Molecular Sensing by Nanoporous Crystalline Polymers

Chemical sensors are generally based on the integration of suitable sensitive layers and transducing mechanisms. Although inorganic porous materials can be effective, there is significant interest in the use of polymeric materials because of their easy fabrication process, lower costs and mechanical flexibility. However, porous polymeric absorbents are generally amorphous and hence present poor molecular selectivity and undesired changes of mechanical properties as a consequence of large analyte uptake. In this contribution the structure, properties and some possible applications of sensing polymeric films based on nanoporous crystalline phases, which exhibit all identical nanopores, will be reviewed. The main advantages of crystalline nanoporous polymeric materials with respect to their amorphous counterparts are, besides a higher selectivity, the ability to maintain their physical state as well as geometry, even after large guest uptake (up to 10–15 wt%), and the possibility to control guest diffusivity by controlling the orientation of the host polymeric crystalline phase. The final section of the review also describes the ability of suitable polymeric films to act as chirality sensors, i.e., to sense and memorize the presence of non-racemic volatile organic compounds

Self Assembling and Coordination of Water Nano-Layers On Polymer Coated Long Period Gratings: Toward New Perspectives for Cation Detection

In this work, polymeric coated Long Period Gratings (LPGs) working in transition mode have been used to monitor the coordination and self assembling of water nano-layers (typical thicknesses range in few tens of nanometers) providing new scenarios in chemical sensing applications. In particular, nano-scale layers (∼320nm) of semicrystalline syndiotactic and amorphous atactic polystyrene (sPS and aPS), have been deposited by dip-coating onto LPGs to tune the devices at the transition point. Experimental results demonstrate the polymers capability to orient water molecules in proximity of their surfaces. The sPS and aPS interactions with water have been continuously monitored and then compared demonstrating the higher capability of the crystalline phase of sPS to orient water nano-layers. Moreover, the high sensitivity of the coated LPGs was used to monitor the effect of disorder induced on the interfacial water molecular arrangement by different cations (sodium, Na+, potassium, K+, and calcium, Ca2+, ions) depending on their size and electrical charge. Experimental results show for the first time that, thanks to the water-polymer interaction, sPS coated LPGs could be successfully employed as high sensitivity cation sensors. In fact, the monitoring of the disorder induced by cations on the coordinated water layer leads to high sensitivities, in terms of detected RI change for unitary variation of concentration (∼7.80 · 10−4RIU · mM−1 for Na+ ions, ∼9.00 · 10−4RIU · mM−1 for K+ ions, and ∼1.07 · 10−3RIU · mM−1 for Ca2+ ions)

Molecular and Immune Biomarkers for Cutaneous Melanoma: Current Status and Future Prospects

Advances in the genomic, molecular and immunological make-up of melanoma allowed the development of novel targeted therapy and of immunotherapy, leading to changes in the paradigm of therapeutic interventions and improvement of patients’ overall survival. Nevertheless, the mechanisms regulating either the responsiveness or the resistance of melanoma patients to therapies are still mostly unknown. The development of either the combinations or of the sequential treatment of different agents has been investigated but without a strongly molecularly motivated rationale. The need for robust biomarkers to predict patients’ responsiveness to defined therapies and for their stratification is still unmet. Progress in immunological assays and genomic techniques as long as improvement in designing and performing studies monitoring the expression of these markers along with the evolution of the disease allowed to identify candidate biomarkers. However, none of them achieved a definitive role in predicting patients’ clinical outcomes. Along this line, the cross-talk of melanoma cells with tumor microenvironment plays an important role in the evolution of the disease and needs to be considered in light of the role of predictive biomarkers. The overview of the relationship between the molecular basis of melanoma and targeted therapies is provided in this review, highlighting the benefit for clinical responses and the limitations. Moreover, the role of different candidate biomarkers is described together with the technical approaches for their identification. The provided evidence shows that progress has been achieved in understanding the molecular basis of melanoma and in designing advanced therapeutic strategies. Nevertheless, the molecular determinants of melanoma and their role as biomarkers predicting patients’ responsiveness to therapies warrant further investigation with the vision of developing more effective precision medicine