Development of zinc oxide/hydroxyapatite/poly(D,L-lactic acid) fibrous scaffold for tissue engineering applications

Scaffolds based on polymeric fibers represent an engaging biomedical device due to their particular morphology and similarity with extracellular matrices. The biggest challenge to use fibrous materials in the biomedical field is related to their favorable platform for the adhesion of pathogenic microorganisms. Therefore, their optimum performance not only depends on their bioactive potential but also on their antimicrobial properties. The aim of this work was the design of antimicrobial (zinc oxide, ZnO) and bioactive (hydroxyapatite, Hap) fibrous materials using poly(D, L-lactic acid) (PDLLA) as the polymer fiber substrate. Fiber based composite scaffolds were developed using the Forcespinning® technique. For analysis purposes, the morphological, thermal, antimicrobial and biological properties of the fibrous hybrid system obtained at a concentration of 5 wt% of ZnO and 5 wt% of Hap were studied. The incorporation of the aforementioned nanoparticles (NPs) mixture in PDLLA led to an increase in viscosity and a pseudo-plastic tendency of the precursor solution, which caused an increase in fiber diameters and their dispersion of values. Small cavities and certain roughness were the main surface morphology observed on the fibers before and after NPs incorporation. The fiber thermal stability decreased due to the presence of the NPs. The antimicrobial properties of the hybrid fibrous scaffold presented a growth inhibition (GI) of 70 and 85% for E. coli and S. aureus strains, respectively. Concerning the osteoblast-cell compatibility, PDLLA and hybrid PDLLA scaffold showed low toxicity (cell viabilities above 80%), allowing cell growth inside its three-dimension structure and favorable cell morphology extended along the fibers. This behavior suggests a promising potential of this hybrid PDLLA scaffold for bone application.