A nanocomplex containing a delivery agent and a pharmaceutical agent. The nanocomplex has a particle size of 50 to 1000 nm, the delivery agent binds to the pharmaceutical agent via non-covalent interaction or covalent bonding, and the pharmaceutical agent is a modified peptide or protein formed of a peptide or protein and an added chemical moiety that contains an anionic group, a disulfide group, a hydrophobic group, a pH responsive group, a light responsive group, a reactive oxygen species responsive group, or a combination thereof.