Particle analyzer with spatial modulation and long lifetime bioprobes

An apparatus for analyzing a sample, comprising:

• a flow channel through which the sample can pass;
• a first light source adapted to illuminate one or more first excitation region(s) of the flow channel with first excitation light, the first excitation light adapted to stimulate a first light emission from particles of a first particle type, the first light emission having a characteristic first response time τ1;
• a detector disposed to receive light from a plurality of first detection regions of the flow channel wherein the one or more first excitation region(s) is a plurality of first excitation regions interspersed with the first detection regions, the detector adapted to provide a detector output based on the received light;
• and
• a spatial filter disposed between the flow channel and the detector, the spatial filter having a pattern of variable transmission such that (a) the first light emission from a given first particle of the first particle type is transmitted to the detector when the given first particle is disposed in any of the first detection regions of the flow channel, and (b) the first light emission from the given first particle is at least partially blocked from reaching the detector when the given first particle is disposed in any of a plurality of first shielded regions of the flow channel, the first shielded regions being interspersed with the first detection regions;
• wherein the first detection regions are spatially separated from the first excitation region(s) by a gap having a first gap dimension;
• wherein the apparatus is configured to isolate the first light emission from a second light emission emitted by a component in the sample when exposed to the first excitation light, the second light emission characterized by a second response time τ2;
• and
• wherein the gap dimension is a function of τ1 and τ2.

A method of analyzing a sample, comprising:

• passing the sample through a flow channel;
• exposing the sample to excitation light in one or more first excitation region(s) of the flow channel, the excitation light being effective to stimulate a first light emission from particles of a first particle type in the sample, the first light emission having a characteristic first response time τ1;
• transmitting the first light emission from a given first particle of the first particle type to a detector when the given first particle is disposed in any of a plurality of first detection regions of the flow channel, the first detection regions being spatially separated from the first excitation region(s);
• and
• at least partially blocking the first light emission from the given first particle from reaching the detector when the given first particle is disposed in any of a plurality of first shielded regions of the flow channel, the first shielded regions being interspersed with the first detection regions;
• wherein for the given first particle, the transmitting is initiated a delay time after an end of the exposing;
• and
• wherein the method is configured to isolate the first light emission from a second light emission emitted by a component in the sample when exposed to the first excitation light, the second light emission characterized by a second response time τ2 shorter than τ1, and wherein the delay time is a function of τ1 and τ2.