The article by Åkerman et al. explores the feasibility of in vivo targeting of semiconductor quantum dots (qdots) using peptide coatings. Qdots are small, luminescent inorganic nanocrystals with unique optical properties, making them potential intravascular probes for diagnostics and drug delivery. The authors coated ZnS-coated CdSe qdots with lung-targeting peptides (GFE), blood vessel-targeting peptides (F3), and lymphatic vessel-targeting peptides (LyP-1). In vitro and in vivo experiments demonstrated that these peptide-coated qdots specifically accumulated in the lungs and tumors, respectively, without nonspecifically accumulating in other organs. Adding polyethylene glycol (PEG) to the qdot coating reduced nonspecific accumulation in the reticuloendothelial system, enhancing the circulation half-life of the nanoparticles. The study highlights the potential of peptide-coated qdots for targeted drug delivery and disease sensing in living organisms.The article by Åkerman et al. explores the feasibility of in vivo targeting of semiconductor quantum dots (qdots) using peptide coatings. Qdots are small, luminescent inorganic nanocrystals with unique optical properties, making them potential intravascular probes for diagnostics and drug delivery. The authors coated ZnS-coated CdSe qdots with lung-targeting peptides (GFE), blood vessel-targeting peptides (F3), and lymphatic vessel-targeting peptides (LyP-1). In vitro and in vivo experiments demonstrated that these peptide-coated qdots specifically accumulated in the lungs and tumors, respectively, without nonspecifically accumulating in other organs. Adding polyethylene glycol (PEG) to the qdot coating reduced nonspecific accumulation in the reticuloendothelial system, enhancing the circulation half-life of the nanoparticles. The study highlights the potential of peptide-coated qdots for targeted drug delivery and disease sensing in living organisms.