Fig. 4. Z-stack two-photon confocal images (dimensions = 508.4 μm × 508.4 μm) of live spheroids containing BMMs (left) with blank particles and (right) with UCNP and NO-donor loaded particles. Spheroids were stained with calcein AM (green). Particles were identified via emission (red) from embedded UCNPs with laser excitation at 810 nm and a pulse energy of 37.5 nJ. The wavelength range for detection of UCNP emission was 420–460 nm.
