Nanocellulose is served as a promising material in biomedical and pharmaceutical areas since its inherent biocompatibility, biodegradability and tailorable surface chemistry. Moreover, the highly hydrated three-dimensional network structure makes the research of nanocellulose hydrogel a hotspot because it can simulate the extracellular matrix of human organ tissues very well. Up to now, the research teams from various countries made biological scaffold structure of human auricle structure, nose and meniscus structure successfully by combining nanocellulose hydrogel and alginate, hyaluronic acid, chitosan and other biomacromolecules. The studies of in vivo transplantation and in vitro cell culture have found that bio-scaffold structure based on nanocellulose can well support the growth, reproduction, differentiation and other cell functions of animal cells, which has a good prospect for biomedical applications. However, the current research on nanocellulose hydrogel tissue engineering materials still faces many problems. On the one hand, nanocellulose is biologically inert, it has no cell adhesion ability and cannot promote cell growth and reproduction directly, resulting in slow down cell proliferation. On the other hand, even though nanocellulose can be crosslinked by some metal ions, the mechanical strength of nanocellulose hydrogel products for tissue engineering is still extremely low so that makes it is difficult to simulate and maintain the extracellular matrix to provide the necessary mechanical support and guidance for cells. Recently, it has been found that the cell growth ability and mechanical properties of nanocellulose hydrogel can be improved through biofunctionalization or surface modification. This brief review summarized some traditional functionalization approaches of nanocellulose such as hydroxyl reactions, aldehyde reactions, Carboxyl reactions and sulfate reactions. Furthermore, the bioconjugation methods between biological molecules and nanocellulose hydrogel which based on traditional functionalization approaches have been offered. Not only that, the potential applications, future outlook, and ongoing challenges associated with the biofunctionalization of nanocellulose with biomolecules are discussed. In particular, we emphasize the critical roles of nanocellulose surface chemistry and micro/macro-structure in biofunctionalization as well as in applications.

nanocellulose,Tissue engineering,Biofunctionalization,Extracellular matrix,Hydrogel