A Multispectral Photoacoustic Tracking Strategy for Monitoring of Macrophages in Inflammation

Inflammation is a common defensive response of vascular system that involves the activation and mediation of immune cells and stem cells homing. However, it is usually hard to track and analyze the real-time status of these cell types toward inflammation microenvironment in a large field of view with desired resolution. Here, we designed and synthesized near-infrared absorbing semiconducting polymer nanoparticles, BBT-TQP-NP (BTNPs), as the cell tracker, and utilize their photoacoustic activity to unveil the targeting behaviors of macrophages, neutrophils, and mesenchymal stem cells to the inflamed sites in mice. Facilitated by a multispectral optical-resolution photoacoustic microscopy (ORPAM), we can continuously monitor the in vivo photoacoustic signals of the labeled cells with cellular resolution in a wide-field (a circle field-of-view with a diameter of 9 mm). In addition, the highly sensitive observation of vascular microstructures and labeled cells can reveal the time-dependent accumulating behaviors of various cell types towards inflammation sites. As a result, our study offers an effective and promising tracking strategy to analyze the in vivo status and fate of functional cells in targeting the diseased/damaged regions.

Source：Zeshun Li, Tingting Li, Chen Zhang, Jenshyang Ni, Yaoyao Ji, Aihui Sun, Dinglu Peng, Weijun Wu, Lei Xi, Kai Li, A multispectral Photoacoustic Tracking Strategy for Wide-field and Real-time Monitoring of Macrophages in Inflammation, Analytical Chemistry, 93(24): 8467-8475, 2021.