The invention relates to a process for preparing nano-composites to be used for manufacturing biodegradable biomedical devices. According to the invention, the process consists of the surface treatment of micro- and nano-cellulose with plasma with the source immersed into a cellulose liquid suspension, for 5…120 min, to result in cellulose micro- and nano-fibers functionalised at the surface, which are further dispersed in water, they are ultra sound-treated by using an ultrasound probe with a power of minimum 500W, for up to 120 min, and concentrated, thereby resulting in the cellulose nano-fibers which are added to a biopolymer solution in a ratio of 0.1/99.9 and 30/70, while stirring, finally resulting in a nano-composite which is then processed as granules or ground matter.