Biocompatibility and degradation of PLA reinforced with tungsten disulfide nanotubes for 3D-printed bone scaffold

Advancements in bone tissue engineering have increased interest in 3D-printed scaffolds for bone regeneration. Polylactic acid (PLA), a biocompatible and biodegradable polyester, is a promising candidate for bone scaffold materials. Reinforcing PLA with inorganic nanotubes of tungsten disulfide (INT-WS₂) offers new possibilities for scaffold design. INT-WS₂ is an innovative material known for its chemical stability, non-toxicity, and favorable mechanical properties. Integrating PLA with INT-WS₂ marks a pioneering development in bone scaffold technology, providing a safer, more effective alternative to other nanofillers, such as TiO₂ nanoparticles and carbon nanotubes, which face challenges related to cytotoxicity and dispersion. This study adds an important aspect to the characterization of this material by investigating the cytocompatibility and hydrolytic degradation effects on 3D-printed samples of PLA reinforced with 0.5 wt% INT-WS₂. The samples are proposed as structurally suitable candidate for load-bearing 3D-printed bone scaffolds, with the femur chosen as the upper-limit mechanical benchmark. Controlled hydrolytic degradation of PLA/INT-WS₂ samples was conducted over 12 weeks under human-body simulated conditions. Results demonstrated that the material underwent bulk degradation while maintaining mass and surface hardness. Although the ultimate tensile strength progressively decreased to two-thirds of its initial value, potentially allowing gradual loading of the growing bone, it remained significantly higher than the maximum stress experienced by the human femur during normal walking. Furthermore, the PLA/INT-WS₂ nanocomposite exhibited non-toxic behavior, promoting cell viability and proliferation. Despite the need for a longer experiment to fully assess the degradation rate, these findings support PLA/INT-WS₂ as a promising candidate for tailored 3D-printed bone scaffolds designed for individual patients.