Bacterial Nanocellulose and Titania Hybrids: Cytocompatible and Cryopreservable Cell Carriers

Carrier-assisted cell transplantation offers new strategies to improve the clinical outcomes of cellular therapies. Bacterial nanocellulose (BC) is an emerging biopolymer that might be of great value in the development of animal-free, customizable, and temperature-stable novel cell carriers. Moreover, BC exhibits a myriad of modification possibilities to incorporate additional functionalities. Here, we have synthesized BC-titanium dioxide (TiO₂) nanocomposites (BC/TiO₂) to evaluate and compare the suitability of not only BC but also a model hybrid nanobiomaterial as cell transplantation supports. This work provides thorough information on the interactions between BC-based substrates and model human cells in terms of cell attachment, morphology, proliferation rate, and metabolic activity. Two methods to partially retrieve the adhered cells are also reported. Both BC and BC/TiO₂ substrates are positively evaluated in terms of cytocompatibility and endotoxin content without detecting major differences between BC and BC nanocomposites. Lastly, the effective cryopreservation of cells-BC and cells-BC/TiO₂ constructs, yielding high cell viability and intact cell carrier's characteristics after thawing, is demonstrated. Taken together, our results show that both BC and BC/TiO₂ enable to integrate the processes of expansion and long-term storage of human cells in transportable, robust and easy to manipulate supports.