Nanocomposites of PLA/ZnO nanofibers for medical applications: Antimicrobial effect, thermal, and mechanical behavior under cyclic stress

• Published in: Polymer engineering and science Vol. 62; no. 4; pp. 1147 - 1155
• Main Authors: Nonato, Renato C., Mei, Lucia H. I., Bonse, Baltus C., Leal, Claudenete V., Levy, Carlos E., Oliveira, Flavio A., Delarmelina, Camila, Duarte, Marta C. T., Morales, Ana R.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2022; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: 3D printing; Antiinfectives and antibacterials; antimicrobial; Antimicrobial agents; Biocompatibility; Biodegradability; Biopolymers; Body temperature; Coliforms; Composition; Degree of crystallinity; Dynamic mechanical analysis; E coli; electrospinning; Fatigue; Fatigue strength; Fatigue tests; Lactic acid; Mechanical properties; nanocomposite; Nanocomposites; Nanofibers; Polylactic acid; Properties; Salmonella; thermal properties; Three dimensional printing; Zinc oxide; Brazil
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.25913

The application of biodegradable and biocompatible polymer poly(lactic acid) (PLA) in the medical field has been widely studied. In this study, films of neat PLA and PLA containing 1 wt% ZnO nanofibers obtained by electrospinning (PLA/ZnO) were successfully molded by solvent‐cast three‐dimensional (3D) printing. Mechanical behavior was assessed by conventional dynamic mechanical analysis (DMA) and by adapting the equipment conditions to simulate a mechanical fatigue test at human body temperature—cyclic stress in isotherm at 36.5°C. DMA results showed that for temperatures above 30°C, the storage module of PLA/ZnO was higher when compared to neat PLA, and in the fatigue test, PLA/ZnO withstood more than 3600 cycles while neat PLA failed after an average of 1768 cycles. Differential scanning calorimetry (DSC) tests revealed that cyclic stress did not cause changes in the degree of crystallinity of the PLA. The microdilution and plating methods were applied to bacteria (Staphylococcus aureus, Salmonella, and Escherichia coli) and to yeast (Candida albicans) and revealed the antimicrobial effect of ZnO nanofibers and the PLA/ZnO composite. The antimicrobial activity and fatigue resistance of PLA/ZnO nanocomposites indicate that the material has potential for application in bone implants.