Colloidal Porous AuAg Alloyed Nanoparticles for Enhanced Photo acoustic Imaging.
Colloidal porous AuAg alloyed nanoparticles (pAuAgNPs) were synthesized by galvanic replacement reaction from Ag nanocubes. pAuAgNPs have 50 nm exterior diameter and half of their inner space consists of voids that have a bimodal size distribution with peaks at 21 nm and 8.3 nm. pAuAgNPs showed a plasmonic peak at 750 nm, which was exploited for photoacoustic (PA) imaging. Gold nanorods (AuNRs) were prepared and used as the control; they have a strong plasmonic peak at 720 nm. In in vitro experiments at respective plasmonic peak excitations, pAuAgNPs gave stronger PA signals than AuNRs by 8.9 times per particle, and 11.7 times per dosage by exogenous atom. The high surface area per volume as a result of the inner voids amplified the PA signals by efficient thermo acoustic conversion. In experiments of chicken tissue phantoms, pAuAgNPs showed PA signals through 4.5 cm thick tissue, whereas AuNRs gave no detectable signal. In whole body in vivo experiments, pAuAgNPs injected into the body showed 2.7 times stronger PA signals than did AuNRs. Coating the pAuAgNPs with a silica layer additionally increased their PA signal by 1.8 times when compared to the uncoated.
ACS applied materials interfaces