Near-Infrared Light-Responsive Hydrogel for Specific Recognition and Photothermal Site-Release of Circulating Tumor Cells

Isolation of single circulating tumor cells (CTCs) from patients is a very challenging technique that may promote the process of individualized antitumor therapies. However, there exist few systems capable of highly efficient capture and release of single CTCs with high viability for downstream analysis and culture. Herein, we designed a near-infrared (NIR) light-responsive substrate for highly efficient immunocapture and biocompatible site-release of CTCs by a combination of the photothermal effect of gold nanorods (GNRs) and a thermoresponsive hydrogel. The substrate was fabricated by imprinting target cancer cells on a GNR-pre-embedded gelatin hydrogel. Micro/nanostructures generated by cell imprinting produce artificial receptors for cancer cells to improve capture efficiency. Temperature-responsive gelatin dissolves rapidly at 37 °C; this allows bulk recovery of captured CTCs at physiological temperature or site-specific release of single CTCs by NIR-mediated photothermal activation of embedded GNRs. Furthermore, the system has been applied to capture, individually release, and genetically analyze CTCs from the whole blood of cancer patients. The multifunctional NIR-responsive platform demonstrates excellent performance in capture and site-release of CTCs with high viability, which provides a robust and versatile means toward individualized antitumor therapies and also shows promising potential for dynamically manipulating cell–substrate interactions in vitro.