Wettability, Topography and Chemistry of Composite PLGA/CaP/Ti Scaffolds for Targeted Drug Delivery.

This work contributes to the understanding of an interplay between surface chemistry, morphology, and wettability properties, crucial for advancing biomaterial coatings in drug delivery systems. The surface properties of multilevel scaffolds, including a titanium frame, a calcium phosphate (CaP) coating and a poly(lactide-co-glycolide) (PLGA) layer are studied. It is shown that CaP coatings have complex internal morphologies with branched pore structures and spheroidal surface elements. A 5 wt.% PLGA modification, however, does not alter the structure, increasing the PLGA concentration to 8−10 wt.%, leading to the formation of a homogeneous polymer film, changing the porous structure and reducing the surface roughness. The FTIR spectra confirm the presence of various functional groups, correlating with changes in properties. A systematic analysis of the hydrophilic/hydrophobic nature, free surface energy, and surface roughness of pure CaP and pure PLGA surfaces as well as CaP/PLGA samples is given. The pure CaP coating and pure PLGA are found to be hydrophilic, with the water contact angles lower than 26° and 74°, respectively. An application of PLGA to the CaP coatings resulted in hydrophobization, with the water contact angles exceeding 94°. [ABSTRACT FROM AUTHOR]