Three dimensional (3D) bioplotting requires appropriate crosslinkers to crosslink the hydrogel precursor while simultaneously maintaining the viability of embedded cells. However, the evaluation and comparison of various types of crosslinkers in bioplotting remains underexplored to date. This paper presents our study of the influence of three ionic crosslinkers-calcium chloride (CaCl2), barium chloride (BaCl2), and zinc chloride (ZnCl2)-on the mechanical and biological properties of 3D bioplotted alginate scaffolds. The scaffold mechanical properties characterized included the elastic modulus, swelling, and degradation while the biological properties considered included Schwann cell viability and surface morphology. The mechanical and biological properties of the bioplotted scaffolds were both dependent on the crosslinkers used for fabrication; specifically, crosslinking ions resulted in the elastic modulus of the hydrogels decreasing in the order BaCl2>CaCl2>ZnCl2 over 42 days while Schwann cell viability decreased in the order CaCl2>BaCl2>ZnCl2 over 7 days. Taken together, these results offer insights that are effective in terms of manipulating the 3D bioplotting process so as to tune and optimize the mechanical and biological performance of the plotted scaffolds for tissue engineering applications.
Keywords: 3D: three dimensional; : phosphate ions; Ba2+: barium ion; BaCl2: barium chloride; CAD: computer aided design; CO2: carbon dioxide; COOH−: carboxyl group; Ca2+: calcium ion; CaCl2; CaCl2: calcium chloride; Crosslinker; DMEM: Dulbecco’s modified eagle medium; EDTA: ethylene diamine tetra acetic acid; FBS: fetal bovine serum; HUVEC: human umbilical vein endothelial cells; MW: molecular weight; Mg2+: magnesium ions; Na+: sodium ions; PBS: phosphate buffered saline; PEI: polyethyleneimine; PI: propidium iodide; PRSC: primary rat Schwann cells; RP: rapid prototyping; SEM: scanning electron microscopy; VEGF: vascular endothelial growth factor; Zn2+: zinc ion; ZnCl2: zinc chloride; alginate; cell viability; degradation; elastic modulus; swelling; tissue engineering.