Nanocellulose refers to various nanostructured forms of cellulose, including cellulose nanocrystals (CNC), cellulose nanofibres (CNF), and bacterial nanocellulose. These materials have distinctive properties that make them suitable for a wide range of applications. CNF and CNC are well-known for their nanostructured nature and potential in various fields. Bacterial nanocellulose, which is produced by bacteria, stands out due to its high purity, ultrafine network structure, and impressive mechanical properties, making it ideal for biocompatible applications. The mechanisms for using nanocellulose in tissue engineering and bioremediation are still being explored. Cryo-grinding is a promising method for preserving the crystalline structure of nanocellulose and minimising damage during production. This chapter provides an overview of nanocellulose, highlighting its unique properties, production methods, and potential applications in various industries, with an emphasis on its significance in advanced materials and biotechnology.