Folic acid conjugated poly(amidoamine) dendrimer as a smart nanocarriers for tracing, imaging, and treating cancers over-expressing folate receptors

Cancer is a deadly disease with complicated pathology. Present chemotherapy regimen encounters challenges such as cytotoxicity, non-specificity and development of drug-resistance. So, to overcome these challenges, nano carriers come into play. As the name suggests, nano-carriers are nano-sized molecules that encapsulate the drug and carry it specifically to the site of action. PAMAM dendrimer has been extensively studied in the field of cancer therapy. PAMAM dendrimers specifically aim at tumor cells via passive or active targeting strategies and do not affect the surrounding normal cells, reducing non-specific-drug targeting related toxicity. Hydrophobic chemotherapeutic drugs can be easily shielded inside the core of PAMAM dendrimer, increasing their systemic solubility and concentration inside tumor cells. the dendrimer molecule comprises of a central atom or a group of atoms while branches of dendrimer are composed of carbon, that are added sequentially through a series of synthetic reactions, creating a sphere-shaped dendritic structure. This addition of consecutive "generations" of branches regulates the size of the dendrimer. The periphery of PAMAM dendrimer can also be varied using various conjugates to enhance its tumor specificity. Certain cancer cells overexpress folate receptors, so to target it, folic acid conjugated dendrimers are widely under research. In this review, we discussed the action and characterization of various folate-PAMAM dendrimers delivering diagnostic agents, drugs, and genes against different types of tumor cells.