Biomedicine meets biophotonics

Over the last 50 years, laser light has become an all-encompassing tool in many areas of science and technology, industrial production, and healthcare. Today, physicians use lasers to improve the quality of life of countless people around the world. Here, Dr Silvia Carrasco talks about biomedical research at ICFO and in particular, the role of super-resolution microscopy

The Institute of Photonic Sciences (ICFO) in Barcelona, Spain is an independent, non-profit, research centre established by the Government of Catalonia, Spain, Department of Universities and Research and by the Universitat Politècnica de Catalunya. Launched in March 2002, ICFO is now a leading international institute for photonic and light science, conducting cutting-edge, wide-ranging research – from telecommunications and information technologies to healthcare. Biomedical research is targeted by an increasing number of unique techniques based on light for advanced imaging aimed at providing new understanding, new solutions, early diagnosis and new therapies, including revolutionary nano-medicine concepts and minimally invasive tools.

Optical light microscopy has now extended the boundaries of cellular imaging into super-resolution with the development of technologies that overcome the resolution limit of traditional light microscopes. These new super-resolution technologies provide dramatically enhanced resolution, enabling two-dimensional and three-dimensional imaging of fixed and/or living specimens, and revealing cellular features previously impossible to see.

It is interested in developing fluorescence imaging techniques with high spatiotemporal resolution and using these techniques to study questions in cell biology, virology, neuroscience and other fields

ICFO hosts a world class Super-resolution Light Microscopy and Nanoscopy (SLN) Facility. The SLN at ICFO is equipped with cutting edge microscopy techniques that are able to operate a step beyond the commercial state-of-the-art equipment available. ICFO performs continuous research and development in most of the advanced light microscopy techniques and provide access and training to all types of users at the forefront of microscopy for the most demanding biomedical applications. Available non-linear optical techniques include:

• Multiphoton – Two Photon Excitation Fluorescence, Third Harmonic Generation, Second Harmonic Generation.
• Fluorescence – confocal multispectral confocal, Fluorescence Lifetime Imaging, Fluorescence Resonance Energy Transfer.
• Optical tweezers and femtosecond nanosurgery.
• Photoactivation (STORM).
• Nanoscopy (STED).
• Single molecule techniques.
• Near-field nanoimaging.
• Plasmonics and nanoantennas.
• Raman and Surface Enhanced Raman Spectroscopy.
• Diffuse optical imaging.
• Photothermal imaging.
• Ultrafast (picosecond and femtosecond) dynamics.

The newly opened Nikon Centre of Excellence for STORM imaging at ICFO represents a key addition to push ICFO’s super-resolution capabilities. Focusing on Stochastic Optical Reconstruction Microscopy (STORM) super-resolution technology, this unique partnership will allow researchers access to groundbreaking super-resolution microscopy systems to advance ICFO’s ongoing cutting edge research in this area.

STORM was developed in the laboratory of Dr Xiaowei Zhuang, a Howard Hughes Medical Institute Investigator, Professor of Chemistry and Chemical Biology, Professor of Physics at Harvard University and distinguished member of ICFO’s scientific advisory board. STORM uses photo-switchable fluorescent probes to temporally separate the otherwise spatially overlapping images of individual molecules, allowing the construction of super-resolution images. Using this concept, two and three-dimensional, multicolour fluorescence images of molecular complexes, cells and tissues with a few tens of nanometers resolution have been achieved. This new form of fluorescence microscopy allows molecular interactions in cells and cell to cell interactions in tissues to be imaged at the nanometer scale.

[caption id="attachment_26153" align="alignright" width="200" caption="Two-colour STORM image of microtubules (green) and mitochondria (red)"][/caption]

N-STORM has been developed by Nikon through a licensing agreement with Harvard University granting Nikon the rights to use the STORM technology and is based on the world renowned Eclipse Ti inverted research microscope, providing dramatically enhanced resolution that is 10 times or better than that of conventional optical microscopes. The system incorporates Nikon’s CFI60 objectives featuring high numerical apertures developed using unique optical design, coatings and manufacturing techniques. Constructing high resolution fluorescence images by overlaying single molecule images from localisation information of fluorophores detected with high accuracy and calculated from multiple exposures, N-STORM is capable of multi-spectral two-dimensional and three-dimensional nanoscopy, with lateral resolution to approximately 20nm and axial resolution to approximately 50nm. It generates much more information from detection of single molecule fluorescence emissions without the need for time consuming serial section acquisition and goes one step further, extending the role of the optical microscope to near molecular level resolution. Two systems have been installed: An Eclipse Ti-E with PFS (Perfect Focus System), TIRF and N-STORM; and an Eclipse TiE with fluorescence. Software control is through Nikon’s NIS-Elements AR with 6D and deconvolution modules and NIS-Elements C with N-STORM analysis.

The newly established Advance Fluorescence Imaging and Biophysics group at ICFO is an inter-disciplinary group that works at the interface of advanced light microscopy techniques and their biological applications. It is interested in developing fluorescence imaging techniques with high spatiotemporal resolution and using these techniques to study questions in cell biology, virology, neuroscience and other fields. Its aim is to elucidate fundamental biological questions that also have important implications for health.

Assistant Professor Dr Melike Lakadamyali joined ICFO as a Cellex Nest Fellow with an interdisciplinary research programme that combines optical techniques with biological applications. Dr Lakadamayali worked with Dr Zhuang at Harvard where her main achievements include developing real-time imaging and single particle tracking techniques for studying influenza virus infection inside living cells. These studies shed light on the cellular and molecular mechanisms of influenza virus entry and trafficking. She also used super-resolution fluorescence imaging techniques to map neuronal wiring in the brain. Dr Lakadamyali's research goal is to develop advanced fluorescence imaging techniques that can be used to answer fundamental questions in biology. She is particularly interested in combining single particle tracking with super-resolution fluorescence imaging to obtain both high temporal and high spatial resolution. Incorporating this method with microfluidic devices will eventually allow high throughput imaging of sub-cellular interactions during endocytosis and membrane transport at the molecular level. With this technique at hand, she hopes to be able to study biology of important organelles such as mitochondria and cellular mechanisms of neurotropic viral infections.

The results of this research programme may have important medical implications as the information obtained can be used to understand mitochondria-related defects in neurodegenerative diseases or develop virus-based gene therapy vectors.

Contact:

www.icfo.es

www.nikonstorm-icfo.com

The Author:

Dr Silvia Carrasco

Director of Department of Knowledge and Technology Transfer at ICFO, Spain