Polydopamine-enabled surface functionalization of gold nanorods for cancer cell-targeted imaging and photothermal therapy

Aim: A novel biomimetic strategy was employed for presenting antibodies on gold nanorods (NRs) to target growth factor receptors on cancer cells for use in photothermal therapy. Materials & methods: Polydopamine (PD) was polymerized onto gold NRs, and EGF receptor antibodies (anti-EGFR) were immobilized onto the layer. Cell-binding affinity and light-activated cell death of cancer cells incubated with anti-EGFR-PD-NRs were quantified by optical imaging. Results: PD was deposited onto gold NRs, and antibodies were bound to PD-coated NRs. Anti-EGFR-PD-NRs were stable in media, and were specifically bound to EGFR-overexpressing cells. Illumination of cells targeted with anti-EGFR-PD-NRs enhanced cell death compared with nonirradiated controls and cells treated with antibody-free NRs. Conclusion: PD facilitates the surface functionalization of gold NRs with biomolecules, allowing cell targeting and photothermal killing of cancer cells. PD can potentially coat a large variety of nanoparticles with targeting ligands as a strategy for biofunctionalization of diagnostic and therapeutic nanoparticles.