• Real-time automated tracking and trapping system for sperm
    with L. Z. Shi, C. Chandsawangbhuwana, M. W. Berns, and E. L. Botvinick
    We have developed a microscope system for real-time single sperm tracking with an automated laser tweezers escape power assay. Phase contrast images of swimming sperm are digitized to the computer at video rate. The custom algorithm creates a region of interest centered about a sperm in response to a mouse click and performs all subsequent tasks autonomously. Microscope stage movement responds to feedback from video analysis of swimming sperm to center the sperm with respect to the field of view…Read more
  • Use of laser tweezers to analyze sperm motility and mitochondrial membrane potential
    with L. Z. Shi, C. Chandsawangbhuwana, J. Tam, B. Durrant, E. L. Botvinick, and M. W. Berns
    We combine laser tweezers with custom computer tracking software and robotics to analyze the motility [swimming speed, VCL, and swimming force in terms of escape laser power ] and energetics [mitochondrial membrane potential ] of individual sperm. Domestic dog sperm are labeled with a cationic fluorescent probe, DiOC 2, that reports the MP across the inner membrane of the mitochondria located in the sperm's midpiece. Individual sperm are tracked to calculate VCL. Pesc is measured by reducing the…Read more
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    Automated Motile Cell Capture and Analysis with Optical Traps
    with B. Shao, L. Z. Shi, and E. L. Botvinick
    Laser trapping in the near infrared regime is a noninvasive and microfluidic-compatible biomedical tool. This chapter examines the use of optical trapping as a quantitative measure of sperm motility. The single point gradient trap is used to directly measure the swimming forces of sperm from several different species. These forces could provide useful information about the overall sperm motility and semen quality. The swimming force is measured by trapping sperm and subsequently decreasing laser…Read more
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    Erratum: Analysis of sperm motility using optical tweezers 11:5 )
    with E. L. Botvinick, L. Z. Shi, B. Durrant, and M. W. Berns
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    Computer-based tracking of single sperm
    with L. Z. Shi, M. W. Berns, and E. L. Botvinick
    This paper describes a robust single sperm tracking algorithm that can be used in laser optical trapping and sperm motility studies. The algorithm creates a region of interest centered about a sperm selected by the user. SSTA contrast enhances the ROI image and implements a modified four-class thresholding method to extract the tracked sperm as it transitions in and out of focus. The nearest neighbor method is complemented with a speed-check feature to aid tracking in the presence of additional …Read more
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    An automatic system to study sperm motility and energetics
    with L. Z. Shi, C. Chandsawangbhuwana, E. L. Botvinick, and M. W. Berns
    An integrated robotic laser and microscope system has been developed to automatically analyze individual sperm motility and energetics. The custom-designed optical system directs near-infrared laser light into an inverted microscope to create a single-point 3-D gradient laser trap at the focal spot of the microscope objective. A two-level computer structure is described that quantifies the sperm motility and energetics using real-time tracking and fluorescent ratio imaging. The communication bet…Read more