Design and bioapplication of nanointerfaces based on conducting polymers
- Autores: María del Mar Pérez Madrigal
- Directores de la Tesis: Carlos Alemán Llansó (dir. tes.), Elaine Armelin (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2015
- Idioma: inglés
- Tribunal Calificador de la Tesis: Jordi Puiggalí Bellalta (presid.), Eric A. Perpète (secret.), Catherine Michaux (voc.), Giovanni Marletta (voc.), Carmen Ocal Garcia (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Polímeros y Biopolímeros
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
This Thesis reports the fabrication and characterization of interfaces based on conducting polymers (CPs), which are designed with at least one dimension in the nanometric scale, for bioapplications such as scaffolds for promoting electro-active tissue regeneration, drug delivery systems or passive ion transport membranes. In particular, the development of such platforms is addressed to overcome CPs limitations without compromising their electrochemical and electrical properties. Special attention is placed on evaluating those properties that are known to determine cell-biointerface interactions (i.e. surface chemistry, topology and mechanical features) in addition to biocompatibility and biodegradability. Concretely, CP-based biointerfaces are designed as ultra-thin free-standing nanomembranes (FsNM), fibrous substrates or electropolymerized interfaces. In the first approach, spin-coating is used to prepare robust and flexible nanofilms by blending a chemically synthesized PTh derivative (P3TMA), which is soluble in THF, CHCl3 and DMSO, with an insulating polymer (i.e. polyester (PE44) or thermoplastic polyurethane (TPU)), which is crucial to provide mechanical integrity to P3TMA. Fully characterization of the resulting FsNM reveals that both systems, P3TMA:PE44 and TPU:P3TMA interfaces, retain features coming from each of the homopolymers: electrochemical activity and electrical response on the one hand, and biodegradability on the other. Moreover, they behave as potent cellular biointerfaces because they are biocompatible, electrobioactive and adequate substrates for type I collagen adsorption. Secondly, P3TMA is further used to obtain hybrid fibrous scaffolds. In this case, polylactic acid (PLA) and a poly-urea derivative (PEU-co-PEA) are chosen as biodegradable polymers. After the optimization of the electrospinning process, a study is carried out to investigate the electrochemical properties (electroactivity and electrostability) of both PLA:P3TMAand PEU-co-PEA:P3TMA hybrid samples, and their bioapplication. P3TMA displays a good doping level, and retains its electrochemical features in the hybrid fibrous samples, which are electroactive and electrostable. Again, P3TMA improves the cellular proliferation of cells cultured on the hybrid fibrous interfaces, thus enabling their use as suitable scaffolds for cell regeneration. Furthermore, PLA:P3TMA 2:1 fibrous interface can perform as a drug-delivery platform since it combines suitable wetting behaviour, biocompatibility and good electrical features. Drug-loaded matrices with TCS, CHX or CIP are antibacterial active, and thus the drug is feasible to be released from the fibrous biointerface by electrical stimulation. Finally, CP-based biointerfaces are prepared by electrochemical polymerization adopting specific strategies. Hence, Omp2a, an outer membrane protein which forms trimeric pores, is entrapped in a poly(N-methylpyrrole) (PNMPy) matrix, preserving its native structure, which ensures its operative and functional state as passive ion channel. Similarly, a bioactive platform is prepared based on the co-electropolymerization of a specially synthesized bis-thienyl monomer, AzbT, which contains carboxyl and Schiff base functionalities, and 2,2':5',2''-therthiophene (Th3). Such interfaces display good optical and electrochemical properties depending on the AzbT:Th3 molar ratio in the electrpolymerization medium. Furthermore, the copolymer with the highest AzbT content shows enhanced cell adhesion and proliferation results, with cells cultured on their surface homogeneously spread. Such behaviour has been interpreted as the combination effect of the minor release of harmful Th3 monomer entrapped into the polymeric matrix and the presence of the AzbT's distinctive groups.
