A preliminary study of photoacoustic/ultrasound dual-mode imaging in melanoma using MAGE-targeted gold nanoparticles

Nanoprobes are small enough to circulate within the vasculature and can reach tumour tissues through the endothelial gap, providing a new strategy for accurate tumour monitoring and imaging-guided antitumour therapy at the molecular level. Both photoacoustic and ultrasonic imaging are noninvasive tools for cancer detection via the application of nanoprobes. In this study, a polymeric multifunctional nanoparticle probe loaded with gold nanorods (Au-NRs) and liquid perfluorocarbon (perfluorinated hexane/PFH) and conjugated to a monoclonal antibody (MAGE-1 antibody) to melanoma-associated antigens (MAGE) targeting melanoma was successfully prepared by the double emulsion and carbodiimide methods as a targeted photoacoustic/ultrasound dual-mode imaging contrast agent (MAGE-Au-PFH-NPs). Cell-targeting experiments in vitro showed large amounts of MAGE-Au-PFH-NPs surrounding B16 melanoma cells in the targeted group. The photoacoustic signal in the targeted group was significantly increased, and the duration was longer than that in the untargeted group in vivo. The photoacoustic signal of the nanoprobes was enhanced with increased Au-NR concentration in the photoacoustic experiment in vitro. The enhanced signal was observed by ultrasound after 808-nm laser irradiation. A cytotoxicity and biocompatibility test showed that MAGE-Au-PFH-NPs exhibited good biological safety. The MAGE-Au-PFH-NPs can be used as a photoacoustic/ultrasound dual-mode contrast agent to lay the foundation for a promising new approach for the noninvasive targeting, monitoring and treatment of tumours.