Biophysics Commons^™

Endogenous Light In The Brain: Investigating Sources, Propagation, And State-Dependent Emission, Emre Cicek

Theses and Dissertations (Comprehensive)

Ultraweak photon emission (UPE), and by extension light, has long been thought to be a modality of communication in nature. Prior studies have already identified that UPE can depend on cell type and can be used to discern between malignant and benign cells. However, besides theoretical models, not much effort has been made to identify possible biological structures that would allow for light to be used as a method of communication in the human body. According to the framework set by Shannon’s Information Theory, for communication to be possible at minimum a transmitter, a transmission channel, and a receiver are …

Sec-Saxs And Sans Analyses Of The Talin•Vinculin Complex, Gilbert Reyes

Dissertations, Theses, and Capstone Projects

Focal adhesions (FA) are integrin-based cell-matrix adhesion sites composed of adaptor proteins that facilitate the generation of traction forces important for biological functions such as cell migration, embryo development, wound healing, tissue organization and stability, and immune responses. Mature FA are observed when both autoinhibited multi-domain scaffolding protein talin and membrane-cytoskeletal protein vinculin are activated and interact thus promoting the assembly and function of FA. While research has resolved truncated sections of autoinhibited talin and recruitment of vinculin due to mechanotransduction that exposes cryptic vinculin binding sites (VBS), little is known about the global modifications of full length talin in …

Modeling Kinetics Of 5-Aminolevulinic Acid-Induced Protoporphyrin Ix Accumulation For Optimal Photodynamic Therapy, Priscilla Melebor

Graduate Masters Theses

Photodynamic therapy (PDT) is a minimally invasive treatment that uses light-activated photosensitizers to selectively destroy diseased tissue through the generation of reactive oxygen species. However, conventional in vitro models often fail to accurately reproduce the pharmacokinetics of photosensitizer accumulation and clearance observed in vivo. This study investigated protoporphyrin IX (PpIX) accumulation following 5-aminolevulinic acid (ALA) exposure under physiologically relevant conditions using two-dimensional (2D) monolayers and three-dimensional (3D) spheroids. By comparing continuous ALA exposure with transient exposure followed by ALA washout, this work provides a more biologically relevant framework for studying PpIX kinetics and optimizing photodynamic therapy.

Three-Dimensional Cell And Nuclear Geometries Inform Tissue Level Fluid Mechanics During Epithelial Remodeling, Liam Joseph Russell

Electronic Theses and Dissertations

During epithelial remodeling, mechanical and molecular programs must coordinate to drive the cell shape changes that enable new tissue topologies. Dynamic morphogenesis requires epithelia to preferentially exhibit solid- or fluidlike properties depending on developmental and biophysical constraints. Convergent extension in the Drosophila germband epithelium is one such remodeling event, during which the lateral ectoderm lengthens by two-fold along the primary body axis while concomitantly shortening orthogonally. This process is an incredibly dynamic and attractable system for studying tissue morphogenesis mechanics in vivo.

Germband extension is driven by oriented cell intercalation through T1 transitions, where cells directionally interdigitate with one another …

Biophysical Insights Into A Cryptic Ligand Site In The Hydrophobic Core Of Human Pcna, Alexis N. Dispensa, Sharon N, Greenwood, Jason Yang, Daniel E. Logatto, James Fusco, E. Railey White, Roderic G. Eckenhoff, Zhiwei Liu, Brian P. Weiser

Department of Anesthesiology Faculty Papers

Proteins contain small pockets that form due to imperfections in residue packing or the rotational and conformational movement of amino acids. In this work, we used the fluorescent probe 1-aminoanthracene (AMA) to detect a small ligand pocket in the hydrophobic core of human proliferating cell nuclear antigen (PCNA), which is a critical protein for DNA replication and repair. Fluorescence measurements of AMA reported that the core of PCNA had a dielectric constant (ε) of 4, which was very apolar and similar to cyclohexane (ε = 2). Protein mutagenesis, photoaffinity labeling, and molecular dynamics simulations localized the binding site for AMA …

Nanoscale Morphological Perturbations Of Lipid Membranes Induced By Membrane Active Peptides, Yasith Sandeepa Indigahawela Gamage

USF Tampa Graduate Theses and Dissertations

Membrane-active peptides (MAPs) are a diverse group of biologically relevant molecules that induce nanoscale modulations during their interactions with cell membranes. Understanding the precise mechanism by which these MAPs perturb or modulate the cell membranes is a cornerstone of membrane biophysics, as it facilitates rational design of useful therapeutics. That is, if we have the knowledge to determine what the peptide can do, how selective it is, or how toxic it might be, we can optimize them and design new peptide therapeutics such as for antimicrobial, anticancer, or drug-delivery applications. In general, MAPs can be categorized into two classes based …

Investigating Quinclorac Binding To Human Serum Albumin Using Spectroscopy And Molecular Docking, Le Nguyen, L. Hicks, L. Jodoin, S. Carby, D. S. Sanford, D. Benavides, A. Mishra, R. Yadav

Journal of the Arkansas Academy of Science

Human serum albumin (HSA) is the most abundant plasma protein and serves as a major transporter and reservoir for a wide range of endogenous ligands, including fatty acids, heme, bilirubin, prostaglandins, and metal ions, as well as numerous exogenous compounds, such as pharmaceuticals. HSA is a 66 kDa monomeric, multidomain protein containing two principal ligand-binding sites, Sudlow sites I and II. Sudlow site I contains Trp214, the sole tryptophan residue in HSA, whose intrinsic fluorescence provides a sensitive probe for studying ligand–protein interactions.

In this study, the interaction between HSA and the persistent organochlorine herbicide quinclorac (QNC) was investigated using …

A Computational Micropatterning Approach To Study Caveolae And Protein Localization In Vascular Biology, Andrew B. Grespin

Electronic Theses and Dissertations

Caveolae are specialized, flask-shaped membrane invaginations highly expressed in endothelium and dysregulated in atherosclerosis. Caveolae play a central role in buffering membrane tension, yet the principles governing their spatial organization remain elusive. Thus, we sought to generate the most comprehensive and systematic analysis of blood vessel caveolar spatial organization. However, cell culturing, the backbone of human-focused biological research, does not standardly do well to model physiologically relevant cell behaviors such as migration or polarity-based tissue formation, particularly for punctate proteins and structures like caveolae. Micropatterns are cell-adhesive shapes that biophysically confine cell(s) to a user defined geometry which stereotype organelle …

Developing A High-Resolution Off-Axis Common-Mode Digital Holographic Microscope, Lucy Cook

University Honors Theses

Off-axis digital holographic microscopy (DHM) is a powerful tool for 3D, non-invasive live-cell tracking without moving parts. However, traditional setups face an inherent dilemma: split-path interferometers offer high spatial resolution but poor temporal stability, while more stable common-mode configurations are historically limited to lower numerical aperture (NA) regimes. This thesis bridges that gap by scaling a common-mode DHM architecture into a high-resolution benchtop instrument featuring NA = 0.65 objectives, paired with a high-power 520 nm laser source to combat transmission losses and sustain imaging frame rates across an expanded optical footprint. We map the multi-variable design space required to satisfy …

Supramolecular Assembly In Short Peptide Systems For Selective Metabolite Recognition And Drug Nanoencapsulation, Maithreyi Ramakrishnan

Dissertations, Theses, and Capstone Projects

Short peptides can form adaptive supramolecular assemblies, and understanding how minimal sequences organize around neurometabolites or hydrophobic cancer drugs enables the rational design of functional materials. This thesis combines molecular dynamics with experimental validation to establish design rules linking peptide sequence to emergent structure and function. Chapter 1 outlines the molecular determinants governing peptide assembly. Chapter 2 reviews computational workflows that reveal sequence-dependent conformations and supramolecular organization. Chapter 3 applies these principles to Dynamic Peptide Libraries which identify tetrapeptides that selectively interact with neurometabolites. Chapter 4 extends the same interaction-driven framework to design tryptophan-rich pentapeptides that co-assemble with kinase inhibitors …

Mapping Nucleosome Stability: Linking Oncogenic Structural Alterations To Long-Range Allosteric Communication, Augustine C. Onyema

Dissertations, Theses, and Capstone Projects

The nucleosome core particle (NCP) is essential for chromatin structure and function, serving as the fundamental unit of eukaryotic chromatin. Oncogenic mutations in core histones disrupt chromatin dynamics, altering DNA repair and transcription processes. How DNA communicates with histones, and how this information propagates through the histone, has been suggested to be a cooperative process. Here, I investigate the molecular consequences of two mutations, H2BE76K and H4R92T, using 36 µs of all-atom molecular dynamics simulations on Anton2. I also characterize the kinetic correlation within histone/DNA domains via conditional activity (CONDACT) using the dihedral angle as our degrees of …

The Heterogeneous Response Of Astrocytes In Different Brain Regions Under Metabolic Stress, Pawan Kumar Thapaliya

USF Tampa Graduate Theses and Dissertations

Astrocytes play a central role in maintaining ionic homeostasis, neurotransmitter clearance, and brain en-ergy metabolism. Their excitability, reflected in activity-evoked intracellular sodium (Na+, [Na+]i) and calcium (Ca2+,[Ca+]i) dynamics, is increasingly recognized as a critical determinant of neuronal function and vulnerability, particularly under metabolic stress. Despite their importance, the mechanisms underlying astrocytic ionic signaling and its regional heterogeneity remain incompletely understood. In this thesis, I developed detailed computational and biophysical models to investigate astrocytic Na+ and Ca2+ dynamics, their bioenergetic consequences, and the roles of key ion transporters under physiological and metabolically stressed conditions, validating the models against experi- mental data. …

Microtubules In Breast Cancer: Exploring The Α/Β-Tubulin Toggle Switch And Its Implications In Human Breast Cancer, Annemarie Ianos

Student Theses and Dissertations

Microtubules, composed of a/b-tubulin heterodimers, play a central role in breast cancer tumor growth by polymerizing, leading to metastasis and depolymerizing, contributing to proliferation. Human enzymes protein kinase Ca (PKC-a) and cyclin-dependent kinase 1 (Cdk-1) mediate phosphorylation at sites a:Ser165 and b:Ser172, respectively, influencing the growth of microtubules. It is possible that alternating phosphorylation at these sites contribute to an a/b-tubulin “toggle switch” that mediates microtubule instability and tumor growth.

The project investigates the influence of the toggle switch model on microtubule stability by determining the impact of mutants (a:S165D, a:S165N, a:S165S_P, b:S172S_P and a:S165S_P/b:S172S …

Ai×Life 2026: Advances In Computational Biology Across Scales For Life & Health Sciences, Suma Mohan S., Devika N. T., Pranavathiyani G.

Conference Proceedings

Book of Abstracts of the International Conference, AIxLife 2026: Advances in Computational Biology Across Scales for Life & Health Sciences, held on 17–18 April 2026, SASTRA Deemed to be University, Thanjavur, Tamil Nadu, INDIA 

About the Conference

Conventional computational biology laid the foundation for biological data analysis through statistical models, algorithms, and curated databases, enabling insights into genes, proteins, and pathways. Today, the integration of artificial intelligence, spanning machine learning, deep learning, and large language models (LLMs) is driving a transformative shift across biological scales, from atomic and molecular interactions to pathways, cellular systems, organisms, and populations.

AI-powered approaches …

Understanding Tlr3 Immune Response Activation In Cryptosporidium Parvum And Cryspovirus Pathogenesis, Surayya Hudayberganova

Biochemistry and Molecular Biology

Cryptosporidiosis is a serious gastrointestinal illness caused by a protozoan parasite known as Cryptosporidium. It is particularly dangerous for malnourished children and those with compromised immune systems. My research focuses on the Toll-like receptor 3 (TLR3) response to the Cryptosporidium parvum infection, specifically in the presence of the parasite’s viral mutualist named cryspovirus (CSpV1). Results using research methodologies like ELISA and RT-qPCR have indicated that TLR3 expression increases during the infection process of Cryptosporidium parvum (C. parvum). Furthermore, one intriguing observation concluded during this study suggests that administering the TLR3-specific inhibitor CU-CPT4a to infected cells drastically decreased this activation. This …

Sensing Rna’S Conformation With A Solid-State Nanopore Device At Various Ph And Temperature, Haopeng Li

Graduate Theses and Dissertations

This study uses solid-state nanopore technology to investigate the stability and dynamics of RNA molecules under thermal stress and pH fluctuations. Two distinct mRNA samples were analyzed: (1) heat shock protein (HSP)-encoding mRNA extracted from Sulfolobus solfataricus P2, a thermophilic archaeon inhabiting extreme environments such as geothermal sulfuric hot springs (pH < 4, temperature range: 65–90°C), and (2) total RNA extracted from White Leghorn chickens, which thrive under standard physiological conditions. ΦX174 virion single-stranded DNA (ssDNA) were included as a comparative reference. Nanopores, fabricated in silicon nitride membranes, were used to electrically characterize the structural properties of individual RNA molecules in solution, close to their native environments. The nanopore membrane separates two chambers containing salt buffer solution, where ionic current is the primary measurement parameter. When a voltage bias is applied across the membrane, ion flow and an ionic current can be measured. Charged RNA molecules driven translocation through the nanopore induces pore resistance changes, resulting in detectable current blockade events. Variations in these events provide insights into RNA secondary structure and conformational dynamics. By systematically altering pH and temperature, this study elucidates the effects of environmental stressors on RNA stability and structural integrity. The findings reveal distinct responses between thermophilic HSP-encoding mRNA and mesophilic RNA, underscoring the adaptive mechanisms of thermophilic RNA under extreme conditions. These results contribute to a better understanding of RNA behavior under stress and establish a foundation for future applications in RNA-based diagnostics and biotechnology development.

Membrane Organization Of Rheb And Rhoa: Roles In Function And Allosteric Druggability, Chase M. Hutchins

Dissertations and Theses (Open Access)

Small GTPases of the Ras superfamily are membrane-bound molecular switches that regulate nearly all major cellular processes, and their dysregulation drives cancers, neurological disorders, and metabolic diseases. While anchored to cellular membranes, the catalytic domains of small GTPases undergo orientation dynamics, adopting distinct configurations that can occlude or expose effector-binding surfaces and modulate signaling output. These dynamics have been characterized in the Ras oncoproteins, but whether they extend across the superfamily and influence allosteric druggability has remained unknown.

In this dissertation, I address these questions through Rheb and RhoA, two small GTPases with complementary differences in subfamily lineage, membrane localization, …

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

Design And Optimization Of Peptide Inhibitors Targeting Kinesin: Molecular Modeling Studies And Virtual Screening For Therapeutic Candidate Development, Maraf Mbah Bake

Open Access Theses & Dissertations

Kinesins are ATP-driven molecular motors essential for intracellular transport and mitotic spindle assembly, and their mechanochemical behavior has been extensively characterized through computational tools. The first project reviews decades of advances in molecular dynamic simulations, including all-atom and coarse-grained molecular dynamics, Markov state models, Brownian dynamics, and free-energy approaches, which have collectively deepened our understanding of conformational transitions, microtubule-binding interfaces, and ligand interactions, especially for the mitotic motor Eg5. The second review examines the rapid emergence of quantum computing as a transformative technology for drug discovery, highlighting key historical milestones, recent progress in hybrid quantum-classical algorithms, quantum-enhanced docking, and quantum …

G-Quadruplex Dna-Driven Genomic Instability Under Ber Loss, Addison Belick, Claryssa Gutierrez, Joslynn Rosas, Andrea Vargas

Posters - 2026

Base Excision Repair (BER) is a cellular tool that can repair damaged DNA (Hindi et al., 2022, Cellular and Molecular Life Sciences). G-quadruplexes (G4s) are unique 4-stranded structures in DNA or RNA that are rich in guanine (Gray et al., 2023, Nat. Chem. Biol). The purpose of this study is to understand whether BER contributes to the removal of G4s in DNA. This will determine if the BER-deficient yeast is more sensitive to treatment with G4-binding drugs than the BER-proficient yeast. We will replace the APN1 gene in the yeast genome with the URA3 gene, because the wild type yeast …