Clinicians today have an arsenal of more than 200 drugs at their disposal for treating a range of cancers—68 drugs were approved between 2011 and 2016 alone. But many chemotherapeutic agents pose stubborn challenges: they cause serious side effects because they kill healthy cells in addition to cancer cells; some forms of cancer develop resistance to drugs; and many such chemotherapies, being poorly water-soluble, demonstrate low bio-availability resulting in sub-optimal drug delivery to cancer cells.