In high-resolution biological imaging, achieving the right balance between clarity, spatial resolution, and depth of field remains a constant challenge. We are excited to share a recent application of our Delta 7 series during a visit to ICFO in Barcelona, in collaboration with Prof. Pablo Loza-Alvarez and Dr. Gustavo Castro at the SLN Lab.
The experiment focused on improving the imaging of pig sperm cells using a custom light-sheet microscopy setup. Imaging sperm cells requires high spatial resolution, especially to resolve the fine morphology of the sperm tail. However, this structure can easily be obscured by optical aberrations and the limited depth of field of the microscope.
To address this, we integrated two Delta 7 refractive wavefront modulators into the light-sheet microscope: one in the illumination path and one in the detection path. This allowed us to optimize both sides of the optical system.
The custom setup uses low-magnification Nikon objectives for both illumination and detection. The sample is placed inside a tube surrounded by water. In this configuration, a Delta 7-10 was positioned in the illumination path behind the 10x objective, while a Delta 7-20 was placed behind the 16x Nikon objective in the detection path.
Our team visited ICFO to integrate both Delta 7 devices into the existing custom-built light-sheet microscope. The Delta 7-10 was mounted using a 30 mm cage system, with the Nikon 10x objective screwed directly onto it. The Delta 7-20 was integrated in a horizontal orientation and mounted on top of a Z-stage using our adapter solution, allowing the Nikon 16x objective to be attached directly above it.
The full mechanical integration into the existing setup was completed in less than one hour.
For the first proof-of-principle experiment, we used Phinden, our image-based wavefront sensorless aberration correction software, to correct for system and sample-induced aberrations. The comparison shows the image before correction on the left and after correction on the right.
At the centre of the image, a pig sperm cell is visible. After correction, the sperm head appears brighter, and the tail structure becomes finer and more clearly resolved. This improvement makes it possible to observe details in the tail that were previously difficult to distinguish. The intensity profile further confirms this improvement: the tail signal becomes brighter and narrower, indicating a reduction in FWHM.
In parallel, the Delta 7 in the illumination path was used to modulate the light sheet, improving image contrast across a wider field of view.
This first experiment demonstrates how adaptive optics can enhance light-sheet microscopy by improving image quality and revealing fine biological structures that are otherwise hidden by aberrations.
For a deeper technical background on the employed light-sheet microscopy techniques developed by Prof. Pablo Loza-Alvarez’s group, see the following publications:
