Resumen de L'enllaç disulfur com a eina per a la síntesi modular de revestiments (multi)funcionals inspirats en els musclos
This Thesis is part of a research line focus on the development of new functional materials based on catechol compounds for multiple applications. In particular, a new polymerisation strategy for catechol derivatives has been designed based on sulphur chemistry, which offers a higher degree of functionalisation and higher synthetic control over the structure of the resulting polymers than other reported strategies offer. Subsequently, these polymers have been used as (multi)functional coatings on both nanostructures and macrostructures. This project is multidisciplinary, because it includes a first part focused on the synthesis of several functional monomers and their corresponding polymers; a second part focus on materials’ field where different macro-/nanostructures (e.g. glass, metals, textiles, and mesoporous silica and magnetite nanoparticles (NPs)) have been coated to control their wettability; and a last biological part focus on the study of in vitro toxicity and cell internalisation of coated NPs.
Up to six catecholic molecules have been synthesised from the same symmetrical molecule, pentaerythritol tetrakis(3-mercaptopropionate), with different functionalities: polyethylene glycol (PEG) chains, fluorescent tags, and aliphatic and fluorinated chains. All of them have been polymerised under mild oxidative conditions using a solution of iodine in ethanol, forming disulphide bonds. At the end, mixtures of short oligomers (between 2 and 10 units) have been obtained and used to coat several substrates. For instance, mesoporous silica NPs have been coated with oligomers bearing PEG chains and fluorescein moieties, making them fluorescent and stable in aqueous media. These NPs have not appeared to be cytotoxic against SH-SY5Y cells with respect to control at any concentration used and have internalised into the nucleus of these cells after 6 h. Moreover, magnetite NPs have been coated with oligomers bearing PEG chains and post-functionalised with an aminoglucopyranose derivative (molecular fragment that would facilitate the crossing through the blood-brain barrier due to the presence of glucose’s receptors within this barrier) to build up model nanocarriers for therapeutic agents against illness that affect the central nervous system. Finally, with aliphatic and fluorinated derivatives, macroscopic surfaces, such as glass, metals and textiles, have been coated, making them hydrophobic. Particularly, aliphatic-coated cotton pieces have been used to separate mixtures of oil in water, and by using the deigned methodology, the wettability of treated glass and cotton surfaces has been controlled by coating them with mixtures of oligomers containing both aliphatic chains and fluorescein moieties.
To sum up, in this Doctoral Thesis a new versatile, flexible, and chemically modular strategy for polymerising catechol derivatives have been designed.
