Photoacoustic microscopy reveals deep angiogenic responses in 3D bioprinted tumor-vessel models.

Three-dimensional (3D) tumor-vessel models provide a physiologically relevant platform to study tumor-induced angiogenesis and evaluate therapeutic responses. However, imaging-based analysis of these models is often constrained by limited penetration depth and volumetric resolution. To overcome these challenges, we employed high-resolution photoacoustic microscopy (HR - PAM) to monitor and quantify angiogenesis within bioprinted tumor-vessel models under drug treatments. Compared to confocal microscopy, the PAM achieved a 1.6-fold increase in 1/e² penetration depth, enabling visualization of vascular structures up to ~1 mm in depth. Using our HR - PAM platform, we successfully monitored and quantified tumor-induced angiogenesis, and following treatment with antibiotics, observed significant suppression. This deep tissue and large-volume PAM platform provides enhanced 3D insights into the effects of antibiotics on angiogenesis, paving the way for more precise in vitro evaluations of therapeutic interventions and drug screening studies.