Photoacoustic imaging of tumor-targeted HSA-modified S-WS₂ nanosheet probes

As a non-wound, non-invasive, and non-ionizing imaging modality, photoacoustic (PA) imaging, which merges the large penreveretration depth of ultrasound imaging and high contrast of optical imaging, significantly improves the resolution and contrast of biological tissue imaging. Recently, many types of PA probe had been applied to enhance the effect and quality of imaging. Here, we developed single-layer WS₂ (S-WS₂) nanosheets modified by human serum albumin (HSA) as a novel PA agent. The S-WS₂ nanosheets were prepared by protein-assisted exfoliation and exhibit excellent stability and compatibility in physiological environments. In vitro, there is no observable toxicity to cells at the tested concentrations. The S-WS₂ nanosheets not only show significant PA effect due to its high NIR optical absorption but also have great stability for PA signal compared with dye ICG. In vivo, the S-WS₂ nanosheets exhibit efficient tumor retention and outstanding PA contrast performance.