Near-infrared PbS quantum dots functionalized with affibodies and ZnPP for targeted imaging and therapeutic applications

Abstract We report a new theranostic device based on lead sulfide quantum dots (PbS QDs) with optical emission in the near infrared wavelength range decorated affibodies (small 6.5 kDa protein-based antibody replacements) specific to cancer biomarker human epidermal growth factor receptor 2 (HER2), and zinc(II) protoporphyrin IX (ZnPP) combine imaging, targeting therapy within one nanostructure. Colloidal PbS QDs were synthesized aqueous solution nanocrystal diameter of ∼5 nm photoluminescence range. The Z HER2:432 affibody, mutated through introduction two cysteine residues at C-terminus (Afb2C), was used as capping ligand form Afb2C-PbS that have high binding affinity for HER2, which is overexpressed several types including breast cancer. further modified by conjugation ZnPP, acts an anticancer agent. biological activity these tested against SKBR3 (HER2-positive) MDA-MB-231 (HER2-normal) cells, results showing ZnPP-Afb2C-functionalized successfully targeted HER2-overexpressing cells induced cell apoptosis thanks ZnPP. These expand use QD nanoplatform formulation novel nanomaterials delivery combined imaging via direct surface-protein interaction.