Bionanotechnology for drug delivery brings together nanoscale engineering and biology to improve the precision, efficiency, and safety of therapeutic interventions. Nanocarriers such as liposomes, dendrimers, polymeric nanoparticles, and exosomes are being engineered to deliver drugs, genes, and biomolecules directly to diseased cells while minimizing side effects. These systems can be programmed for controlled release, stimuli responsiveness, and targeted accumulation at pathological sites, such as tumors or inflamed tissues. Functionalization with ligands, antibodies, or peptides allows for selective recognition of cell receptors, enhancing uptake and therapeutic effect. Bionanotechnology for Drug Delivery also enables the crossing of biological barriers, including the blood-brain barrier, which is critical for treating neurological disorders. This advanced delivery paradigm is transforming pharmacology by increasing treatment efficacy while reducing systemic toxicity.