Acoustically induced sample reorientation for multi-angle OCT

Optical Coherence Tomography (OCT) is a valuable tool for label-free imaging with micrometer resolution. However, conventional approaches to OCT typically image a sample from a single direction or angle, which limits its ability to image structures placed behind strongly attenuating material or deep inside the object. Here we introduce a solution to this problem by adding a small chamber to a spectral-domain OCT setup. Acoustic actuation enables a contact-free levitation and stepwise reorientation of samples such as zebra-fish larvae and tumor spheroids in a controlled and reproducible manner. We further developed a model-based compressive algorithm, which is able to exploit the diverse multi-angle OCT volumes for a 3D-reconstruction with isotropic resolution and estimation of refractive index values. We demonstrate and validate our approach on zebrafish larvae. We believe that our approach represents a powerful enabling tool for developmental biology and for organoid and cancer spheroid research.