Figure 19.

Chain‐like gold nanoparticle (CGNP) clusters for multimodal photoacoustic microscopy (PAM) and OCT enhanced molecular imaging. Experimental setup of PAM and OCT equipment. a) Schematic illustration of the imaging system. b) Physical setup. In PAM mode, nanosecond excitation laser (450–710 nm) delivered and focused onto the retina. To enable multimodal imaging, the excitation laser beam utilized to induce photoacoustic signal was coaxially aligned with OCT multispectral luminescence with a center wavelength at 805 and 905 nm. The generated acoustic signal was detected by a needle‐shaped hydrophone ultrasonic transducer, and the recorded data was used to reconstruct PAM images. A spectrometer was used to detect the reflected OCT light interfered with the reference light and the interference intensity spectra. Retina was scanned by a galvanometer. c) Illustration of in vivo multimodal imaging after intravenous injection of CGNP clusters‐RGD into the rabbit model. Photoacoustic signals from rabbit retina was produced using nanosecond pulsed laser illumination at 578 or 650 nm. Reproduced under the terms of the CC‐BY 4.0 license.^{[ 132 ]} Copyright 2020, The Authors. Published by Nature Publishing Group.