Synthesis of Multifunctional Nano and Micro-Structures for the Specific Isolation and Recovery of Biomarkers From Biological Fluids and Multifunctional Materials for Light/Energy Conversion

Abstract

One of the two main research topics this study explores is the isolation and purification of proteins and peptides, specifically small molecular weight biomolecules, as biomarkers. The second research topic involves synthesizing multifunctional magnetic and conductive materials for light-enhanced absorption in energy conversion processes.The primary objective of the first topic is to develop further a chromatographic concept that enables the separation and purification of peptides and biomolecules at a preparative scale by incorporating simultaneous specific adsorption and size exclusion using preparative polysaccharide matrices modified with permeation control polymers. This has been accomplished by grafting on chromatographic matrices two different heterogeneous ligands: one, a polymer, for this project, polyethylene glycol that, after a grafted density, permits the permeation of only certain molecular size range compounds, and a second one, a ligand with specific affinity, that preferentially binds target biomolecules of that specific molecular size range that could cross the restricted polymer barrier. Some of these chromatography hydrogels consisted of specific chelators with immobilized metal ion affinity chromatography (IMAC) and ion exchange chromatography groups, as well as hydrogen bond chromatography moieties. These restricted-access media were implemented into the gels by attaching two different molecular weights of polyethylene glycol (m-PEG), 2 kDa or 5 kDa. These gels, with specific adsorption types and varying sizes and densities of PEG, enable the separation of large molecules, such as proteins (primarily albumin and glycoproteins), from smaller molecules, including peptides and amino acids. The methodology in this project successfully separated amino acid derivatives, such as n-tyrosine, breakdown products, including creatinine, and small proteins, like myoglobin. Of specific relevance was the isolation and separation of the endogenous peptide fragments angiotensin (I, II, and 1-7), which can serve as biomarkers for the onset of COVID-19. Regarding the second topic, the main objective was to synthesize micro and nanoparticles with magnetic and conductive properties that, once modified or coated with functional groups, for example, with polydopamine, polysaccharides, polyaniline, (PEDOT: PSS), and metal ions have characteristic light adsorption such as black body light adsorption properties, light conversion to heat for thermal ablation applications. Several cellulose and agarose derivatives were magnetized with iron oxides, and the resulting materials exhibit relatively low reflectance properties, acting as black body structures. Magnetic nanoparticles were coated with agarose and further modified with chelating agents, producing materials with different reflective indices and colors, as well as specific thermal ablation characteristics when they bind metal ions. Magnetic nanoparticles coated with dopamine produced materials with chelating properties, but most relevant were the black body reflectance characteristics and their effective thermal ablation properties.