Multicolor Photoacoustic Volumetric Imaging of Subcellular Structures

Photoacoustic imaging (PAI) has been widely used inmultiscale and multicontrast imaging of biological structures andfunctions. Optical resolution photoacoustic microscopy (OR-PAM),an emerging submodality of PAI, features high lateral resolution andrich optical contrast, indicating great potential in visualizing cellularand subcellular structures. However, three-dimensional (3D) imagingof subcellular structures using OR-PAM has remained a challenge dueto the limited axial resolution. In this study, we propose a multicolor3D photoacoustic microscopy with high lateral/axial resolutions of0.42/2 and 0.5/2.5 μm at 532 and 780 nm excitation, respectively.Owing to the significantly increased axial resolution, we couldvisualize the volumetric subcellular structures of melanoma cellsusing intrinsic contrast. In addition, we carried out multicolor imaging of labeled microtubules/clathrin-coated pits (CCP)and microtubules/mitochondria, respectively, with one scanning by using two different excitation wavelengths. The internalconnections between different subcellular structures are revealed by quantitatively comparing the spatial distributions ofmicrotubules/CCP and microtubules/mitochondria in a single cell. Current results suggest that the proposed OR-PAM mayserve as an efficient tool for subcellular and cytophysiological studies.

Source: Aihui Sun, Yaoyao Ji, Yaxi Li, Wenhui Xie, Zhihe Liu, Tingting Li, Tian Jin, Weizhi Qi, Kai Li, Changfeng Wu, Lei Xi, Multicolor Photoacoustic Volumetric Imaging of Subcellular Structures, ACS Nano, 16(2), 3231-3238.