Figure 5. Super-multiplexed optical barcoding with polyynes.

(a) Polymer beads are readily encoded by combinatorial loading of polyynes. Inset shows the bright-field image of barcoded polystyrene beads. (b) Spectral barcoding of polyynes at 10 frequencies and 3 intensities (0, or 1 or 2) with SRS readout, which can obtain 3¹⁰-1=59048 distinct barcodes. (c) Cells are labeled with multiple encoded beads, as shown by the bright-field images. The barcode information is well preserved in live HeLa cells with clear readout by spontaneous Raman measurement. (d) Rapid decoding and spatial visualization of bead identities with SRS microscopy. Left: 2940 cm⁻¹ image of unidentified beads inside living HeLa cells; Right: decoded beads in the field of view by hyperspectral SRS imaging at characteristic frequencies. The color of each bead (six different types) in the decoded map corresponds to the spectral barcode in (c).