Alginate-gelatin bioink for bioprinting of hela spheroids in alginate-gelatin hexagon shaped scaffolds

Generating a tissue model mimicking the cervix could be useful for studying treatment of precancerous lesions. In this work, bioprinting of hexagon shaped alginate-gelatin scaffolds laden with HeLa spheroids was presented. The three-dimensional (3D) printing system was designed to extrude alginate-gelatin bioink of different viscosities at an extrusion rate of 1–5 mL/min and printing speed from 10 to 50 mm/s. The biophysical properties of the bioink were characterized using dynamic mechanical analysis, viscometer, degradation test, contact angle measurement, Fourier transform infrared spectroscopy (FTIR), live/dead cell stainings and Raman spectroscopy. The bioink formulated with 10% w/v of alginate and 50% w/v of gelatin (ALG10-Gel50) enabled high fidelity printing for the construction of a multilayered 3D structure. The viscosity of the bioink within 12 Pa s and viscoelasticity of the polymerized bioink (G′ = 0.074 MPa > G″ = 0.028 MPa) exhibited mechanical properties close to the in-vivo system. The scaffolds degraded 35% on the day 16 of culture. The polymerized bioinks exhibited hydrophilicity and contained amino groups as characterized by contact angles and FTIR measurements, respectively. In addition, the 3D microtissues laden in the scaffold were indicated with high cell viability at 95.25 ± 1.75% based on the live/dead cell stainings. The printed microtissues were characterized with the presence of deoxyribonucleic acid, lipids and amino acids associated with the collagen. This paper demonstrated the success in the bioprinting of multilayer hexagon shaped tissue model which is potentially useful for development of an in-vitro cervical cancer model.