The present study aimed to encapsulate rivastigmine (a drug used for treatment of the Alzheimer disease) in poly (methyl methacrylate – co – acrylic acid), P(MMA-co-AA), nanoparticles functionalized with the transcription activator peptide (TAT) for biomedical applications. Encapsulation was performed in situ through miniemulsion polymerization at different preparation conditions and the highest encapsulation efficiencies (around 80%) were obtained when the comonomer mixture contained 7.5 wt% of acrylic acid in methyl methacrylate. Afterwards, functionalization trials of the previously prepared polymer nanoparticles were performed through chemical adsorption, leading to high TAT immobilization efficiencies (94%). Additionally, toxicity bioassays conducted with Caco-2 cells monolayers revealed that the cytotoxicity of obtained particles was low and did not depend on the nanoparticle composition. Besides, the obtained results indicated that the functionalized nanoparticles could cross the intestinal epithelial barrier successfully. Finally, the obtained particles presented good stability, could be prepared with high encapsulation and functionalization efficiencies, and presented advantageous biological properties that encourage the future development of biomedical uses.