Local release and isolation of circulating tumor cells captured by the nano-morphologic substrate coated with gelatin under near-infrared light

The detection and isolation of circulating tumor cells (CTCs) from blood samples are very important for the diagnosis and analysis of tumors. Therefore, it is urgent to develop an efficient method to capture and isolate cells, especially to further isolate rare cells from the separated cells. In this work, we fabricated a near infrared (NIR) light-responsive TiO2 nanopillar arrays (TNA) substrate for efficient capture and release of CTCs. The substrate was coated with a gelatin (GEL) film doped with gold nanorods (GNR). Due to the introduction of nanopatterned surface, CTCs can be captured efficiently by the TNA substrate. Furthermore, due to the temperature-sensitive property of gelatin and the photothermal effect of GNR, the captured cells can be released under NIR irradiation. More importantly, the selected cells can be released by adjusting the size and location of NIR light. In addition, due to the good biocompatibility of gelatin and the low phototoxicity of NIR, the cells released by this method are highly viable. Our method provides a good strategy for capturing and releasing cells, especially to locally release rare cells while with high cell viabilities.