Fibrous Structures Fabricated from Polylactic Acid and Nanofibrillated Chitosan/Zinc Oxide Nanoparticles

Hypothesis: 

Nowadays, the use of mixtures of natural and synthetic polymers in the production of biological scaffolds has been considered by researchers because of their ability to achieve the desired properties.

Nanofibers from polylactic acid (PLA) and nanofibrillated chitosan/zinc oxide nanoparticles (CS/ZnO) with three different blend ratios of 1:1, 2:1 and 1:0 were fabricated by electrospinning method. In order to reduce the number of experiments and thus reduce the cost of materials and time, nine different experiments were performed using Taguchi test design method with three factors: PLA concentration (PLA 7, 9 and 11% by wt), CS/ZnO concentration (5, 10 and 20% by wt) and three different CS/ZnO ratios of 1:1, 2:1 and 1:0. The contact angle and morphology of the produced scaffolds were evaluated using scanning electron microscopy (SEM).

The results of scanning electron microscopy showed that with increasing PLA concentration, the beads and spindle-like morphologies are lost and the fibers are almost smooth and uniform. The results showed that by increasing the CS/ZnO concentration from 5% to 20%, the diameter of nanofibers first decreased and then slightly increased. The contact angle of fabricated samples decreased with increasing CS/ZnO concentration from 5% to 10%. Also from the samples obtained by Taguchi method, nanofiber sample containing PLA (7%, CS/ZnO 2: 1) with CS/ZnO concentration of 10%, due to having a smaller diameter (345±30 nm), very thin structure and lower contact angle (101°) was reported as the optimal sample. The contact angle, morphology and surface roughness for the optimum sample were examined and the surface roughness for the optimal sample was about 178 nm. Cell culture studies on the optimal sample was successfully performed.