Figure 3

Validation of two-color (808 nm/915 nm) Cytophone performance through spectral identification of conventional PA targets with positive and negative contrasts in vitro using the dynamic vessel phantom. (a) PA traces with the positive contrast peaks from rare indocyanine green (ICG) aggregates in relatively homogenous ICG solution (left) and bright-field image of ICG aggregate (right). (b) Two color PA traces from RBC aggregates in blood with “one color” artifact (left) and bright-field image of RBC aggregate (right). (c) Negative contrast PA peaks from silica beads as white circulating blood clot (CBC) phantoms (left) and bright-field image of a single bead (right). (d) Positive and negative contrast PA peaks from red and white CBCs in blood (left) and bright-field image of mixed red-white CBCs in the blood (right). (e) Two-color positive contrast PA signals from 23-µm magnetic beads in the background of many 8-µm magnetic beads. (f) Two-color positive PA peaks from synthetic ~ 200 µm Hz.