Lemon grass derived porous carbon nanospheres functionalized for controlled and targeted drug delivery

Since controlled delivery of drug molecules to targeted sites are essential criteria for effective drug delivery, herein a porous nanocarrier chemically functionalized with the drug molecules is developed to accomplish this goal. ∼150 nm diameter porous carbon nanospheres were produced on a large scale from abundant lemon grass (Cymbopogon flexuosus) via silica etching and ball milling followed by subsequent functionalization steps to chemically bind the drugs (anticancer doxorubicin, DOX and cell impermeant propidium iodide, PI). A large quantity of drug could be loaded because of high surface area through chemical functionalization, π-π stacking and hydrophobic interactions both inside the pores and at the nanosphere surface as compared to simple physisorption. The pH and time dependent drug release occurs inside cancer (HeLa) cells whereas normal cells (HEK-293) remain almost unaffected. The internalization of porous nanocarriers could even successfully deliver PI inside the HeLa cells whereas the performance of non-porous carbon nanospheres was extremely poor with DOX. The requirements of a cost-effective and pH responsive nanocarrier with decent porosity and ability to covalently functionalize the drug are found to be crucial for its controlled delivery to specific cells and to retain the viability of normal cells.