An intravascular needle coated by ZnO nanoflowers for in vivo elimination of circulating tumor cells

Circulating tumor cells (CTCs) are recognized as the main source of tumor recurrence and metastasis. Eliminating the CTCs in peripheral blood provides a new strategy to reduce the probability of recurrence or metastasis. Here, we proposed a concept to eliminate CTCs by inserting a needle in the superficial blood vessel. Using the property of ZnO and the structure of nanoflowers, we designed a medical needle coated with ZnO nanoflowers (ZNFs), which killed about 90% of captured CTCs in vitro and prevented the injecting CTCs from spreading to lung tissue in BABL/c mouse model. Results in vitro and in vivo demonstrated that the CTCs not only were captured and killed, but also detached from the needle surface after dead, enabling the ZNFs needle continually eliminate CTCs. Furthermore, a theoretical model was presented to explain the penetration mechanism of cells by nanostructures, which indicated that nanoflowers structure can puncture CTCs more easily than vertical nanowire structure. The concept of inserting an intravascular needle provides a potential strategy to lower the concentration of CTCs in blood and reduce the probability of tumor recurrence or metastasis.