Fig. 4.

MSOT signal in gastrointestinal organs after oral gavage of either PLA-BSA-AF680 particles or BSA-AF680 alone. (Top) MSOT imaging demonstrates nanoparticle localization and uptake in the proximal small bowel (PSB), distal small bowel (DSB), proximal colon (PC), and mesenteric lymph node (ML) over the course of 48 h as indicated using arrows. (Bottom) BSA-AF680 was undetectable after 1 h post gavage. Areas of the small bowel, colon, and mesenteric lymph node are circled in the BSA-AF680 treated image. Deoxy-hemoglobin is shown in blue and BSA-AF680 in the hot color bar. All mouse images were equalized to the same intensity scale bar.