A Quantitative Structure-Activity Relationship (QSAR) of coumarins by genetic algorithms employing physicochemical, topological, lipophilic and electronic descriptors was performed. We have used experimental antioxidant activities of specific coumarin derivatives against the DPPH· radical molecule. Molecular descriptors such as Randic Path/Walk, hydrophilic factor and chemical hardness were selected to propose a mathematical model. We obtained a linear correlation with R2 = 96.65 and Q LOO2 = 93.14 values. The evaluation of the predictive ability of the model was performed by applying the Q ASYM2, $\hat r^2 $ and Δr m2 methods. Fukui functions were calculated here for coumarin derivatives in order to delve into the mechanics by which they work as primary antioxidants. We also investigated xanthine oxidase inhibition with these coumarins by molecular docking. Our results show that hydrophobic, electrostatic and hydrogen bond interactions are crucial in the inhibition of xanthine oxidase by coumarins.

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The application of polymers as medical devices has steadily increased in almost all medical fields because of the versatility of these materials. Thus, research has focused both on the development of more appropriate materials for specific situations and on the modification of already useful materials for the improvement of their intrinsic properties. Modifications on this kind of materials have increased their potential uses by adapting their mechanical properties to specific needs. Moreover, biocompatibility of the polymeric materials has been improved by the inclusion of certain functional groups, providing responses to physical and chemical stimuli present in physiological conditions.Until recently, one of the most worrying problems in hospitals has been infections derived from medical devices usage. Typically, this kind of infections was handled with the use of prophylactic and therapeutic treatments with 'classic' (low-molecular weight) antimicrobial agents. This strategy has been effective in most patients suffering from nosocomial infections. However, it has the disadvantage of substantially increasing the probability of antimicrobial-resistant pathogens appearance, which continue to be especially dangerous in hospital environments (Cohen et al., 2017; World Health Organization, n.d.;Zegers et al., 2017). Additionally, due to

The modification of medical devices is an area that has attracted a lot of attention in recent years; particularly, those developments which search to modify existing devices to render them antimicrobial. Most of these modifications involve at least two stages (modification of the base material with a polymer graft and immobilization of an antimicrobial agent) which are both time-consuming and complicate synthetic procedures; therefore, as an improvement, this project sought to produce antimicrobial silicone (PDMS) in a single step. Using gamma radiation as both an energy source for polymerization initiation and as a source of reducing agents in solution, PDMS was simultaneously grafted with acrylic acid and ethylene glycol dimethacrylate (AAc:EGDMA) while producing antimicrobial silver nanoparticles (AgNPs) onto the surface of the material. To obtain reproducible materials, experimental variables such as the effect of the dose, the intensity of radiation, and the concentration of the silver salt were evaluated, finding the optimal reaction conditions to obtain materials with valuable properties. The characterization of the material was performed using electronic microscopy and spectroscopic techniques such as 13C-CPMAS-SS-NMR and FTIR. Finally, these materials demonstrated good antimicrobial activity against S. aureus while retaining good cell viabilities (above 90%) for fibroblasts BALB/3T3.

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