Preparation of porous composite bio-carriers from lignin-carbohydrate complexes and cellulose nanocrystals, and their application in the culture of human hepatocytes

Lignin-carbohydrate complexes (LCC) were isolated from poplar wood after ball-milling for 48 h and 72 h. The water-insoluble LCC-48 and LCC-72 were fractionated. Porous spherical composite bio-carriers were prepared by liquid-nitrogen freezing using the water-insoluble LCCs and cellulose nanocrystals (CNC). Fourier transform infrared spectroscopy (FT-IR) showed that the bio-carriers were composed of lignin moieties and polysaccharide units. Scanning electron microscopy (SEM) revealed that the outer surface and cut surface of the spherical carrier had many pores. The specific surface areas of the LCC-72/CNC and the LCC-48/CNC composite carriers were 24.2 m2/g and 28.9 m2/g, respectively, while their pore sizes were 28.6 nm and 33.6 nm, respectively. Both carrier samples had good stability at pH 4.6 to 9.5 for about 50 days. Human hepatocytes were cultured in vitro with the bio-carriers and the cells grew well. A large number of cells adhered to the porous bio-carriers, and the cells of the experimental group to which the carriers were added exhibited higher metabolic activities. The CNC improved the biocompatibility for human hepatocytes. In summary, spherical bio-carriers prepared from LCC/CNC composite displayed high biocompatibility and have potential applications in liver tissue engineering.