New photo-curable polymers suitable for 3D printing are here provided, exhibiting a mechanical light-responsivity upon laser irradiation. Azobenzene moieties are employed both as a dye component in the 3DP and as active groups, providing photo-mechanical responsivity. The incorporation of azobenzene units into polymeric matrices allows a reversible and controllable change of the Young's modulus of 3D printed micrometric structures.

An alternative route to plasmon-controlled fluorescence for improving the detection of fluorescence is proposed. In place of a metallic layer, a suitable silicon-based one-dimensional photonic crystal is used to generate a Bloch surface waves-coupled emission from a thin polymeric layer decorated with a fluorescent dye. Fluorescent radiation coupled to Bloch surface waves is strongly polarized and directional, with an angular divergence of 0.3° corresponding to a spectral bandwidth of 3 nm. Within this range, an overall signal enhancement of a factor larger than 500 is obtained as compared to a conventional glass substrate thanks to an additional enhancement mechanism based on dyes excitation via Bloch surface waves.

Azopolymers are known to exhibit a strong light responsivity known as athermal photofluidization. Although the underlying physics is still under debate, athermal photofluidization has been demonstrated to trigger mass-migration according to the polarization of a proper illumination light. Here, a polymer blend is proposed wherein a commercial azo-polyelectrolyte is mixed with a passive polymer. The blend is patterned as an array of micro-pillars that are individually exposed to visible laser illumination. Thanks to the interplay between the two blend components, a reversible and controlled deformation of the micro-pillars by periodically tuning the laser polarization in time is demonstrated. A reduced mobility of the azo-compound allows to repeatibly elongate and rotate micro-pillars along specific directions, with no significant material flow outisde the initial volume and no significant degradation of the structure morphology over several cycles. The proposed work suggests new degrees of freedom in controlling the mechanical features of micro-patterned light-responsive materials that can be usefully exploited in many application fields.

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Ag nanoparticles synthesized on porous silicon samples were studied and applied as substrates for surface‐enhanced Raman scattering (SERS). The metallic nanostructures prepared by immersion plating were characterized by UV–Vis reflectance spectroscopy and scanning electron microscopy. SERS activity of the substrates was tested using Cyanine dye 1,3,3,1′,3′,3′‐esamethyl‐5,5′‐dimethoxyindodicarbocyanine iodide (Cy5‐OCH3) as a probe molecule. The Raman spectra obtained for different excitation wavelengths indicate amplifications ascribed to plasmonic resonances with an enhancement factor up to 107. CGIYRLRS peptides were chemisorbed on the Ag nanoparticles with the plasmonic resonance tuned at the excitation energy. Such oligopeptides were used as baits for a specific polyclonal antibody. The overall Raman enhancement allowed to evidence a good selectivity to the target analyte as required by most of the SERS applications on biological assays. Copyright © 2011 John Wiley & Sons, Ltd.