The present subject matter relates to light-activatable polymeric nanoparticles (NPs) for the transportation and release of an active substance, methods for obtain said particles and their uses. A light-activatable nanoparticle for the transportation and release of an active substance, comprising a polycation preferably a polimer polycation, a polyanion and a light-sensitive photochrome attached to the polycation or the polyanion, wherein said photochrome is hydrophobic and suitable to photo-cleave when activated by an irradiation source, generating a negative charge and releasing the active substance. Light-activatable. The disclosure subject matter shows that NPs are a highly efficient drug delivery system to primary leukemic cells based on opto-nanomedicine system. Therefore, the present disclosure is useful for remote control in the release of biomolecules with spatio-temporal resolution with applications in the areas of general therapeutic and regenerative medicine applications.