Microimager: a flexible thin-film miniaturized endoscope for optical biomedical imaging

Optical imaging is the gold standard for visualizing the structure and function of biological tissue. Non-invasive imaging methods can only reach a limited depth while providing a high spatial resolution. On the other hand, implantable imagers that can access deep tissue are prohibitively large and invasive. Here, we present the Microimager, a flexible, miniaturized thin-film endoscope (7 × 400 μm) featuring multiple independent channels for high-resolution light delivery and collection from deep tissue. The Microimager consists of an array of parylene photonic waveguides implemented using a scalable microfabrication process. We experimentally demonstrate spatial discrimination and imaging of 30 µm features on a resolution mask, as well as distinct regions in mouse brain tissue. The Microimager is a useful addition to the optical biomedical imaging toolset and can provide access to deep tissue in a minimally invasive way for a wide range of applications.