HER-2 antibody conjugated gold nano rod particles for in vivo photothermal therapy

Recent studies reported gold nano rod (AuNRs) exhibit surface plasmonic resonance frequency (SPR) proportional to their aspect ratio. The interaction of AuNRs with electromagnetic radiation corresponding to their SPR could generate local regional heat. With precise control of the aspect ratio, AuNR could interact with near-infrared (NIR) laser light in the biological optical window that best penetrate human tissues to optimize hyperthermia therapy ^[1]. We exploit AuNRs to conjugate HER-2 antibodies specific for targeting tumor cells. HER-2 was reported to be associated with disease prognosis and clinical theray ^[2] and was reported to be over-expressed in many types of cancer. In this study, AuNRs was found to present high bio-compatibility and hemo-compatibility. In vitro laser induced hyperthermia study revealed a selective damage of OECM-1 cancer cells targeted by the AuNR probe. We discovered only the use of AuNR combined correct laser wavelength corresponding to SPR of the AuNR could induce effective hyperthermia therapy. In vivo model using tumor bearing SCID mice, an increase in tumor local temperature and improved therapeutic results were discovered in the AuNRs-HER2 treatment group compared to that of AuNRs alone. In conclusion, HER-2 antibodies conjugated AuNR combined NIR laser could be a potent modality in cancer targeting therapy that could minimize side effects attribute to the nanoscale precision of high temperature delivery. Besides, AuNRs showed a tunable SPR within NIR range could be applied for multiplex photo-thermal effect and combined multiple target photo-acoustic molecular imaging for combined diagnosis and therapy in a single platform.