Recently, we developed a method called Nanosensor Chemical Cytometry (NCC), where an optical nanosensor array embedded within microfluidics can be used to interrogate chemical species efflux from individual cells. The cell itself was found to perform as an informative Gaussian lens, projecting both the nIR emission of the single-walled carbon nanotube sensors as well as various cellular physical properties. We found NCC to be able to profile immune heterogeneities at attomolar sensitivity in a completely non-destructive and real-time manner with rate of ~600 cells/hr.

Macrophages are a critical part of the human immune response, and their collective heterogeneity is implicated in disease progression and prevention. Here, we use the NCC technique to profile the heterogeneity of inducible nitric oxide synthase (iNOS) responses from macrophage populations. Parameters measured nitric oxide (NO) efflux and refractive index (RI) changes at a single-cell level. Using NCC, NO was measured with (10−18 mol) sensitivity in a nondestructive and real-time manner with a throughput of exceeding the 200 cells/frame. With lipopolysaccharide (LPS) activation, NO efflux elevated from 342 (σ = 199) to 464 (σ = 206) attomol/cell·hr, in agreement with previously reported Griess assay results. This work provides an efficient strategy for chemical analysis of cell populations for manufacturing and biopharmaceutical engineering.