The work presents a full physicochemical characterization of sulfonated cellulose beads prepared from Cladophora nanocellulose intended for use in biological systems. 2,3-Dialdehyde cellulose (DAC) beads were sulfonated, and transformation of up to 50% of the aldehyde groups was achieved, resulting in highly charged and porous materials compared to the compact surface of the DAC beads. The porosity could be tailored by adjusting the degree of sulfonation, and a subsequent reduction of the aldehyde groups to hydroxyl groups maintained the bead structure without considerable alteration of the surface properties. The thermal stability of the DAC beads was significantly increased with the sulfonation and reduction reactions. Raman spectroscopy also showed to be a useful technique for the characterization of sulfonated cellulose materials.