In situ Analysis of the Fate and Behavior of Inorganic Nanomaterials in Biological Systems by Synchrotron Radiation X-ray Probe Techniques

Background: The comprehensive understanding of nanomaterials’ behavior in biological systems is essential in accurately modeling and predicting nanomaterials’ fate and toxicity. Synchrotron radiation (SR) X-ray techniques, based on their ability to study electronic configuration, coordination geometry, or oxidative state of nanomaterials with high sensitivity and spatial resolution, have been introduced to analyze the transformation behavior of nanomaterials in biological systems. Methods: Previous researches in this field are classified and summarized. Results: To start with, a brief introduction of a few widely used SR-based analytical techniques including X-ray absorption spectroscopy, X-ray fluorescence microprobe, scanning transmission Xray microscopy and circular dichroism spectroscopy is provided. Then, the recent advances of their applications in the analysis of nanomaterial behaviors are elaborated based on different nanomaterial transformation forms such as biodistribution, biomolecule interaction, decomposition, redox reaction, and recrystallization/agglomeration. Finally, a few challenges faced in this field are proposed. Conclusion: This review summarizes the application of SR X-ray techniques in analyzing the fate of inorganic nanomaterials in biological systems. We hope it can help the readers to have a general understanding of the applications of SR-based techniques in studying nanomaterial biotransformation and to stimulate more insightful research in relevant fields.