Abstract: The present disclosure discloses a microfluidic chip, a system and a method for automatic separation and detection of circulating tumor cells. The microfluidic chip includes a density gradient centrifugation assembly, a cell capture assembly, and a reagent storage assembly. The density gradient centrifugation assembly is configured to carry out density gradient centrifugation on a whole blood sample to achieve separation and obtain a plasma layer, a monocyte layer, a Ficoll solution layer, and an erythrocyte and granulocyte layer. The cell capture assembly includes a capture channel, a capture inlet, and a capture outlet. The capture inlet and the capture outlet are in communication with the capture channel. An inner wall of the capture channel is provided with capture holes and negative-pressure capture chambers. Each capture hole is in communication with one negative-pressure capture chamber correspondingly.

Abstract: The disclosure relates to the technical field of virus detection, in particular, to an IgA antibody and a kit capable of specifically recognizing RBD protein. The antibody can be used as a calibrator of IgA antibody against the RBD protein of SARS-CoV-2.