AF4 as a passepartout technique for the characterization of nanosystems of medical interest

Nanomedicines (NMs) are therapeutic or diagnostic medicines with dimensions typically between 1 and 1000 nm. NMs have drawn attention due to their ability to improve therapeutic efficacy and reduce toxicity compared to traditional drugs. Despite progress, many NMs struggle to transition from development to clinical use due to challenges like carrier toxicity, instability, and complex quality control (QC). The diverse nature of NMs makes difficult to establish universal analytical methods. Asymmetrical Flow Field-Flow Fractionation (AF4) is a promising technique for separating and characterizing nanoparticles (NPs), polymers, and macromolecules in a wide array of analytical conditions. This research aims to explore the potential of AF4 as a passepartout technique in characterizing NMs during the various stages of their development. Chapter 1 provides an overview of the topic. Chapter 2 focuses on Polydopamine (PDA) nanosystems, widely used in fields like drug delivery due to their biocompatibility and degradability although its structural diversity remains poorly understood. A miniaturized form of AF4, combined with multiple detectors, identified two distinct species formed during PDA synthesis. This breakthrough highlighted the ability of the technique to select optimal PDA nanoforms for clinical use. Chapter 3 discusses antimicrobial NPs. Nanosilver-based antimicrobials, combined with PDA, show potential in combating bacterial resistance. AF4, in conjunction with light scattering and spectrophotometric detection, streamlined the synthesis, purification, and characterization of these NPs, therefore acting as an eco-friendly multi-purpose tool. Chapter 4 examines the behavior of magnetic NPs in biological environments, focusing on stability and protein binding. AF4 allowed to study real-time interactions between MNPs and human serum albumin, addressing key safety concerns. Chapter 5 finally focuses on peptide-based drugs and their aggregation states. AF4 was crucial in assessing stability of liraglutide to aggregation, providing accurate insights into potential aggregation phenomena, which is a vital factor for regulatory approval of its various formulations.