Nanoscopy with cheap, traditional microscopes
Image: Standard resolution (left) compared to high resolution and super-resolution (right) obtained with chip-based method. [Bielefeld University/Robin Diekmann]
Physicists at Bielefeld University, Germany, and Norway-based University of Tromsø have developed a photonic chip for performing super-resolution light microscopy with conventional microscopes.
While today's so-called nanoscopy techniques use a complex microscope for imaging alongside a simple glass slide to hold the sample, the researchers' method instead uses a complex, but mass-producible chip, to host the sample, with a low-cost microscope.
Here, a probe is illuminated directly on the specimen slide-sized chip, with a lens and a camera recording the signal perpendicular to the chip.
Crucially, the photonic chip provides a waveguide for the illumination source, producing a strong evanescent field that is used for single-molecule switching and fluorescence excitation.
The set-up enables chip-based single molecule localisation microscopy as well as fluctuation-based super-resolution imaging on a conventional microscope.
And as the chip-based nanoscopy separates the illumination and detection paths, total-internal-reflection fluorescence excitation is possible over a large field of view.
As researcher Dr Mark Schüttpelz from Bielefeld University highlights, data can be reconstructed as super-resolved images with a markedly higher resolution than that obtained with conventional microscopy.
What's more, the use of photonic chips now makes it possible to visualise more than 50 cells in a single super-resolution image.
"Our approach to resolution-scalable nanoscopy allows for localization-based, as well as fluctuation-based, super-resolution imaging on a simple set-up that only demands coupling of the excitation light source into the waveguide," says Schüttpelz.
"Using a ×20 objective lens, a field of view of around 0.5 mm width can be imaged at a resolution of some 340 nm in less than 25 seconds... which will also enable live-cell applications," he adds.
The researchers have used their method to image fenestration in liver sinusoidal endothelial cells.
"The invention of the new chip-based superresolution technique is a paradigm shift in microscopy, and it will now permit a much broader use of nanoscopy in science, research, and everyday applications," concludes Schüttpelz.
Research is published in Nature Photonics.