“…The IC50 value found for functionalised chitosan was around 1 mg/mL after 72 h of exposure, while cell viability was over 80% for the higher tested concentration (2 mg/mL) of bare chitosan nanoparticles. Other researchers have also observed increased cytotoxic behaviour of silica materials after different surface chemical treatments (Santos et al, 2010) or by anchoring functional groups, such as amine molecules (Bhattacharjee et al, 2010;Puerari et al, 2019;Ruizendaal et al, 2009;Vicentini et al, 2017) or carboxylic acid groups (Petushkov et al, 2009).…”