Tissue engineering (TE) approaches often employ polymer-based scaffolds to provide support with a view to the improved regeneration of damaged tissues. The aim of this research was to develop a surface modification method for introducing chitosan as an antibacterial agent in both electrospun membranes and 3D printed poly-ε-caprolactone (PCL) scaffolds. The scaffolds were functionalized by grafting methacrylic acid N-hydroxysuccinimide ester (NHSMA) onto the surface after Ar-plasma/air activation. Subsequently, the newly-introduced NHS groups were used to couple with chitosan of various molecular weights (Mw). High Mw chitosan exhibited a better coverage of the surface as indicated by the higher N% detected by X-ray photoelectron spectroscopy (XPS) and the observations with either scanning electron microscopy (SEM)(for fibers) or Coomassie blue staining (for 3D-printed scaffolds). A lactate dehydrogenase assay (LDH) using L929 fibroblasts demonstrated the cell-adhesion and cell-viability capacity of the modified samples. The antibacterial properties against S. aureus ATCC 6538 and S. epidermidis ET13 revealed a slower bacterial growth rate on the surface of the chitosan modified scaffolds, regardless the chitosan Mw.

In this work, an equation for the prediction of the low pressure region of the water adsorption isotherms of activated carbons, based on their amount of surface groups, has been further developed in order to account for porous carbonaceous materials with an oxygen-rich surface chemistry. To attain this goal, highly hydrophilic carbon materials were selected and their surface chemistry was modified by several techniques (mainly thermal and plasma treatments) in order to obtain a series of samples with a surface oxygen content up to 45 wt. %. Then, their water sorption isotherms were measured and the amount of surface groups obtained by fitting them by the proposed equation was compared with the one resulting from direct X-ray photoelectron spectroscopy (XPS) measurements.Based on the obtained results, it seems that beyond a certain concentration of surface oxygen, there is a change in the sorption mechanism (from clustering to layering) and consequently, on the size of the water cluster formed before the micropore filling. These findings have allowed us to go a step further in the modelling of this part of the water sorption isotherms and to find a correlation between the surface oxygen content and the water cluster size.

We developed a uniform, transparent and low-roughness F4-TCNQ/MEK layer to controllably dope graphene with superior optical quality.

The use of graphene in optical and photonic applications has gained much attention in recent years.

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