In recent times, biomolecular sensing to recognize genetic fragments and proteins is spurring unprecedented interest as a diagnostic protocol for cancer and infectious diseases. Significant efforts have been made to design nanomaterials able to control the light–matter interaction at the single nanometer scale, where genes and proteins bind specifically to receptors. Here, we numerically show how the interface between a chiral metasurface and hyperbolic metamaterials can enable both high sensitivity and specificity for low-molecular-weight nucleic acids and proteins. As we have recently reported, hyperbolic dispersion metamaterials allow molecular biorecognition with extreme sensitivity because of coupled and highly confined plasmon polaritons. Specificity is almost exclusively achieved by receptor–ligand interaction at the in-plane sensing surface. Interestingly, an adapted out-of-plane chiral metasurface enables three key functionalities of the hyperbolic metamaterial sensor. Computational effort reveals that helicoidal metasurfaces can act as (i) efficient diffractive elements to excite surface and bulk plasmon polaritons; (ii) out-of-plane sensing branches to reduce the diffusion limit and increase the sensing surface; and (iii) biorecognition assay also via circular dichroism and chiral selectivity.

A nanoplatform for simultaneous cellular imaging, and photodynamic and photothermal therapies has been designed and realized by embedding a purposely synthesized highly luminescent water soluble iridium(iii) compound into gold core-silica shell nanoparticles. These multifunctionalities arise mainly from the photophysical properties of the cyclometalated complex: (i) the heavy atom promotes, through excited triplet state formation, energy transfer processes towards molecular oxygen, with the generation of O (photodynamic effect); (ii) the overlap of the iridium(iii) complex emission band with the plasmonic resonance of gold nanostructures allows excitation energy transfer towards the metallic core (photothermal effect); (iii) the remarkable iridium(iii) complex luminescence feature, which is preserved despite energy transfer processes, makes the whole system an efficient luminescent bio-probe (imaging). Photophysical and photothermal investigations have been carried out, whereas in vitro photo-cytotoxicity tests have been performed on human glioblastoma cells (U87MG), highlighting significant cancer cell death at a very low photosensitizer concentration (<0.5 μM), by means of a synergistic photodynamic and photothermal effect.

The in vitro biological activity towards the MDA‐MB‐231 triple‐negative breast cancer cell line of two different series of anionic Pt(II) organometallic complexes was tested. For the first time, cytotoxic activity of anionic Pt(II) complexes has been observed. The anionic compounds of general formula NBu4[(C^N)Pt(O^O)], where (C^N) represents the cyclometalated form of 2‐phenylpyridine (H(PhPy)), 2‐thienylpyridine (H(Thpy)) or 2‐benzo[h]quinoline (H(Bzq)), feature two different (O^O) chelated ligands: tetrabromocatechol [BrCat]2− (1–3) or alizarine [Aliz]2− (4–6). Complexes 1–6 displayed a significant cytotoxic effect against the studied cell line (IC50 range of 1.9–52.8 μM). For BrCat‐containing complexes 1–3, the biological activity was independent of the nature of the coordinated (C^N) ligand. In contrast, in the case of 4–6, the cytotoxicity (significantly high for 4) was concomitantly induced by the presence of either the PhPy or the [Aliz]2− ligand. Since complexes 1–6 are emissive in solution, the potential use of 4 as a theranostic agent was investigated using confocal analysis. The fluorescence signal from MDA‐MB‐231 cells incubated with 4 indicated the localization of the compound into the cytosol region.

This paper concerns the coloring kinetics of electrochromic films obtained by dispersing viologen molecules in a thermoplastic polyacrylate matrix. The experimental data show that the oxygen molecules, which are originally dissolved as ubiquitous impurities in film chemical precursors, and are not eliminated during the film preparation, play a relevant role with respect to the speed of the electrochromic response in the coloring stage. The presence of oxygen can speed up the electrochromic response of the viologen cations or slow it down, depending on the degree of polymerization of the plastic matrix. In stiffer films oxygen accelerates the electrochromic response, while the contrary occurs in less stiff films. A theoretical model of the viologen kinetic electrochromic response has been developed to justify the experimental findings. This takes into account the possible electron exchange reactions with the oxygen molecules. A coherent interpretation of the experimental data has been obtained on the basis of this model.

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