Electric field-assisted MnO 2 nanomaterials for rapid capture and in situ delivery of circulating tumour cells.

The heterogeneity of cancer has become a major obstacle to treatment, and the development of an efficient, fast, and accurate drug delivery system is even more urgent. In this work, we designed a device that integrated multiple functions of cell capture, in situ manipulation, and non-destructive release on a single device. With an applied electric field, an intelligent device based on MnO 2 nanomaterials was used to realize efficient and rapid capture of cancer cells in both patients' blood and artificial blood samples. This device could capture cancer cells with high efficiency (up to about 93%) and strong specificity in blood samples, the capture time was nearly 50 min faster than that of natural sedimentation, and reduce the effects on cells caused by long-time in vitro culture. In addition, Mn 3+ on the surface of the MnO 2 substrate was reduced to Mn 2+ by an electrochemical method, partial dissolution occurred, and then the captured cells were non-destructively released with rapid speed (about 8 s) and high efficiency (about 94 ± 2%). For in situ regulation, upon applying a pulse electric field, the captured cells were perforated nondestructively, and extracellular molecules could be delivered to the captured cells with well-performed dose and temporal controls. As a proof-of-concept application, we proved that the device could capture circulating tumor cells in peripheral blood faster and achieve in situ drug delivery. Finally, it can also quickly release circulating tumour cells for subsequent analysis, highlighting its accuracy, due to which it is widely used in medical treatment, basic tumor research and drug development.