Magnetically actuatable 3D-printed endoscopic microsystems.

In endoscopy, there is a crucial demand for compact system designs to allow for imaging in narrow spaces and reduce the risk of damage during endoscopic procedures. Enhanced functionality of lensed endoscopes can be realized by integrating actuatable imaging systems with flexible fiber bundles. Conventionally fabricated actuatable endoscopes are, however, limited in their miniaturization capability, typically resulting in system diameters greater than 1 mm. In this work, we present highly compact magnetically actuatable 3D-printed and endoscopically integrated microsystems that are fabricated on the end-facet of imaging fiber bundles using two-photon polymerization. Electromagnetic microcoils affixed to the fiber bundles are utilized to stimulate embedded polymer-magnets to achieve axial, lateral, or rotatory displacement of microoptical elements leading to zooming, resolution enhancement, and increased field of view capabilities. All demonstrated systems achieve overall system diameters well below 900 µm, marking a distinct advancement in the miniaturization of actuatable endoscopic devices. This work demonstrates the feasibility of integrating highly functional and compact optical systems within endoscopes, unlocking new potential for their application in diverse fields, for example in minimally invasive ("keyhole") surgery or intravascular imaging.