Multifunctional BSA-Au nanostars for photoacoustic imaging and X-ray computed tomography

- BSA-AuNSs are applied in dual-modal CT/PA imaging.
- BSA-AuNSs are suitable for imaging application and developing targeted probes.
- We noninvasively track the liver kinetics of nanoparticles by PA tomography.
- We explore the biodistribution of the nanoparticles by PA tomography.

We report the synthesis and characterization of bovine serum albumin-capped Au nanostars (BSA-AuNSs) for dual-modal computed tomography (CT)/photoacoustic (PA) imaging application. The BSA-AuNSs have an average size of 85 nm, and a surface plasmon resonance (SPR) peak at approximately 770 nm. They have excellent biocompatibility, good X-ray attenuation, and great PA contrast enhancement properties. When injected intravenously, liver signal markedly increases in both CT and PA modalities. The in vivo biodistribution studies and pathology results showed that the BSA-AuNSs were mainly excreted through the liver and intestines with no obvious biotoxicity. These results indicate that BSA-AuNSs have high potential to be used as dual-modal CT/PA imaging contrast agents or further used to develop targeted probes. This preliminary study suggests that PA tomography may be used to non-invasively trace the kinetics and biodistribution of the nanoparticles.

The new born PA imaging has attracted much attention owing to their excellent spatial resolution, high sensitivity, and good soft tissue contrast. The dual-modal CT/PA imaging holds great potential in clinic diagnostics. Here we demonstrated that BSA-capped Au nanostars can be employed as CT/PA dual-modality contrast agents for in vivo imaging. Furthermore, the data revealed that these nanoparticles were excreted via liver, which suggested PA imaging as a useful tool to track the kinetics of nanoparticles in liver.131