Despite significant advancements in modern medicine, effective treatment of complex diseases such as cancer and neurodegenerative disorders is hindered by the inability of conventional therapies to overcome biological barriers, achieve targeted delivery, and minimize off-target effects. Existing drug delivery systems often lack specificity, leading to suboptimal therapeutic outcomes, systemic toxicity, and reduced patient quality of life. There is an urgent need for innovative delivery platforms that can efficiently transport biotherapeutic agents to specific sites of action while addressing challenges such as poor stability, toxicity, and immunogenicity. This gap underscores the critical importance of developing advanced biomaterials, peptide-based strategies, and nanocarrier systems to transform the landscape of targeted therapeutics.