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LSU Doctoral Dissertations

AFM

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Full-Text Articles in Physical Sciences and Mathematics

Nanoscale Studies Of Proteins And Thin Films Using Scanning Probe Microscopy, Zachary Lane Highland Jan 2017

Nanoscale Studies Of Proteins And Thin Films Using Scanning Probe Microscopy, Zachary Lane Highland

LSU Doctoral Dissertations

Nanostructures of organosilanes, thin metal films, and protein nanopatterns were prepared and analyzed with atomic force microscopy (AFM). Organosilanes with designed functional groups were used to selectively pattern green fluorescent protein at the nanoscale using protocols developed with particle lithography. Mesospheres are deposited onto a substrate to produce a surface mask. Organosilanes are deposited to form a matrix film surrounding nanopores for depositing proteins. The nanopatterns were characterized using AFM, after steps of particle lithography for directly visualizing surface changes. Studies with AFM also provide a compelling tool for teaching undergraduates to introduce concepts of nanoscience. An undergraduate laboratory was …


Investigating The Structure Of The Papain-Inhibitor Complex Using Spr And Nmr, Margaret Sara Thomasson Jan 2016

Investigating The Structure Of The Papain-Inhibitor Complex Using Spr And Nmr, Margaret Sara Thomasson

LSU Doctoral Dissertations

Cysteine proteases (CPs) are enzymes with a nucleophilic thiol in their active sites. Inhibitors of cysteine proteases (ICPs) occur naturally in bacterial pathogens and some protozoa. In parasites, ICPs are often virulence factors, contributing to the formation and survival of amastigotes within host cells. These amastigotes have higher CP activity, therefore making both ICPs and CPs potential drug targets. Despite great genetic variability, ICPs contain highly conserved structural features, including a series of defined loops that play a significant role in binding CPs. Papain, a CP from Carica papaya, complexes with ICP from Leishmania mexicana. Although the individual 3-D structures …


Chemically Patterned Surfaces As Test Platforms To Study Magnetic And Solvent-Responsive Properties At The Nanoscale: Investigations Using Scanning Probe Microscopy, Shalaka Kulkarni Jan 2015

Chemically Patterned Surfaces As Test Platforms To Study Magnetic And Solvent-Responsive Properties At The Nanoscale: Investigations Using Scanning Probe Microscopy, Shalaka Kulkarni

LSU Doctoral Dissertations

Chemically patterned surfaces were fabricated using a combination of molecular self-assembly and particle lithography to generate billions of nanostructures of organosilane self-assembled monolayers (SAMs). Monodisperse mesospheres were used as surface masks to prepare nanostructures on flat surfaces using the simple benchtop chemistry steps of mixing, centrifuging, evaporation, and drying. Periodic arrays of well-defined organosilane nanostructures serve as discrete surface sites for the selective deposition of polymers and magnetic nanoparticles.

In this dissertation, particle lithography approaches for surface patterning provide new directions for studying surface chemistry at the molecular-level using high resolution investigations with scanning probe microscopy (SPM). Atomic force microscopy …


Molecular-Level Investigations Combining Nanoscale Lithography And Atomic Force Microscopy, Chamarra Karmelia Saner Jan 2013

Molecular-Level Investigations Combining Nanoscale Lithography And Atomic Force Microscopy, Chamarra Karmelia Saner

LSU Doctoral Dissertations

In this dissertation, nanostructures of octadecyltrichlorosilane (OTS) and were prepared using particle lithography and evaluated using characterizations with atomic force microscopy (AFM). The nanostructures of OTS were used as a resist for patterning fibronectin, an extracellular matrix protein. Particle lithography provides a practical and reproducible approach to generate billions of nanostructures comprised of organic thin films or nanomaterials. A film of mesospheres can be applied as a surface mask to define the periodicity and size of nanopatterns using processes of self-assembly. A close-packed arrangement of mesospheres is produced spontaneously when monodisperse solutions of latex or silica are dried on a …


Scanning Probe Investigations Of The Surface Self-Assembly Of Organothiols And Organosilanes Using Nanoscale Lithography, Tian Tian Jan 2013

Scanning Probe Investigations Of The Surface Self-Assembly Of Organothiols And Organosilanes Using Nanoscale Lithography, Tian Tian

LSU Doctoral Dissertations

Particle lithography and scanning probe lithography were applied to study the kinetics and mechanisms of surface self-assembly processes. Organothiols on Au(111) and organosilane on Si(111) were chosen as model systems for investigations at the nanoscale using atomic force microscopy (AFM). Fundamental insight of structure/property interrelationships and understanding the properties of novel materials are critical for developments with molecular devices. Methods using an AFM probe for nanofabrication have been applied successfully to prepare sophisticated molecular architectures with high reproducibility and spatial precision. The established capabilities of AFM-based nanografting were reviewed for inscribing patterns of diverse composition, to generate complicated surface designs …


Application Of Scanning Probe Microscopy For New Physical Measurements And Studies Of Surface Chemical Reactions Of Materials At The Molecular Level, Stephanie Loletha Daniels Jan 2011

Application Of Scanning Probe Microscopy For New Physical Measurements And Studies Of Surface Chemical Reactions Of Materials At The Molecular Level, Stephanie Loletha Daniels

LSU Doctoral Dissertations

Scanning probe microscopy (SPM) provides unique capabilities for surface visualization and measurements that reach atomic and molecular dimensions. My research focus is directed toward applying and developing new measurements for analytical and surface chemistry with SPM. Two distinct goals based on studies with atomic force microscopy (AFM) will be described within this dissertation. The primary goal was to develop and apply a new AFM imaging mode for ultrasensitive measurements of the superparamagnetic properties of proteins. Magnetic sample modulation (MSM)-AFM, has capabilities to investigate and map the magnetic response of nanomaterials with unprecedented spatial resolution. The second goal was to apply …


Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune Jan 2010

Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune

LSU Doctoral Dissertations

Studies of the surface assembly and molecular organization of organic thin films were studied using scanning probe microscopy (SPM) and scanning probe lithography (SPL). Systems of organic thin films such as n-alkanethiols and pyridyl functionalized porphyrins were characterized at the molecular level, and measurements of the conductive properties of polythiophenes containing in-chain cobaltabisdicarbollides were accomplished. Understanding the self-organization and mechanisms of self-assembly of organic molecules provides fundamental insight for structure/property interrelationships. Investigations of the surface assembly of 5,10-diphenyl-15,20-di-pyridin-4-yl-porphyrin (DPP) on Au(111) were done using SPL methods of nanoshaving and nanografting. Automated computer designs were developed for nanofabrication to provide local …