Functionalization of nanocellulose applied with biological molecules for biomedical application: A review

Nanocellulose has great potential in the biomedical field due to its biocompatibility, large specific surface area, and customizable surface chemistry. However, due to the bioinert nature and mismatch of the mechanical strength, nanocellulose itself has no cell adhesion ability and cannot directly promote cell growth and reproduction. Recently, surface functionalization of nanocellulose has been reported as an indispensable strategy for improving its bioactivities or other physic-chemical properties. In this paper, functionalization strategies of nanocellulose based on its inherent hydroxyl, aldehyde, carboxyl, and sulfate group reactions are reviewed. Biomacromolecules, such as peptides, proteins, and DNA that are commonly used in functionalization for different biomedical applications are summarized. Prospects and ongoing challenges of nanocellulose-based biomaterials application, as well as these advanced processing technologies such as additive manufacturing, nanomanufacturing, and bio-manufacturing are also discussed. This review is supposed to serve as a guideline for the development of nanocellulose-based biomaterials in biomedical applications.