3D-printed bioactive scaffolds for bone regeneration bearing carbon dots for bioimaging purposes

Abstract

Additive manufacturing, also known as 3D-printing, has been successfully employed to create novel bioactive scaffolds incorporating carbon dots for bioimaging purposes. Fused filament fabrication technique (FFF) was used to print a hybrid poly-lactic acid (PLA)-based filament bearing bioactive material, suited for hydroxyapatite (HAp) development, as well as carbon dots which by virtue of their strong luminescence could support an optical characterization of the composite, thus, its regenerative stages. This technique using FFF biodegradable PLA can be used to create the exact custom-made scaffold depending on the user needs (i.e. shape of a bone fracture), whereas the bioactive material (bioglass® 45S5) assists bone regeneration by HAp development. On the other hand, biocompatible red emissive boron-doped carbon dots could allow for monitoring of the procedure. Scaffolds were tested for their in vitro bioactivity by soaking in simulated body fluid (SBF) solution. In addition, in vitro cytotoxicity testing confirmed the low toxicity of the composite materials used for creating the scaffolds. Degradation of the PLA scaffold initiated immediately providing space for bone regeneration. HAp development was confirmed by scanning electron microscopy - energy dispersive X-ray spectroscopy (SEM/EDS) and infrared spectroscopy (IR). Ultraviolet visible and photoluminescence spectroscopies were used to evaluate the properties of the carbon dots as well as composite materials. Results indicate that this is a promising technique for confronting asymmetric or irregular-shaped bone fractures with simultaneous monitoring of the healing process through bioimaging.