Biology and Biomimetic Materials Commons^™

Electrophoresis In Heterogeneous Hydrogels And Applications In Surface Patterning, Ning Ge

Theses and Dissertations--Mechanical and Aerospace Engineering

The creation of chemical micropatterns on surfaces makes it possible to add unique chemical functionality to surfaces, modifying properties such as wettability, or even adding the ability to selectively bind other molecules. The creation of biochemical surface patterning in particular is useful in a variety of fields including tissue engineering and highthroughput drug screening. There are many existing surface patterning techniques which focus on precise control over the patterned geometry, even down to submicron scale features, but they do not allow local control over chemical concentration. So the results are high resolution patterns with binary concentration. There are also existing …

Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell

CMC Senior Theses

Here, we present a method of gravity-drawing polydimethylsiloxane (PDMS) silicone fibers with application as fiber optics and as model foldamers. Beginning as a viscous liquid, PDMS is cured using heat until its measured viscosity reaches 4000 mPa•s. The semi-cured elastomer is then extruded through a tube furnace to produce thin (diameters on the order of hundred micrometers) filaments with scalable lengths. PDMS is biocompatible, gas-permeable, flexible, and hydrophobic. Additionally, the PDMS surface hydrophobicity can be modified via UV exposure, O2 plasma, and corona discharge. We demonstrate the patternibility (i.e patterns of hydrophobicity) of PDMS fibers, adding complexity to potential foldamer …

Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues, Samerender Nagam Hanumantharao

Dissertations, Master's Theses and Master's Reports

The mechanotransduction of cells is the intrinsic ability of cells to convert the mechanical signals provided by the surrounding matrix and other cells into biochemical signals that affect several distinct processes such as tumorigenesis, wound healing, and organ formation. The use of biomaterials as an artificial scaffold for cell attachment, differentiation and proliferation provides a tool to modulate and understand the mechanotransduction pathways, develop better in vitro models and clinical remedies. The effect of topographical cues and stiffness was investigated in fibroblasts using polycaprolactone (PCL)- Polyaniline (PANI) based scaffolds that were fabricated using a self-assembly method and electrospinning. Through this …

Molecular Dynamics Simulations Of Interaction Of Dna Nucleotides And Lignin Oligomers With Small Molecules And Interfaces, Xinjie Tong

LSU Doctoral Dissertations

Molecular dynamics (MD) simulations of interaction of DNA nucleotides with self-assembled monolayers (SAMs) provide valuable information that is critical to the development of a new DNA sequencing technique. We investigated the interactions and transport characteristics of mononucleotides moving through nanoslits with SAMs-covered surfaces. Our simulations focused on nanoslits in which the walls were composed of three different types of SAMs: methylformyl terminated, methyl terminated, and phenoxy terminated. The results demonstrated that the phenoxy terminated surfaces have the shortest required nanoslits length for nucleotides separation.

Using MD simulations, we also investigated the interaction of mono-lignin and oligo-lignols with lipid bilayers and …

Properties Of High Early-Strength Type V Cement Concrete For Rapid Repair, Nader Ghafoori, Matthew O. Maler, Meysam Najimi, Ariful Hasnat

Civil and Environmental Engineering and Construction Faculty Research

This study examines the suitability of ASTM Type V cement concrete for rapid repair applications. To this end, experimental results on transport and durability properties of high earlystrength concretes using ASTM Type V cement were compared with those of a more traditional cement used for rapid repair, i.e. Type III cement. A cement content of 445 kg/m3 (750 lb/yd3 ) was maintained for all studied concretes. The experimental program included compressive strength, absorption, rapid chloride migration, corrosion resistance, and mass loss due to freezing and thawing regimes. The results of this study revealed that use of Type III and V …

Investigation Of The Electrode Polarization Effect For Biosensor Applications, Anil Koklu

Mechanical Engineering Research Theses and Dissertations

My research focuses on electrokinetic transport. Particularly, in this dissertation, we focus on fabrication and testing of micro electrodes with nanostructured surfaces to minimize the electrode polarization (EP) effects for biosensor applications. In the first study, electrochemical deposition of gold nanoparticles on to planar gold electrodes was used to generate rough surfaces. Dendritic nanostructures that reduced EP up to two orders of magnitude was obtained by optimizing the deposition conditions. These structures also enhanced dielectrophoresis (DEP) response of our bio-chips, making them usable in physiological buffers. In further studies we discovered a universal scaling of EP in the frequency domain, …

Self-Healing Concrete Using Encapsulated Bacterial Spores In A Simulated Hot Subtropical Climate, Marwa Hassan, Jose Milla, Tyson Rupnow, Ahsennur Soysal

Publications

Bacterial concrete has become one of the most promising self-healing alternatives due to its capability to seal crack widths through microbial induced calcite precipitation (MICP). In this study, two bacterial strains were embedded at varying dosages (by weight of cement) in concrete. Beam specimens were used to identify the maximum crack-sealing efficiency, while cylinder samples were used to determine their effects on the intrinsic mechanical properties, as well as its stiffness recovery over time after inducing damage. The concrete specimens were cured in wet-dry cycles to determine their feasibility in Region 6. The results showed that the specimen groups with …

Novel Low Shear 3d Bioreactor For The Scaled Production Of High Purity Human Mesenchymal Stem Cells, Andrew Burns

KGI Theses and Dissertations

Human mesenchymal stem cells are an ideal candidate for stem cell therapies. They have been researched since the 1960’s and can differentiate into many desired functional cell types without undergoing teratogenesis. However, higher yields are needed for a marketable, successful stem cell therapy. To accomplish this, cells will have to be cultured to expand them to therapeutically relevant dosages for multiple patients. Bioreactor production is an ideal method to solve this problem.

The aim of this thesis is to test and validate a novel bioreactor for the cultivation of human mesenchymal stem cells. In this work, we investigate a novel …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi S. Patel

University Scholar Projects

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Left Atrial Model, Borna Sobati, Sarah Porello, Tess Pate

Biomedical Engineering

The objective is to produce an electrophysiological model of an adult human left atrium. This model will be used to test mapping probe catheters used for locating cardiac arrhythmias against current technology used in practice. Dr. Chris Porterfield requested this model and other physicians or probe catheter manufacturers may also use this product in the future. Dr. Porterfield also discussed the possibility of future senior project groups using the model as a bench test for designing new catheter tips. The model will precisely simulate electrical behaviors of the heart in normal as well as arrhythmic conditions. Ideally, the model will …

The Effect Of Defects And Surface Modification On Biomolecular Assembly And Transport, Haneen Martinez

Nanoscience and Microsystems ETDs

Nanoscale transport using the kinesin-microtubule (MT) biomolecular system has been successfully used in a wide range of nanotechnological applications including self-assembly, nanofluidic transport, and biosensing. Most of these applications use the ‘gliding motility geometry’, in which surface-adhered kinesin motors attach and propel MT filaments across the surface, a process driven by ATP hydrolysis. It has been demonstrated that active assembly facilitated by these biomolecular motors results in complex, non-equilibrium nanostructures currently unattainable through conventional self-assembly methods. In particular, MTs functionalized with biotin assemble into rings and spools upon introduction of streptavidin and/or streptavidin-coated nanoparticles. Upon closer examination of these structures …

Evaluation Of Guar Gum As A Novel Adsorbent, Philicia Geiser

Theses and Dissertations

Guar gum (GG) is a promising product increasingly used in a variety of industries. It is nontoxic, inexpensive, and biodegradable. This research evaluated novel approaches using GG as an adsorbent for aromatic organic water contaminants. The application of GG demonstrated some effectiveness against all contaminants tested. Two brands of GG were tested using 5 different GG treatment strategies. Various experiments demonstrated nearly complete removal of Allura Red dye, Brilliant Blue dye, Erythrosine B dye, Methylene Blue dye, Tartrazine dye, and 2,4-dinitrotoluene; additionally, 78% adsorption was observed for Fast Green dye. GG typically removed less than 10% of toluene, which rapidly …

Optimization Of Conditions For Production Of Mechanically Strong Suckerin Protein Hydrogels, Autumn Furniss

Williams Honors College, Honors Research Projects

Hydrogels are polymer networks with a large water content. Uses include biomedical applications like drug delivery, wound dressing, and more. Current natural hydrogels lack mechanical robustness. Squid ringed teeth (completely protein) have a modulus comparable to thermoplastics; adding this to hydrogels could improve modulus while maintaining biocompatibility.

Three experiments were performed: Hofmeister solubility study, SRT powder additive, and SRT aqueous solution. The first showed that LiCl solution without acetic acid dissolved the most SRT; overall LiCl dissolved more than all others. SRT as a powder additive increased the modulus of the hydrogels, however the error in the measurements make it …

Nanoharvesting And Delivery Of Bioactive Materials Using Engineered Silica Nanoparticles, Md Arif Khan

Theses and Dissertations--Chemical and Materials Engineering

Mesoporous silica nanoparticles (MSNPs) possess large surface areas and ample pore space that can be readily modified with specific functional groups for targeted binding of bioactive materials to be transported through cellular barriers. Engineered silica nanoparticles (ESNP) have been used extensively to deliver bio-active materials to target intracellular sites, including as non-viral vectors for nucleic acid (DNA/RNA) delivery such as for siRNA induced interference. The reverse process guided by the same principles is called “nanoharvesting”, where valuable biomolecules are carried out and separated from living and functioning organisms using nano-carriers. This dissertation focuses on ESNP design principles for both applications. …

Process-Property-Microstructure Relationships In Laser-Powder Bed Fusion Of 420 Stainless Steel., Subrata Deb Nath

Electronic Theses and Dissertations

Laser-powder bed fusion (L-PBF) is an additive manufacturing technique for fabricating metal components with complex design and customized features. However, only a limited number of materials have been widely studied using L-PBF. AISI 420 stainless steel, an alloy with a useful combination of high strength, hardness, and corrosion resistance, is an example of one such material where few L-PBF investigations have emerged to date. In this dissertation, L-PBF experiments were conducted using 420 stainless steel powders to understand the effects of chemical composition, particle size distribution and processing parameters on ensuing physical, mechanical and corrosion properties and microstructure in comparison …

A Systematic Investigation Of Condensation Heat Transfer Using Asymmetric Micro-Scale Surfaces, Emily Brown

LSU Master's Theses

Asymmetric surfaces been shown to inducing unidirectional motion in the Leidenfrost regime; however, very minimal research has been conducted to investigate whether these surface can enhance condensation through the same means. The investigation of heat transfer of ratchets in condensation is a relatively untapped area of study, specifically ratchets with superhydrophobic properties. Anticipated difficulty lies in creating surfaces features or coatings that retain the ratchets and can adequately sustain optimal wetting state of Cassie-Baxter required to improve heat transfer performance during condensation. This study serves to investigate whether ratchets are a feasible surface feature to enhance condensation heat transfer. First, …

Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found …

Application Of Nano-Plasmonics For Sers Bio-Detection And Photocatalysis In The Same Platform, Muhammad R. Shattique

Graduate Theses/Dissertations

Nano-biological systems interfacing nano-structured solid surfaces with biological compounds such as oligonucleotides or proteins are highly regarded as enabling materials for biosensing and biocatalysis applications. In particular, nanostructures of noble metals such as gold or silver, when exposed to light, exhibit a phenomenon known as surface plasmon resonance. When a proper metal nanostructure (plasmonic substrate) is exposed to light, very efficient absorption of incoming photons is possible, resulting in a buildup of localized high-energy regions, or “hot-spots”, where energetic carriers or “hot carriers” can be created. These hot-carriers can be used to catalyze desired chemical transformations in materials located nearby. …

Soft-Microrobotics: The Manipulation Of Alginate Artificial Cells, Samuel Sheckman

Mechanical Engineering Research Theses and Dissertations

In this work, the approach to the manipulation of alginate artificial cell soft-microrobots, both individually and in swarms is shown. Fabrication of these artificial cells were completed through centrifugation, producing large volumes of artificial cells, encapsulated with superparamagnetic iron oxide nanoparticles; these artificial cells can be then externally stimulated by an applied magnetic field. The construction of a Permeant Magnet Stage (PMS) was produced to manipulate the artificial cells individually and in swarms. The stage functionalizes the permanent magnet in the 2D xy-plane. Once the PMS was completed, Parallel self-assembly (Object Particle Computation) using swarms of artificial cells in complex …