Ultrathin monolithic 3D printed optical coherence tomography endoscopy for preclinical and clinical use.

Preclinical and clinical diagnostics increasingly rely on techniques to visualize internal organs at high resolution via endoscopes. Miniaturized endoscopic probes are necessary for imaging small luminal or delicate organs without causing trauma to tissue. However, current fabrication methods limit the imaging performance of highly miniaturized probes, restricting their widespread application. To overcome this limitation, we developed a novel ultrathin probe fabrication technique that utilizes 3D microprinting to reliably create side-facing freeform micro-optics (<130 µm diameter) on single-mode fibers. Using this technique, we built a fully functional ultrathin aberration-corrected optical coherence tomography probe. This is the smallest freeform 3D imaging probe yet reported, with a diameter of 0.457 mm, including the catheter sheath. We demonstrated image quality and mechanical flexibility by imaging atherosclerotic human and mouse arteries. The ability to provide microstructural information with the smallest optical coherence tomography catheter opens a gateway for novel minimally invasive applications in disease. A 3D printed endoscope less than half a millimeter in diameter provides high-resolution images inside narrow arteries without damaging tissue. Miniaturized endoscopes hold great potential for imaging delicate organs, but it is difficult to achieve high-quality imaging with very small components. Jiawen Li at University of Adelaide, Australia, Simon Thiele at University of Stuttgart, Germany, and co-workers used laser 3D microprinting to produce optical components just 125 micrometers in size, including a miniaturized prism that focuses and directs light, and corrects aberrations. This periscope-like design collects 360-degree images by rotating inside a transparent catheter sheath that protects the surrounding tissue. The researchers tested the endoscope by imaging the inside of fresh human and mouse arteries that were severely narrowed by plaque build-up from atherosclerosis, suggesting it could identify risk factors for heart attacks and strokes.