Physical Sciences and Mathematics Commons^™

Synthesis, Structure-Activity And Mechanism Studies Of Poly(Guanylurea)S Against Mycobacteria, Michelle M. Miranda

FIU Electronic Theses and Dissertations

Tuberculosis (TB) continues to be a serious threat worldwide, especially in developing countries. Current first-line treatment for TB infections is a multidrug regimen for 4-9 months; if not taken as prescribed, drug-resistant TB can emerge. Novel drugs with unconventional targets are warranted to lessen the lengthy and four-drug treatment. Antimicrobial polymers mimicking naturally occurring antimicrobial peptides (AMPs) have gained much attention due to their enzymatic stability, tunability, cost-effectiveness, and unique mode of action - directly or indirectly - on bacterial membrane. However, selectivity and toxicity have limited their biological applications. Previously, our group synthesized a novel class of antimicrobial polymers, …

Synthesis Of Phenyl Carbamoylated Guanidine Functionalized Chitosan, Eduardo Hernandez Requejo

FIU Electronic Theses and Dissertations

The lack of solubility of the chitosan in organic solvents hinders its potential for chemical modifications. For this reason, it was hypothesized that the insertion of the phenyl carbamoylated guanidine moiety could lead to increased solubility in DMSO and new potential modifications and uses.

This research involved the synthesis of S-methyl phenyl carbamoylated guanidine (SMPCG) starting from the commercially available S-methyl isothiourea. This was followed by the reaction of the SMPCG with chitosan to yield phenyl carbamoylated guanidine functionalized chitosan (PCGCs) with a degree of substitution of 14%.

The chitosan derivative is fully soluble in DMSO and partially in DMF. …

Modified Guanidine-Containing Polymers For Intracellular Protein Delivery, Alfonso Barrios

FIU Electronic Theses and Dissertations

Protein-based therapeutics have gained significant attention for treating or curing various diseases, especially those untreatable by small molecule-drugs. Despite their widespread success and adoption, the cellular membrane remains a major obstacle for proteins to reach the inner compartments of the cell and have had limited applicability spanning only extracellular targets. Consequently, the efficient intracellular delivery of proteins offers tremendous potential to reach new, unexplored, and otherwise “undruggable” targets. Acknowledging the therapeutic need, research efforts aimed at facilitating the delivery of proteins using polymer-based nanoparticles have emerged.

Guanidine-containing polymers provide a promising platform to address the common hurdles associated with protein …

Understanding The Functional Group-Dependent Self-Assembly And Cellular Entry Of Cationic Conjugated Polymer Nanoparticles, Prakash Manandhar

FIU Electronic Theses and Dissertations

Highly fluorescent conjugated polymers (CPs) are an important class of biomaterials used for various biological applications including labelling, sensing, and delivery of biological substances. Synthetic versatility and tunable emission make CPs a superior class of biomaterials. Understanding the structure-function relationship of CPs plays a vital role in designing high performing biomaterials. The cationic CPs are self-assembled to conjugated polymer nanoparticles (CPNs) in an aqueous environment due to their amphiphilicity. The physical and biophysical properties of CPNs are highly dependent on the chemical functionality and backbone structure of CPs. Modulation of the surface property and backbone structure of CPNs play an …

Hybrid Polymer Electrolyte For Lithium-Oxygen Battery Application, Amir Chamaani

FIU Electronic Theses and Dissertations

The transition from fossil fuels to renewable resources has created more demand for energy storage devices. Lithium-oxygen (Li-O₂) batteries have attracted much attention due to their high theoretical energy densities. They, however, are still in their infancy and several fundamental challenges remain to be addressed. Advanced analytical techniques have revealed that all components of a Li-O₂ battery undergo undesirable degradation during discharge/charge cycling, contributing to reduced cyclability. Despite many attempts to minimize the anode and cathode degradation, the electrolyte remains as the leading cause for rapid capacity fading and poor cyclability in Li-O₂ batteries. In this …

Conjugated Polymer-Based Biomaterials Through Controlled Self-Assembly, Megan Twomey

FIU Electronic Theses and Dissertations

Synthetic polymeric materials have gained significant use as biological materials (biomaterials) in biomedical and pharmaceutical applications. As a result, a demand for well-defined polymers with tunable properties has emerged. The synthetic versatility of polymeric biomaterials allows the opportunity to understand the structure-property relationship of materials and their cellular interactions. A novel class of polymeric biomaterials are conjugated polymers (CPs), which possess desirable physicochemical and excellent photophysical properties, including inherent fluorescence. The synthetic versatility of CPs allows easy modification of the conjugated backbone to tune emission and side chain structures to adjust biocompatibility through increased water solubility, controlled biodegradability, and incorporation …

Synthesis And Characterization Of Photochromic Copolymers Containing 3-Indolylfulgides/Indolylfulgimides, Changjun Fan

FIU Electronic Theses and Dissertations

Fulgides and fulgimides are important organic photochromic compounds and can switch between the open forms and the closed forms with light. The 3-indolylfulgides and 3-indolylfulgimides exhibit promising photochromic properties and have great potential in optical memory devices, optical switches and biosensors. Copolymers containing 3-indolylfulgides/indolylfulgimides synthesized via free radical polymerizations increase conformation changes and allow the photochromic compounds to be uniformly distributed in the polymer matrix.

A trifluoromethyl 3-indolylfulgide and two trifluoromethyl 3-indolylfulgimides with one or two polymerizable N-stryryl group(s) were prepared. Copolymerization with methyl methacrylate provided two linear copolymers or a cross-linked copolymer. The properties of the monomeric fulgide/fulgimides …

Synthetic Approaches To Flexible Fluorescent Conjugated Polymers, Tereza Vokata

FIU Electronic Theses and Dissertations

Conjugated polymers (CPs) are intrinsically fluorescent materials that have been used for various biological applications including imaging, sensing, and delivery of biologically active substances. The synthetic control over flexibility and biodegradability of these materials aids the understanding of the structure-function relationships among the photophysical properties, the self-assembly behaviors of the corresponding conjugated polymer nanoparticles (CPNs), and the cellular behaviors of CPNs, such as toxicity, cellular uptake mechanisms, and sub-cellular localization patterns.

Synthetic approaches towards two classes of flexible CPs with well-preserved fluorescent properties are described. The synthesis of flexible poly(p-phenylenebutadiynylene)s (PPBs) uses competing Sonogashira and Glaser coupling reactions …