Water has a key role in the functioning of all biological systems, it mediates many biochemical reactions, as well as other biological activities such as material biocompatibility. Water is often considered as an inert solvent, however at the molecular level, it shows different behavior when sorbed onto surfaces like polymeric implants. Three states of water have been recognized: non-freezable water, which does not freeze even at −100 °C; intermediate water, which freezes below 0 °C; and, free water, which freezes at 0 °C like bulk water. This review describes the different states of water and the techniques for their identification and quantification, and analyzes their relationship with hemocompatibility in polymer surfaces. Intermediate water content higher than 3 wt % is related to better hemocompatibility for poly(ethylene glycol), poly(meth)acrylates, aliphatic carbonyls, and poly(lactic-co-glycolic acid) surfaces. Therefore, characterizing water states in addition to water content is key for polymer selection and material design for medical applications.

The process of disinfection of wastewater must use friendly materials with the environment that achieve the inhibition of bacterial growth, aiming to improve the quality of the water. In this study, electrospun nanocomposites CS (chitosan)/AgNPs (silver nanoparticles) was developed for wastewater disinfection through filtration. First, AgNPs were synthesized by a green synthesis method using aloe vera ( Aloe Barbadensis Miller ) extract as a reducing agent, and AgNO ₃ as metal precursor. AgNPs were characterized by UV-Vis spectroscopy with a SPR band at 420 nm. Transmission Electron Microscopy (TEM) demonstrates the formation of semispherical AgNPs with a diameter ca. 16 nm. The nanocomposites fibers CS/AgNPs were analyzed by scanning electron microscopy (SEM), with the presence of uniform fibers (diameter ca. 120 nm) and embedded AgNPs, determined by EDS and elemental mapping. Surface topography of CS/AgNPs fibers was evaluated by Atomic Force Microscopy (AFM), where the surface roughness of fibers is increased with the NPs content. Finally, the antibacterial activity (AA) of CS/AgNPs nanocomposites was evaluated against S. aureus and P. aeruginosa during 1 and 2 h of contact, obtaining an AA of 90 % in CS/AgNPs-2 mM after 2 h with P. aeruginosa . The fabrication of electrospun nanocomposites with silver nanoparticles represents a platform to the fabrication of multifunctional polymer membranes for wastewater disinfection.