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. Author manuscript; available in PMC: 2026 Apr 8.
Published in final edited form as: Biomater Sci. 2025 Apr 8;13(8):1939–1959. doi: 10.1039/d4bm01677g

Fig. 6.

Fig. 6

PA imaging for in vivo immune cell tracking. (A) Schematic depiction of PA imaging system. (B) Absorption spectra of endogenous contrasts in the body. (C) Absorption spectra of common exogenous contrasts128 Copyright © 2021 The Authors. Trends in Biotechnology published by Elsevier. (D) In vitro PA images of tissue mimicking dome phantoms with varying concentrations of gold nanorod labeled cells. Higher concentration of nanorod-labeled cells corresponds with a higher PA signal intensity.83 © 2013 Optical Society of America (E) In vivo PA images of gold nanorods (AuNR@SiO2) and nanorod labeled CIK cells (NP-CIK) delivered via peritumoral injection. Signal was detected up to day 4, demonstrating the use of PA imaging for longitudinal noninvasive, in vivo tracking of immune cells.85 © Yang et al. 2016.