▎ 摘　　要

Two-photon microscopy is an important technology for both ex vivo tissue and in vivo animal imaging, due to its deep-penetration and optical sectioning capability in biological tissue. Graphene has consistently been a hot research topic owing to its unique optical, electronic and mechanical properties. In this paper, we synthesized graphene oxide nanoparticles (GONs), which is a derivative of graphene, and characterized its nonlinear optical properties. GONs were microinjected into the embryos of zebrafish, and no in vivo toxicity towards zebrafish could be observed according to a series of biological testings. We then applied GONs in two-photon microscopy for bioimaging of zebrafish. The GONs treated zebrafish was imaged at different growth stages, with a scanning microscope equipped with a 720 nm-femtosecond laser. GONs generated strong two-photon fluorescence signals inside zebrafish, which could help characterizing the morphologies of zebrafish vividly.