Abstract Photodynamic therapy (PDT) using TiO 2 nanoparticles has become an important alternative treatment for different types of cancer due to their high photocatalytic activity and high absorption of UV‐A light. To potentiate this treatment, we have coated commercial glass plates with TiO 2 nanoparticles prepared by the sol–gel method (TiO 2 ‐m), which exhibit a remarkable selectivity for the irreversible trapping of cancer cells. The physicochemical properties of the deposited TiO 2 ‐m nanoparticle coatings have been characterized by a number of complementary surface‐analytical techniques and their interaction with leukemia and healthy blood cells were investigated. Scanning electron and atomic force microscopy verify the formation of a compact layer of TiO 2 ‐m nanoparticles. The particles are predominantly in the anatase phase and have hydroxyl‐terminated surfaces as revealed by Raman, X‐ray photoelectron, and infrared spectroscopy, as well as X‐ray diffraction. We find that lymphoblastic leukemia cells adhere to the TiO 2 ‐m coating and undergo amoeboid‐like migration, whereas lymphocytic cells show distinctly weaker interactions with the coating. This evidences the potential of this nanomaterial coating to selectively trap cancer cells and renders it a promising candidate for the development of future prototypes of PDT devices for the treatment of leukemia and other types of cancers with non‐adherent cells.