Fig. 2

Evidence of BC particles at the fetal side of the human placenta. WL generation originating from the BC particles (white and further indicated using white arrowheads) under femtosecond pulsed laser illumination (excitation 810 nm, 80 MHz, 10 mW laser power on the sample) is observed. Second harmonic generation from collagen (red, emission 400–410 nm) and TPAF from placental and red blood cells (green, emission 450–650 nm) are simultaneously detected. Scale bar: 100 µm. The boxes on the right show the black carbon particles present in placental tissue at higher magnification. Scale bar: 30 µm