Functional photoacoustic fiberscope with 3D-printed optics (Conference Presentation)

We report a 0.3-mm-diameter fiberscope for minimally invasive endoscopic functional photoacoustic microscopy (PAM). By leveraging direct-laser-writing 3D printing, this device features fiber tip-integrated dual-wavelength light delivery optics and an optical ultrasound sensor, achieving forward-viewing functional imaging with a lateral resolution of 3 µm. We have demonstrated the utility of the PAM fiberscope by imaging the microvascular structure and blood oxygenation in the deep mouse brain in vivo. Also, we have showcased its potential for clinical application by deploying the fiberscope through a clinically used 23-gauge injection needle for functional imaging of the muscle microvasculature in humans.