Methods, systems, and apparatus for performing flow cytometry

摘要

Disclosed is an apparatus and method for detecting an analyte in a fluidic sample. Flow cytometric sorting methods used to label and differentiate between cells can adversely affect the viability of the cells. The apparatus comprises an illumination source (151); concave collector element (146); closed flow cell and a detector (150). The illumination source (151) generates electromagnetic energy (149) to illuminate the sample at an interrogation region (148). The concave collector element (146) comprises a vertex; an optical axis and a focal point. The interrogation region (148) is coincident with the focal point of the concave collector element (146). The closed flow cell comprises a sample inlet; sample outlet and a flow path (138). The flow path (138) is defined between the sample inlet and outlet. The flow path (138) passes through the interrogation region (148) and a sorting region (152) disposed downstream of the interrogation region (148). The portion of the flow path (138) which passes through the interrogation region (148) is coaxially aligned with the optical axis of the concave collector element (146) and wherein at least the portion of the flow path (138) passing through the interrogation region (148) and the sorting region (152) is bounded by a flow cell wall to form a continuous closed flow path without division or bifurcation. The sample flows as a core-in-sheath flow or laminar flow at least through the interrogation region (148). The sample has a direction of flow moving from the interrogation region (148) towards the vertex of the collector element (146) or a direction of flow moving from the vertex of the collector (146) towards the interrogation region (148) and a portion of the flow path (138) passes through an internal volume of the collector element (146). The analyte generates a detectable signal in response to illumination. The detector (150) detects the detectable signal. The illumination source may be dispersed by a conical optical element (not labelled), reflected by a first (210) and second (212) concave optical elements to the interrogation region (148). The detectable signal generated from the interrogation region may be focused by the collector element (146) towards the detector (150). A pinhole element (216) may be placed at the focus of the transmitted energy to filter the detectable signal before being allowed to illuminate the detector (150).