Responsive hydrogels applied in the biomedical area show great potential as synthetic extracellular matrix mimics and as host medium for cell growth. The hydrogels often lack the characteristic mechanical properties that are typically seen for natural gels. Here, we demonstrate the unique responsive and mechanical properties of hydrogels based on oligo(ethylene glycol) functionalized polyisocyanopeptides. These stiff helical polymers form gels upon warming at concentrations as low as 0.006 %-wt polymer, with materials properties almost identical to those of their intermediate filaments, a class of cytoskeletal proteins. Using a combination of macroscopic rheology and molecular force microscopy the hierarchical relationship between the macroscopic behaviour of theses peptide mimics has been correlated with the molecular parameters.

Stable helical polymers with a preferred handedness are compounds that offer intriguing characteristics. This review describes the progress in the synthesis of helical polyisocyanides and the investigations to determine their structural properties, such as helical pitch and handedness, by spectroscopic measurements and high resolution AFM. This review is not intended to be comprehensive; its purpose is to highlight recent studies that allow a better understanding of the main aspects of helical polyisocyanides.

A new class of antibody-functionalized, semi-flexible and filamentous polymers (diameter 5-10 nm, length $200 nm) with a controlled persistence length, a high degree of stereoregularity and the potential for multiple simultaneous receptor interactions has been developed. We have decorated these highly controlled, semi-stiff polymers with T cell activating anti-CD3 antibodies and analyzed their application potential as simple synthetic mimics of dendritic cells (sDCs). Our sDCs do not only activate T cells at significantly lower concentrations than free antibodies or rigid sphere-like counterparts (PLGA particles) but also induce a more robust T cell response. Our novel design further yields sDCs that are biocompatible and non-toxic. The observed increased efficacy highlights the importance of architectural flexibility and multivalency for modulating T cell response and cellular function in general.

Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.

Dye-sensitized photoelectrochemical cells (DSPECs) are a promising approach to produce solar fuels, e.g. by reduction of protons to molecular hydrogen. Here, we present functional NiO photocathodes sensitized with covalent organic dye-catalyst assemblies integrating a robust cobalt tetraazamacrocyclic complex. This catalyst proved to be decisive to improve the stability of these systems, hydrogen being produced with a 26-fold increase in turnover numbers compared to similar photocathodes based on a cobaloxime catalyst, all other conditions being strictly identical otherwise. Transient absorption spectroelectrochemical (TA-SEC) measurements observed the catalytically competent Co I state in a functional dye-sensitized photocathode, with a lifetime of up to > 1 ms, comparable to the timescale of catalysis. They also unveiled the lack of efficiency of the thermally activated electron transfer from the reduced dye to the catalyst, which firstly limits the photocurrent density for hydrogen production. A second consequence is the accumulation of photogenerated charges on the acceptor side of the dye, ultimately leading to its degradation, as observed in operando and post-operando characterization of the system. This study thus provides tracks to improve the performances of hydrogen-evolving dye-sensitized photocathodes toward their integration into functional DSPECs.