Nanolive imaging platform offers long-term live-cell imaging

23 Jul 2019

Technology developed at EPFL uses refractive index information to compile 3D images of cells.

Nanolive, a spin-out from the Swiss research institute EPFL, has launched the CX-A microscope system, said to be the first microscope to combine the power of the company's non-invasive 3D imaging technology with automated throughput.

The platform is intended to enable investigation of macro cellular dynamics like cell health, proliferation, movement and function, as well as micro-organelle dynamics and interactions such as those in mitochondrial networks.

"With our microscope, scientists can run experiments under a range of conditions and obtain high-quality images generated using refractive index without adding fluorescent markers," said Mathieu Frechin of Nanolive.

The platform generates images of cells from all angles using their refractive index, employing a rotating laser to illuminate the sample at a 45-degree angle and generating holographic information that can be compiled subsequently into 3D images via bespoke software.

According to Nanolive, the method is non-invasive, interference-free, and the rotational scanning allows for 3D reconstruction with excellent resolution.

In combination with other data sourced from fluorescence imaging, the platform can also enable scientists to follow dynamic and delicate cell processes over time, such as the membrane potential of living subcellular structures like mitochondria. The signals reveal subtle variations in structure and activity that occur in response to drugs or genetic mutations.

Automated analysis

In a 2013 Nature Photonics paper about the research underlying the technique, the authors describe it as tomographic diffractive microscopy, combining microholography with tomography. Varying the illumination angle and measuring the incident waves diffracted by the specimen in the Fourier domain allows the resolution of the overall operation to be increased, with lab trials indicating that a lateral resolution of 90 nanometers was possible when 405 nanometer illumination was employed.

Nanolive, which was spun-out from EPFL the same year with an initial funding round of CHF2.7 million, indicated that the CX-A employs a 520 nanometer source and can image individual organelles with a resolution below 200 nanometers.

"The combination of holography and rotational scanning makes Nanolive a revolutionary technology," commented the company. "Holography offers a unique means to measure cells in their native environment: label-free, non-invasive, manipulation-free, and interference-free. Rotational scanning allows 3D reconstructions, noise robustness, and a resolution far beyond the accepted limit for light."

A key aspect of the platform is its automation of the analysis, and the ability to program multiple imaging regimens within the same plate allowing users to run different applications in parallel. According to Nanolive, hundreds of images can be collected each hour, and the analysis can continue for days or weeks, while cells remain unperturbed in a physiologically controlled environment.

"Every new discovery starts with an unprecedented observation," said Sebastien Equis, Nanolive CTO. "We have created a unique tool to seamlessly follow cells from the macro level of cell populations, down to their individual organelle ecosystem."