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Delta 7 Adaptive Optics for Enhanced Light-Sheet Microscopy at ICFO, Barcelona

  • 1 day ago
  • 2 min read

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.


LSM system in the SLN Lab with the Delta 7-10 (top) in the illumination path (top) and the Delta 7-20 (bottom) in the detection path (bottom).
LSM system in the SLN Lab with the Delta 7-10 (top) in the illumination path (top) and the Delta 7-20 (bottom) in the detection path (bottom).

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.


Images of pig sperm were taken using an LSM system. The image on the left shows pig sperm without AO correction, and the image on the right shows pig sperm with aberration correction.
Images of pig sperm were taken using an LSM system. The image on the left shows pig sperm without AO correction, and the image on the right shows pig sperm with aberration correction.
Measurement result of the cross-section intensity of the pig sperm tail.
Measurement result of the cross-section intensity of the pig sperm tail.

At the center 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:


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