Microalgae Cultivation (Chlorella vulgaris) within Nanocellulose-based Biomaterial Ink for 3D Bioprinting

Abstract

Advances in microtechnology have progressively improved cultivation methods, providing significant benefit through hydrogel immobilization, which enables more controlled nutrient delivery and a conducive environment.  In this work, Chlorella vulgaris, a microalgal species, was used to investigate the cell cultivation and optimal growth conditions within cellulose-based bioinks composed of cellulose nanofibrils (CNF) and carboxymethyl cellulose (CMC). C. vulgaris immobilization serves as a bioprinted living cell model focused on a plant-based system, enhancing the understanding of a modern and simplified cultivation techniques. The growth rates of C. vulgaris cells in CNF/CMC hydrogels were evaluated using colorimetric analysis with different cell cultivation techniques. The morphological structure was analyzed within the CNF/CMC hydrogel, C. vulgaris culture, and the immobilized C. vulgaris in the hydrogel. The optimal conditions at room temperature for C. vulgaris growth were established by preparing the hydrogels with varying CNF and CMC concentration ratios for subsequent 3D bioprinting processes. Remarkably, the 3D-bioprinted hydrogel with a concentration ratio of 5 wt% CNF and 5 wt% CMC demonstrated superior structural integrity, with capability for 3D printing and exceptional C. vulgaris cell growth rates. A green and comprehensive method of nanocellulose-based bioinks showed great properties for the application of other cells’ culture with 3D bioprinting.