Carbon-based materials are poised to be an important class of 21st century materials, for bio-medical, bio-electronic, and bio-sensing applications. Diamond and polymers are two examples of carbon-based materials of high interest to the bio-materials community. Diamond, in its conductive form, can be used as an electrochemical bio-sensor, whilst its nanoparticle form is considered a non-inflammatory platform to deliver drugs or to grow neuronal cells. Polymers, especially when chemically modified, have been used extensively in biological environments, from anti-microbial use to drug delivery. The large-scale use of either material for biological use is limited by two factors: ease of chemical modification and the paucity of knowledge of their surface chemistry in aqueous media. This thesis addresses aspects of both these issues. The first study reported is an in situ study of the adsorption dynamics of an exemplar globular protein (bovine serum albumin, BSA) on nanodiamond using the relatively novel quartz crystal microbalance with dissipation (QCM-D) technique. For the first time, QCM-D enabled the detailed study of protein dynamics (i.e. kinetics, viscoelastic properties, overlayer structure, etc.) onto nanodiamond thin films having various surface chemistry and roughness. The dynamics of protein adsorption is found to be sensitive to surface chemistry at all stages of adsorption, but it is only sensitive to surface roughness during initial adsorption phases. Our understanding of the nanodiamond-biology interface is enhanced by this study, and it suggests that QCM-D is useful for the study of the surface chemistry of nanoparticle forms of inorganic materials. A second study concerns a novel surface functionalization scheme, based on carbene and azo-coupling chemistry, which has been recently introduced as a practical, facile method for modifying the surfaces of polymers. Using modern surface characterization techniques, it is demonstrated that a chemical linker can be attached to polystyrene surfaces using carbene-based chemistry, and that further chemical functionality can be added to this chemical linker via an azo-coupling reaction. In situ studies of protein dynamics at these interfaces were conducted using QCM-D, thus enabling a link between specific protein behaviour and the polymer surface chemical termination chemistry to be made. A third area of study of investigates the use of diamond electrodes as a bio-sensor for dopamine under physiological conditions. For these conditions, ascorbic acid interferes with the dopamine oxidation signal, in ways that render the two signals irresolvable. Various modifications are used in attempts to reduce this interference, including: small and large cathodic treatments, grafting of electro-active polymers, addition of carbon nanotubes, and hydrogen plasma treatment. Those modifications leading to the hydrogen-termination of diamond are shown to work the best. Notably, hydrogen plasma treatment effects the complete electrochemical separation of dopamine and ascorbic acid at a diamond electrode. This is the first time this has been accomplished without adding non-diamond materials to the diamond electrode surface.

S’han dipositat capes primes d’hidrogel per tal de modificar les propietats superficials i millorar el comportament dels biomaterials. Dues de les tècniques de deposició química en fase vapor més comunes s’han estudiat per poder dur a terme aquestes modificacions. La deposició química foto-iniciada en fase vapor (piCVD) és un mètode simple, ràpid i no agressiu que permet depositari films d’hidrogel. És un mètode que s’inicia a la superfície de la mostra i que permet recobrir de manera homogènia superfícies tridimensionals com és el cas de les micro-partícules. El piCVD ofereix un ventall molt ampli d’hidrogels amb capacitat d’absorbir aigua, incorporant co-monòmers amb diferents propietats. Els hidrogels poden ser dissenyats perquè la reactivitat es localitzi a nivell superficial, millorant d’aquesta manera la funcionalització química dels hidrogels. Tanmateix, un nou mètode s’ha utilitzat per micro-estructurar les superfícies durant la deposició via piCVD per obtenir hidrogels amb comportaments especials. Els hidrogels termo-sensibles s’han obtingut via deposició química iniciada en fase vapor (iCVD). S’ha desenvolupat una llibreria d’hidrogels termo-sensibles, els quals exhibeixen una temperatura de transició molt marcada. La microbalança de quars amb dissipació (QCM-D) s’ha fet servir per analitzar la transició d’aquests films. La combinació de les propietats que ofereixen els films termo-sensibles dona la possibilitat de dissenyar una plataforma per prevenir la formació de biofilms. / Se han depositado capas delgadas de hidrogel para lamodificación superficial y mejora del comportamiento de los biomateriales. Dos de las técnicasmás comunes de deposición química en fase vapor se han estudiado para llevar a cabo estas modificaciones. La deposición química foto-iniciada en fase vapor (piCVD) es un método simple, rápido y no agresivo que permite depositar films de hidrogel. Es un método que se inicia en la superficie de la muestra y que permite recubrir de manera homogénea superficies tridimensionales como es el caso de las micro-partículas. El piCVD ofrece un abanico muy amplio de hidrogeles con capacidad de absorber agua, incorporando co-monomeros con diferentes propiedades. Los hidrogeles se pueden diseñar para que la reactividad se localice a nivel superficial, mejorando de esta manera la funcionalización química de los hidrogeles. Así mismo, un nuevo método se ha utilizado para micro-estructurar las superficies durante la deposición vía piCVD para obtener hidrogeles con comportamientos especiales. Los hidrogeles termo-sensibles se han obtenido vía deposición química iniciada en fase vapor (iCVD). Se ha desarrollado una librería de hidrogeles termo-sensibles, los cuales exhiben una temperatura de transición muy marcada. La microbalanza de cuarzo con disipación (QCM-D) se ha utilizado para analizar la transición de este film. La combinación de las propiedades que ofrecen los films termo-sensibles da la posibilidad de diseñar una plataforma para prevenir la formación de biofilms. / Thin hydrogel films have been deposited to modify surface properties and improve biomaterials performance. Two of the most common chemical vapor deposition techniques have been studied to carry out these modifications. Photo-initiated chemical vapor deposition piCVD has been developed as a simple, not aggressive and easy method for the deposition of thin hydrogel films. This method follows a versatile surface-driven reaction process that allows homogeneous coating of both 2D and 3D geometries, such as microspheres. piCVD offers the possibility to fabricate a wide range of swellable thin films, incorporating co-monomers with different properties, such as amine-reactivity, suitable for further modification. The hydrogels can be designed by nano-confining the reactivity to the near surface region, improving the chemical functionality of hydrogels. In addition, a new method to create micro-patterned surfaces can be applied during piCVD deposition to design surfaces having special behavior. Thermo-responsive thin hydrogel films have also been obtained via initiated chemical vapor deposition (iCVD). A library of thermo-sensitive films exhibiting controlled lower critical solution temperatures (LCST) has been generated. Quartz crystal microbalance with dissipation analysis has been used to analyze the phase-transition of these films. The intrinsic properties of thermo-sensitive hydrogels, such as tunable surface hydrophilicity or release of film-entrapped molecules, open the possibility to design systems for controlling biofilm formation.