Chemical modification of <scp>PLA</scp> for the design of <scp>3D</scp> printed nanocomposite scaffolds with enhanced degradability for bone tissue engineering
Giovanni Dal Poggetto, Ugo D’Amora, Alfredo Ronca, Maria Grazia Raucci, Alessandra Soriente, Giovanna Gomez d’Ayala, Paola Laurienzo
Abstract
Abstract In this study, 3D printing technology is used to develop nanocomposite scaffolds based on polylactic acid (PLA) and hydroxyapatite (HA). PLA was functionalized with itaconic anhydride (PLA f ) via radical grafting to improve affinity with the inorganic nanofiller and accelerate hydrolytic degradation. Fourier‐transform infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopies confirmed the occurrence of chemical functionalization. Preliminary characterization of films of PLA, PLA f and relative nanocomposites through water contact angle measurements highlighted an increase of wettability for PLA f , due to the hydrophilic groups grafted onto polymer chain. Thermal analysis showed an increase of glass transition temperature ( T g ) in PLA f nanocomposites, likely due to enhanced matrix‐nanoparticle interactions. Scanning electron microscopy (SEM) analysis revealed more defined and homogeneous fibers for PLA f ‐HA5 and PLA f ‐HA10, meanwhile results from compression tests indicated improved processability and enhanced mechanical properties of nanocomposite PLA f ‐based scaffolds, as evidenced by increased values of Young modulus. Hydrolytic degradation studies in Phosphate Buffered Saline (PBS) solution showed greater weight loss and molecular weight decrease for PLA f , PLA f ‐HA5, and PLA f ‐HA10, suggesting faster degradation due to increased hydrophilicity. Biological tests with human Mesenchymal Stem Cells (hMSCs) demonstrated that all scaffolds promoted cell proliferation, with PLA f ‐HA formulations showing higher effect on cellular behavior in terms of cell growth and alkaline phosphatase (ALP) levels, indicating that chemical functionalization improves cell attachment, proliferation and early osteogenic differentiation. Highlights Functionalization of PLA enhances hydrophilicity and HA affinity. Nanocomposite scaffolds based on PLA f are successfully developed by 3D printing. PLA functionalization enhances ink printability, making more uniform structures. PLA f ‐based scaffolds exhibit an accelerated hydrolytic degradation PLA f ‐HA scaffolds support cell adhesion and early osteogenic differentiation.