Longitudinal monitoring of controlled delivery of basic fibroblast growth factor (VEGF) and angiogenesis in acoustically responsive scaffolds (Conference Presentation)

A multi-modality imaging system integrating photoacoustic microscopy (PAM), fluorescence microscopy (FM) and optical coherence tomography (OCT) was developed and applied for longitudinally monitoring the delivery of basic fibroblast growth factor (bFGF) in a hydrogel matrix through a murine window model, providing comprehensive depiction within the scaffold and surrounding tissue. A flexible intravital imaging window was opened for hydrogel implantation and longitudinal observation. Here the fluorescently labeled bFGF was encapsulated in acoustically responsive droplets, and released by acoustic droplet vaporization (ADV). FM showed the release and diffusion of bFGF. Additionally, angiogenesis induced by bFGF was observed by PAM, correlating with release results visualized by FM. Finally, OCT captured the morphology of hydrogel and surrounding tissue, presenting the degradation of the hydrogel scaffold. The structure and perfusion of blood vessels were validated by histological analysis.