Figure 5: Synthesis of NIR-active anisotropic particles.

(a) NIR-active triangular particle synthesis. NIR emitting CdTeSe/ZnS QDs were physically entrapped in NOA polymer particles produced in an NOA device. (b) Fluorescent signal intensity as a function of quantum dot loading concentration. Fluorescence was integrated over a circle of radius 30 μm centred on the triangular particles. Each point represents mean measurement from three particles; error bars represent standard deviation. (c) NIR-active multifunctional encoded particle synthesis. Using Tergitol for inert flows, Janus particles were created with a graphical barcode bearing NIR emitting QDs and a separate probe region embedded with single-walled nanotubes (SWNTs) for label-free H⁺ detection. The structured microflows were prepared by the process described in Supplementary Fig. S10. (d) DIC and NIR photoluminescence images of particles from (c). (e) Shift in emission spectrum of embedded SWNTs on introduction of 2.4 M HCl. Blue arrow indicates most pronounced shift, produced by (8,7)-type SWNT. (f) Intensity decay for (8,7)-type SWNT during H⁺ detection. Exponential quenching model was fit to the experimental data, providing moderate proton quenching kinetic parameters of 0.01 and 0.02 s⁻¹ for 0.6 and 2.4 M, respectively. All scale bars, 50 μm.