Bioinspired and Biomimetic Micro/nanoparticles for Medical Applications

Abstract

Nature, and in particular the human body, offers countless inspiration sources. Translating its unique properties to synthetic materials has been the driving force of several studies up to today. Biomimetic and bioinspired micro/nanoparticles represent remarkable tools for this aim; however, since the complexity of biological systems, different features and attributes, such as size, shape, and surface properties, need to be evaluated._x000D_ The aim of this thesis is to develop a set of several biomimetic and bioinspired particles to address different biomedical problems currently affecting public health. Three main topics have been explored in this thesis._x000D_ First, an innovative system has been proposed as a new class of vaccine for bacteria that would represent a precious aid by limiting the spread of the increasing antibiotic resistance. For this, biocompatible polylactic acid microparticles have been developed to reproduce bacteria morphologies; the anisotropic shape of bacteria was evaluated as a biomimetic key factor for the specific stimulation of the immune system. Inspired by Pseudomonas aeruginosa, the combination of its structural properties, such as size and shape, with its immunogenicity, obtained by using antigens, has allowed achieving a significant immune activation in an in vivo model._x000D_ Secondly, powerful therapeutic and theragnostic tools have been proposed for their employment in the fight against cancer. Polymeric particles were combined with bioinspired magnetic nanocubes, and microparticles displaying an ellipsoidal shape, like magnetotactic bacteria, or spherical nanoparticles possessing a liquid core, were separately studied. The responsiveness of both types of particles under the influence of an external magnetic field was evaluated; in the case of spherical nanoparticles, in combination with light responsiveness, it was employed for thermal treatment and nanothermometry, and in the ellipsoidal one, for rotational stimulation._x000D_ Finally, neuromelanin-like nanoparticles have been designed as excellent dopamine delivery systems with unique advantages for Parkinson’s disease treatment. Supramolecular interaction and metal-ligand coordination have been exploited to develop two different systems, primarily constituted by dopamine. Iron was used as the metal node in both cases due to its biocompatibility and possible use as a contrast agent in magnetic resonance imaging. Outstanding amounts of dopamine were successfully encapsulated with non-covalent bonding, allowing its release. The drug delivery efficiency was further exploited by studying an innovative administration route, the intranasal, in vitro or in vivo.

Date of Award	5 May 2023
Original language	English
Supervisor	Claudio Roscini . (Director) & Daniel Ruiz Molina (Director)