Zinc oxide nanorods constitute a promising material for making the transducer elements of biosensor systems because of their physical and chemical properties. We report here studies of the effects of annealing temperature on the concentration of the surface hydroxyl groups ensuring successful immobilization of biologically recognizable elements was assessed. X‑ray photoelectron spectroscopy results showed that annealing at 500 °C increased the concentration of oxygen vacancies compared with annealing at 300 °C. FTIR spectroscopy data also confirmed a higher concentration of OH groups in the sample annealed at 500 °C than in commercial nanoparticles.