New 3D Single-Pixel Imaging Method Used to Image Single Living Cells

Researchers from the Chinese Academy of Sciences (CAS) report that they have improved upon available three-dimensional single-pixel imaging (3D-SPI) methods with an optical single-pixel volumetric imaging approach by 3D light-field illumination, which achieves a near-diffraction-limit 3D optical resolution. Their new method is reportedly capable of label-free 3D visualization of optical absorption contrasts of single living cells

Details on their new approach were published in PNAS last month.

SPI has become an attractive 3D imaging modality. Through single-pixel detectors instead of conventional array sensors, the performance of SPI exceeds the conventional ones in spectral range, detection efficiency, and timing response. Furthermore, the single-cell cameras outperform conventional imaging methods at weak intensity, single-photon level, and precise timing resolution. 3D-SPI techniques generally depend on time-of-flight (TOF) or stereovision to extract depth information. However, existing implementations can only reach a millimeter level at best, which is incapable of imaging microscopic objects like cells.

To exceed the resolution limitation, the team built a 3D-LFI-SPM prototype. As a result, the prototype achieves an imaging volume of ~390×390×3,800 μm³  and a resolution of up to 2.7 μm  laterally and 37 μm  axially. To demonstrate its capabilities, the team performed label-free 3D imaging of living Haematococcus pluvialis cells and successfully counted the living cells in situ.

The new approach can be applied to visualize various absorption contrasts of biological samples. With depth-resolved imaging ability, scientists might be potentially able to monitor cell morphology and growth in situ in the future.