Photoacoustic (PA) tomography imaging is an emerging, versatile, and noninvasive imaging modality, which combines the advantages of both optical imaging and ultrasound imaging. It opens up opportunities for noninvasive imaging of angiogenesis, a feature of skin pathologies including cancers and psoriasis. In this study, high-density copper oleate encapsulated within a phospholipid surfactant (CuNPs) generated a soft nanoparticle with PA contrast comparable to gold. Within the near-infrared window, the copper nanoparticles can provide a signal more than 7 times higher that of blood. ανβ3-targeted of CuNPs in a Matrigel mouse model demonstrated prominent PA contrast enhancement of the neovasculature compared to mice given nontargeted or competitively inhibited CuNPs. Incorporation of a sn-2 lipase-labile fumagillin prodrug into the CuNPs produced marked antiangiogenesis in the same model, demonstrating the theranostic potential of a PA agent for the first time in vivo. With a PA signal comparable to gold-based nanoparticles yet a lower cost and demonstrated drug delivery potential, ανβ3-targeted CuNPs hold great promise for the management of skin pathologies with neovascular features.
We demonstrated the potential of carbon nanoparticles (CNPs) as exogenous contrast agents for both thermoacoustic
(TA) tomography (TAT) and photoacoustic (PA) tomography (PAT). In comparison to deionized water, the CNPs
provided a four times stronger signal in TAT at 3 GHz. In comparison to blood, The CNPs provided a much stronger
signal in PAT over a broad wavelength range of 450-850 nm. Specifically, the maximum signal enhancement in PAT
was 9.4 times stronger in the near-infrared window of 635-670 nm. In vivo blood-vessel PA imaging was performed
non-invasively on a mouse femoral area. The images, captured after the tail vein injection of CNPs, show a gradual
enhancement of the optical absorption in the vessels by up to 230%. The results indicate that CNPs can be potentially
used as contrast agents for TAT and PAT to monitor the intravascular or extravascular pathways in clinical applications.