Dark-field image of silver nanoparticles with cytotoxic drug monomethyl auristatin E and RPARPAR peptide (RPARPAR-MMAE-AgNP) internalized by PPC-1 prostate cancer cells after 1 h incubation. Extracellular fraction of AgNPs was removed by etching. Scale bar: 20 μm; dotted lines outline cells. Author: Allan Tobi MSc.