Time-Lapse | Time-Lapse
Key Words: FRAP, FLIP, FRET, TIRF, Biostation, digital imaging, cell culture, cellogy, CCD camera, environmental control, focus
Definition:Time-lapse imaging involves capturing images of dynamic events at predetermined time intervals (milliseconds, minutes, hours, days). These can them be replayed at speeds that enable easier interpretation
Time intervals between image capture can be preset on the camera or through integrated camera / microscope software. Imaging very rapid events demands a high temporal resolution camera to capture detail (capture rates of100 frames/sec or more) and high sensitivity to capture enough signal within a very short time. Cooled CCD detectors limit background noise so that weak signals, such as low-level fluorescence, can be captured more easily. However, rapid, high resolution imaging can be limited by data acquisition capabilities.
Time-lapse imaging can be compromised by minute changes in the microscope set up (temperature fluctuations / vibrations) that affect focus. In live cell imaging, in addition, factors such as cell environment on the microscope, (temperature, pH, humidity) and illumination-caused photobleaching and phototoxicity can constrain time-lapse imaging because of cell damage. Cell motility and bulging may also affect focus - a problem that can be addressed by taking several image series in the Z-plane (using confocal techniques).
Time-lapse imaging is applicable to any microscopy technique used to image dynamics events. It is widely used to image biological events on the macroscopic scale and microscopic live cell dynamic events using techniques such as TIRF, FRAP, FLIP and FRET. It is also used in industrial environments to study materials, e.g., crystallisation events, fatigue testing, erosion.
Time-lapse imaging can be carried out on any microscope system capable of accommodating a digital imaging camera with time-lapse capability. Time-lapse parameters are a feature of many digital cameras designed for microscopy and all confocal imaging systems (the LiveScan Swepfield system is not suited for reflectance studies).
For live cell imaging: For single time lapse experiments BioStation IM offers the ideal controlled and monitored incubator/imaging environment to reduce disturbance to cells and preserve cell health. The BioStation CT, in addition, offers the capability to carry out multiple experiments under the same environmentally controlled conditions.
For live cell confocal imaging: Nikon's Ti with built in Perfect Focus System (PFS) E2000FPS with and LiveScan Sweptfield confocal system or A1R confocal system. The LiveScan Sweptfield confocal incorporates a high resolution, high sensitivity cooled CCD detector with up to 90% quantum efficiency, ideal for imaging low light and rapid intracellular events. The A1R's hybrid scanning system allows photoactivation and fluorescence imaging to be conducted simultaneously (without the need for a separate laser unit). A resonant scanner, in addition, captures images at high speed to record rapid changes after photo activation. The Ti's PFS E2000FPS (perfect focus system) continually and automatically corrects focus to compensate for infinitesimal changes in the microscope set up during time-lapse imaging. PFS is compatible with a wide range of observation methods (for example, brightfield, fluorescence, DIC , TIRF , phase contrast).