The present invention comprises a process for preparing water-dispersible single-chain polymeric nanoparticles, which comprises cross-linking a polymer having a solubility equal to or higher than 100 mg per litre of water, and an amount of complementary reactive groups comprised from 5 to 60 molar % of the total amount of monomer units present in the polymer chain； with a crosslinking agent having crosslinkable groups； at a temperature comprised from 20 to 25°C in the absence of a catalyst； to obtain water-dispersible conjugates and compositions containing the nanoparticle； and the use thereof.
