Stimulated emission depletion (STED) microscopy, nanofabrication, bioinstrumentation, femtosecond lasers: Cutting edge, two tunable femtosecond laser based, multifunctional and nanoscopic system including STED, FLIM, FRET, Multiphoton, SHGM and confocal microscope, etc. The system consisted of a Coherent’s Chameleon Ultra II 80MHz (RoHS) Ti:Sapphire tunable femtosecond  laser and Mira OPO – Fan Poled Ring Configuration optical parametric oscillator (OPO), a Nikon’s C2 laser Scanning Confocal Microscope System, and PI’s PInano XYZ P-545.3C7 Piezo Stage with Capacitive Sensors with USB controller, TCSPC / FLIM, Becker & Hickl Inc,  Ultra-low noise single photon detection module, etc.

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Stimulated Emission Depletion (STED) nanoscopy, Super resolution imaging, femtosecond laser

 

Understanding subcellular structures, their functions and interaction between cells and their microenvironment is extremely important in biology, but our knowledge is limited. One of the reasons is that current optical microscopy, which has become an important tool in biological research, has limited resolution. In fact, all conventional optics based measurements and imaging methods suffer from the diffraction limit in physics, and the spatial resolution is limited to roughly half wavelength of the light. Thus, conventional microscopes don’t have sufficiently spatial resolution to study structures and dynamic processes in biology. Furthermore, each type of microscope has limited function and performance. Visible light has limited penetration depth to image tissue and cell microenvironment. Each imaging technique has its own advantage and multimodality imaging allows acquisition of co-registered complementary data from samples and can provide more correlated data. Therefore, this project focuses on the development of (1) super resolution STED nanoscopy to bypass the diffraction limit to achieve high resolution, (2) multimodality bioimaging technology. STED nanoscopy has been an emerging breakthrough technology to overcome the diffraction limit to achieve nanoscale spatial resolution and won Nobel Prize in 2014. Multiphoton microscope can penetrate deep into tissues. Fluorescence lifetime imaging microscope (FLIM) can measure time-resolved dynamics.

 

Our lab has recently developed a tunable, two femtosecond lasers based ultrafast, far field, multimodality nanoscopic system. The system integrates three technologies together, i.e. SETD, nanoscopy, femtochemistry and Lab-on-a-Chip for new discovery and applications in science and engineering. The system includes

•           STED Nanoscopy

•           Multiphoton  (MP) microscopy

•           FLIM (TCSPC / FLIM, Becker & Hickl GmbH)

•           Fluorescence resonant energy transfer (FRET)

•           Second harmonic generation microscope (SHGM)

•           Confocal microscope

•           Laser induced fluorescence photobleaching anemometer (LIFPA)

•           Integrated these functionalities with Lab-on-a-Chip for live cell imaging.

 

Our large instrumentation system will offer spatially nanoscale and temporally picoseconds resolutions for fundamental research. The same system can also be used for nanophotolithography to fabricate nanostructures. So far, few labs in the world have such an advanced and powerful instrumentation platform.

   

• Yunxia Wang, Zhenhua Bai, Qian Wang, Guiren Wang. Experimental investigations on fluorescence excitation and depletion of carbon dots. Journal of Fluorescence. DOI 10.1007/s10895-017-2082-6. 2017.

• Luo, H., G. Wang & L. Yuan (2019) A special three-layer step-index fiber for building compact STED systems. Scientific reports, 9, 8455-8455.

• C. Kuang, W. Zhao, G. Wang Far-field optical nanoscopy based on continuous wave laser stimulated emission depletion. Review of Scientific Instruments 81, 053709, (2010).