The invention generally refers to a cell-targeting nanoparticle, wherein the cell-targeting nanoparticle is directly conjugated to at least one cysteine-containing peptide, wherein the cysteine-containing peptide is selected from the group consisting of glutathione (GSM, a GSH-containing peptide, and a peptide comprising a nuclear localization signal (NLS) sequence and a transporter sequence, and methods of using the cell-targeting nanoparticle.