Biodegradable germanium nanoparticles as contrast agents for near-infrared-II photoacoustic imaging

Pengbo He, Guo Chen, Mengling Huang, Lili Jing, Wen Wu*, Hao Chung Kuo, Chang Ching Tu*, Sung Liang Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Photoacoustic (PA) imaging using contrast agents with strong near-infrared-II (NIR-II, 1000-1700 nm) absorption enables deep penetration into biological tissue. Besides, biocompatibility and biodegradability are essential for clinical translation. Herein, we developed biocompatible and biodegradable germanium nanoparticles (GeNPs) with high photothermal stability as well as strong and broad absorption for NIR-II PA imaging. We first demonstrate the excellent biocompatibility of the GeNPs through experiments, including the zebrafish embryo survival rates, nude mouse body weight curves, and histological images of the major organs. Then, comprehensive PA imaging demonstrations are presented to showcase the versatile imaging capabilities and excellent biodegradability, including in vitro PA imaging which can bypass blood absorption, in vivo dual-wavelength PA imaging which can clearly distinguish the injected GeNPs from the background blood vessels, in vivo and ex vivo PA imaging with deep penetration, in vivo time-lapse PA imaging of a mouse ear for observing biodegradation, ex vivo time-lapse PA imaging of the major organs of a mouse model for observing the biodistribution after intravenous injection, and notably in vivo dual-modality fluorescence and PA imaging of osteosarcoma tumors. The in vivo biodegradation of GeNPs is observed not only in the normal tissue but also in the tumor, making the GeNPs a promising candidate for clinical NIR-II PA imaging applications.

Original languageEnglish
Pages (from-to)11544-11559
Number of pages16
Issue number27
StatePublished - 7 Jun 2023


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