Abstract
Introduction
Ink engineering can advance 3D-printability for better therapeutics, with optimized proprieties. Herein, we describe a methodology for yielding 3D-printable nanocomposite inks (NC) using low-viscous matrices, via the interaction between the organic and inorganic phases by chemical coupling.
Method
Natural photocurable matrices were synthesized: a protein – bovine serum albumin methacrylate (BSAMA), and a polysaccharide – hyaluronic acid methacrylate (HAMA). Bioglass nanoparticles (BGNP) were synthesized and functionalized via aminosilane chemistry. The functionalization of BSAMA, HAMA, and BGNP were quantified via NMR. To arise extrudable inks, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-Hydroxysuccinimide (NHS) chemistry was used to link innate carboxylic groups of BSAMA/HAMA and amine-functionalized BGNP. Different crosslinker and BGNP amounts were tested. Visible light photopolymerization is performed, using lithium phenyl-2,4,6-trimethylbenzoylphosphinate. The NC's rheological, mechanical, and biological behavior was evaluated before 3D extrusion printability.
Result
All composite formulations effectively immobilized and homogeneously dispersed the BGNP, turning low-viscous materials (< 1 Pa) into shear-thinning formulations with tunable increased elastic/viscous moduli (50-500 Pa). More pronounced increments were found with increasing EDC/NHS and BGNP concentrations. The resulting inks produce robust and stable scaffolds successfully retrieved after post-print photocrosslinking (1-5 kPa). Bioactivity in simulated body fluid and in vitro assays using adipose-derive stem cells revealed a similar calcium/phosphate ratio to that of hydroxyapatite, and increased viability and metabolic activity. BSAMA and HAMA demonstrated distinct natures not only in printability but also in overall cellular performance and mechanical properties, making these ideal for interfacial tissue engineering.
Conclusion
This strategy demonstrated being effective and reproducible to advance nanocomposites for 3D printing using different types of biomaterials. Further, we envision using both inks to produce hierarchical constructs via extrusion printing, better mimicking bone-to-cartilage interfaces.
Acknowledgements
FCT grants (DOI:10.54499/2022.04605.CEECIND/CP1720/CT0021), (BI/UI89/10303/2022), (PRT/BD/154735/2023); EU's Horizon 2020 research and innovation programs InterLynk (Nº953169) and SUPRALIFE (Nº101079482) projects; CICECO-Aveiro Institute of Materials projects (DOI:10.54499/UIDB/50011/2020), (DOI:10.54499/UIDP/50011/2020), and (DOI:10.54499/LA/P/0006/2020), financed by FCT/MCTES(PIDDAC).
