Bioactive Bone Scaffolds Using a Custom-Built ۳D Bioprinter and Glass-Doped Alginate Nanocomposite Bioinks: Fabrication and Chemical Analysis

The development of bioactive, printable scaffolds remains a central challenge in bone tissue engineering, particularly when balancing material cost, printability, and biological performance. This study reports the design and validation of a low‑cost, open‑source extrusion‑based ۳D bioprinter and its application for fabricating glass‑reinforced alginate nanocomposite scaffolds. A Cartesian‑type, single‑syringe bioprinter with three‑axis motion control was constructed using stepper motors, precision drivers, and a microcontroller. Composite bioinks were formulated with ۲% (w/v) sodium alginate, ۳% (w/v) tricalcium phosphate, and ۱۰ wt% micro‑sized glass powder. Rheological characterization at ۲۵ °C revealed a storage modulus (G′) of ۵۲۰–۵۸۰ Pa and a loss modulus (G″) of ۹۰–۱۵۰ Pa (۱ Hz, ۰.۱–۱۰۰% strain), with G′ > G″ across the entire strain range, confirming gel‑like viscoelastic behavior and shear‑thinning suitability for extrusion printing. Lattice‑structured scaffolds were printed layer‑by‑layer and post‑crosslinked with CaCl₂. Following ۲۸ days of immersion in Simulated Body Fluid (SBF) at ۳۷ °C, scanning electron microscopy (SEM) showed extensive cauliflower‑like apatite deposits on scaffold surfaces, indicating biomineralization. Energy‑Dispersive X‑ray Spectroscopy (EDS) demonstrated a substantial increase in the Ca/P atomic ratio from ۱.۲۲ (untreated) to ۱.۸۳ (after SBF), approaching the stoichiometric hydroxyapatite value of ۱.۶۷. The scaffold surfaces remained structurally intact throughout incubation. These results provide direct quantitative evidence of glass‑induced in vitro bioactivity. The integrated bioprinter‑bioink platform offers a reproducible, accessible, and bioactive solution for bone scaffold fabrication. Future work will address mechanical characterization, degradation kinetics, and cellular validation.

کلیدواژه ها:

۳D bioprinting ، Extrusion‑based bioprinter ، Bone Scaffold ، Alginate ، Bioactive glass ، Nanocomposite bioink