Controlled production of soft magnetic hydrogel beads by biosynthesis of bacterial cellulose

Abstract

It describes a simple process to create soft spherical ferrogels by the biosynthesis of bacterial cellulose (BC). Gluconacetobacter xylinus forms the enclosed structure of the ferrogel, which is a hydrogel containing magnetic nanoparticles (MNPs). The core ferrogel is prepared by incorporating MNPs with cellulose nanofibers (CNFs) in culture medium and a BC shell is produced by the bacteria that moves to the medium surface. Spherical BC ferrogels (SBCFs) are fabricated by dropping the core ferrogel with bacteria on a glass surface coated with poly(tetrafluoroethylene) microbeads followed by culture for seven days. The size of the SBCFs is controlled by the external magnetic force, CNF, and MNP concentrations. The CNF immobilizes MNPs and supports the spherical structure by filling the SBCF structure. Because a highly dense BC layer is formed at the surface of the medium droplets, a unique core–shell structure of SBCF is formed.