Our Equipment
Zeiss LSM 780 Microscope
This microscope supports high-resolution laser scanning confocal microscopic imaging needs. It has a state-of-the-art spectrum detector with high sensitivity, and oil and water immersion high-numerical aperture objectives for examination of live cells and fixed tissue slides. It is equipped with five lasers and transmission light as well.
STORM Super-Resolution Microscope
This home-built Stochastic Optical Reconstruction Microscope (STORM) is housed in Dr. Ma’s laboratory. The STORM system is based on an inverted microscope with 1.49 NA 100x oil immersion TIRF objective. Four lasers – 405 nm, 488 nm, 647 nm diode lasers and 561 nm DPSS laser cover the spectrum of the most commonly used fluorophores. The filter set consists of a multi-band dichroic mirror (FF405/496/593/649) and an emission filter (692/40). Three electron multiplying CCD camera are used for imaging with EM gain set to 255. The sample holder is mounted on a 3D piezo-stage. An infrared 980 nm laser is used in combination with the piezo stage for the axial Zero Drift Correction (ZDC).Apart from single-color imaging, the system is also capable of multicolor imaging in both 2D and 3D cases by using a family of photo-switchable fluorescent probes. Custom written Lab-VIEW programs synchronize the CCD camera with lasers and can periodically activate a sparse subset of fluorophores using corresponding activation laser.
PTI Spectrofluorometer
The PTI (Photon Technology International) spectrofluorometer is a microscope-based dual PMT detector system with Photometrics CoolSNAP ES ratio imaging module for quantitative measurement of intracellular Ca, pH, and membrane potential. It is an essential tool for cell physiology and molecular studies.
BIO-Scan System for Histology and Pathology Images Storage and Archive
We have a home-made Zeiss Axiovert 200 Bio-Scan system that is built on an inverted Zeiss Axiovert 200 epi-fluorescent microscope. It has 10x, 20x, 40x dry lens and a CCD camera with motorized XY stage. The installed Olympus Cell-Sens Dimension slide reading/archive software allows control of the stage at XY to perform whole slide reading with up to 100x100 montage function.It is thus a very useful tool for both immunohistochemistry and pathology imaging and serves as an archive for storage of large pathological data in a digital format. Through this system, we can share pathological information among research teams.
PALM MicroBeam Laser Capture System
This core houses PALM MicroBeam with Laser Microdissection and Pressure Catapulting technology for noncontact and contamination-free microdissection and sample collection. The PALM MicroBeam incorporates lasers of high beam quality interfaced to a microscope and focused through objectives with high numerical aperture to a minimum possible spot size. Thus, processing accuracy under 1 μm can be reached, enabling the user to manipulate at the level of single cells or even subcellular components.The cutting procedure is performed quickly and is devoid of heat transfer. Adjacent biological matter or biomolecules (i.e., DNA, RNA, or proteins) out of the focus areas are not affected. After the cutting procedure, the selected area is ejected from the object plane with a single laser pulse. The desired piece of interest is transported for several millimeters against gravity, directly into a capture device.
Our Innovative Imaging Methods
In addition to the conventional Zeiss LSM 780 Microscope, our STORM super-resolution imaging platform has made significant progress by developing several innovative methods of data acquisition, analysis, and image reconstruction. Single-molecule localization microscopy achieves sub-diffraction-limit resolution by localizing a sparse subset of stochastically activated emitters in each frame. Its temporal resolution is limited by the maximal emitter density that can be handled by the image reconstruction algorithms. We developed a new algorithm (MempSTORM) based on two-dimensional spectrum analysis. With the same localization accuracy and recall rate, MempSTORM is 100 times faster than the conventional compressive-sensing-based STORM algorithm.
We also developed a 3D high-density super-resolution imaging platform that allows us to precisely locate the positions of emitters, even when they are significantly overlapped in three-dimensional space.
Moreover, we assembled a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improved the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle.
We also developed a 3D high-density super-resolution imaging platform that allows us to precisely locate the positions of emitters, even when they are significantly overlapped in three-dimensional space.
Moreover, we assembled a new image reconstruction algorithm based on tracklets, short trajectories of the same objects. We improved the localization accuracy by associating the same emitters from multiple frames to form tracklets and by aggregating signals to enhance the signal to noise ratio. Using this method, for the first time, we resolve the transverse tubule structure of the mammalian skeletal muscle.