle as an immiscible coacervate phase. The oligomerization domain termed as …

Characterization Of Elastin-Like Polypeptides Using Viscometry, Hamdan Noman Alanazi

ETD Archive

Elastin-like polypeptides (ELPs) are a class of polypeptide polymers that are gaining interest in various potential applications. These polymers are responsive to the changes in their environment by exhibiting conformational changes and aggregation. Monodisperse elastin-like polypeptides, (GVGVP)40, (GVGVP)40-foldon, and (GVGVP)60-foldon are made in bacterial expression system. An Ubbelohde capillary viscometer was set up to characterize the structural changes of these ELPs in phosphate buffered saline (PBS) solution. For the ELP-foldon, the relative viscosity measurements were utilized to calculate the intrinsic viscosities using Kraemer and Huggins equations. The known molecular weights of the ELPs and the experimentally determined intrinsic viscosities facilitated …

Thermal Analysis Of Poly(Desamino Arylates), Ali Cem Recber

Theses

The goal of this study is to better understand the thermal characteristics and molecular behavior of two poly(desaminotyrosyl arylates). These two polymers were chosen from a combinatorial library of polymers developed by changing the type and size of the two substitutable chain locations. TGA, DSC and TSC studies were conducted on Poly(12,10) and Poly(2,2) after the samples were exposed to various conditions. The TGA of Poly(12,10) shows low water uptake at 25° C, higher water uptake at 80°C. Water uptake for Poly(2,2) at 25°C is similar to Poly(12,10) at 80°C. The Thermally Stimulated Current analysis (TSC) results indicate a molecular …

Dimensional Study Of Desaminotyrosyl Polyarylates, Kalsank Vaishali Pai

Theses

Synthetic polymers have found widespread usage and acceptance in various areas of the medical device industry. The recognition that no polymeric biornaterials are truly biocompatible has led to the search for bioerodible materials with desirable biological and physical properties for use as tissue engineering scaffolds and to enable in-vivo devices. Several methodologies have been tried and tested to invent the "ideal" biopolymer. The ideal polymeric biomaterial would be one that offers a favorable response at both the cellular and the systemic level with minimum alteration to its mechanical properties and chemistry. The systematic investigation of process-structure-property space to determine the …

Laser Profilometry Of Polymeric Materials, Eduard A. Kulik, Patrick Calahan

Cells and Materials

Unlike the mechanical stylus profilometer, the laser profilometer does not damage the surface of soft materials. However, the accuracy of autofocusing of the laser profilometer is not always sensitive enough to discriminate the material/air interface from subsurface structures of semitransparent polymers. In the present study over ten polymeric surfaces were gold coated in order to investigate the effect of gold coating on the readings of a laser profilometer. Surface profiles of some polymeric materials became much smoother even if a very thing gold coating was applied to increase the reflection from the surface. It was concluded that a thin gold …

A Novel In Vitro Model To Study The Calcification Of Biomaterials, Q. Liu, J. Weng, J. G. C. Wolke, J. R. De Wijn, C. A. Van Blitterswijk

Cells and Materials

A novel in vitro model based on a solution mainly composed of sodium, calcium, chloride and phosphate ions, was developed to study the calcification of biomaterials at near physiological conditions. This model, due to its ability to quickly calcify the tested materials, is called Accelerated Calcification Solution (ACS). Polyactive ™ 30170, Polyactive™ 70/30 and its composites with nano-apatite were used as testing materials because of their known calcification behaviour. The results showed that Polyactive™ 70/30 and its composites could calcify in ACS in a relatively short period, while the polymer without filler failed to induce calcium phosphate precipitation in more …

Surface Modification Of Polymers To Permit Endothelial Cell Growth, C. James Kirkpatrick, Detlef Mueller-Schulte, Marc Roye, Guenter Hollweg, Claudia Gossen, Horst Richter, Christian Mittermayer

Cells and Materials

The interaction between endothelial cells (EC) and polymers has become relevant to medicine as a result of attempts to improve the biocompatibility of vascular prostheses. In man, endothelialization is minimal, so that vascular surgeons have attempted to pre-seed vascular grafts with autologous EC. The poor results of EC seeding of commonly used materials for vascular grafts, such as expanded polytetrafluoroethylene (ePTFE) or woven polyester (Dacron) has led to attempts to modify the surface of these and other polymers. Three principal modification techniques have been employed : 1. adsorption of bioactive molecules from applied solutions. Examples are fibronectin, collagen types I …