Movies 

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Neuronal Growth Cones Respond to Axonal Damage 

Response of a growth cone to the localized irradiation of a second nearby axonal shaft. The growth cone can be seen to extend multiple filopodia toward the damage site on the irradiated axon, some of which contact the axon. The filopodia subsequently regress. (Link)




A Photon-Driven Micromotor can Direct Nerve Fibre Growth 

We have developed an optical-based system to control the direction of growth of individual axons (nerve fibres) using laser-driven spinning birefringent spheres. One or two optical traps position birefringent beads adjacent to growth cones of cultured goldfish retinal ganglion cell axons. Circularly polarized light with angular momentum causes the trapped bead to spin. This creates a localized microfluidic flow generating an estimated 0.17 pN shear force against the growth cone that turns in response to the shear. The direction of axonal growth can be precisely manipulated by changing the rotation direction and position of this optically driven micromotor. (Link)




Primate Sperm Competition: Speed Matters 

Researchers at the Cellular Biophotonics Laboratory have found evidence that supports the theory that all reproductive competition during the evolution of primate species has occurred at the level of sperm cell motility (21.7 MB) (wmv)




DNA Microablation and Repair Protein Recruitment 

Using a focused 532 nm picosecond green laser source, U2OS DNA was damaged and GFP tagged NBS1 DNA repair protein was visualized recruiting into the laser-irradiated zone over a twenty minute period post-irradiation (7.4 MB) (avi)

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RATTS - Chimpanzee 

This movie demonstrates the RATTS system used to perform experiments done on chimpanzee sperm in real time. The chimpanzee sperm is tracked and trapped. Once trapped, the laser power decays. The sperm escapes the trap after approximately 5 seconds of being held in the trap. This movie in comparison to the next movie shows the extreme difference between sperm from multi-partner mating primates (chimp sperm, fast and strong) and single partner mating primates (gorilla sperm, slow and weak). (39.3 MB) (avi)




RATTS - Gorilla 

This movie demonstrates the RATTS system used to perform experiments done on gorilla sperm in real time. The gorilla sperm is tracked and trapped. Once trapped, the laser power decays. The sperm escapes the trap after approximately 10 seconds of being held in the trap. This movie in comparison to the previous movie shows the extreme difference between sperm from multi-partner mating primates (chimp sperm, fast and strong) and single partner mating primates (gorilla sperm, slow and weak). (47 MB) (avi)




Chromosomal Micromanipulation 

Over the last fifty years many major advances in the fields of photonics and biophotonics have allowed for the development of a wide array of subcellular "tools".  In this video, researchers at the Cellular Biophotonics Lab use "laser scissors" to microablate an individual chromosome.  Then two "laser tweezers" are used to optically move the sliced chromosomes apart. (6.58 MB) (avi)




Cell Fusion 

In this video "laser tweezers" are used to hold two cells close while "laser scissors" are used to open up the membrane, allowing for the fusion of the two cells. (3.34 MB) (avi)




Optical Sperm Trapping 

By manipulating the properties of light, small particles and cells can be optically "trapped".  In this video, researches show the optical strength of a trap by using it to trap human sperm. (3.69 MB) (avi)




Microtubule Polymerization 

In this video microtubule polymerization can be visualized after single microtubules are microablated.  The growth and collapse of the microtubule are highlighted by the black dots. (2.87 MB) (avi)




Microablation of the Zona Pellucida 

Laser scissors can be used to carve into thick the zona pellucida of an egg to aid in fertility (5.93 MB)(avi)




Transpacific Real Time Sperm Tracking 

At the Cellular Biophotonics Lab at UCSD, real time biology experiments can be conducted over the internet. In this video, the Realtime Automated Track and Trap System (RATTS) at the University of California, San Diego (USA) was controlled over the internet by the University of Queensland (Australia). The sperm (in the rectangle) is first tracked by the image-recognition algorithm, moved back to the center of the field (by moving the microscope stage) when it reaches the edge, trapped with a laser tweezers, and then released from the trap and tracked again. This system includes a fully customized tracking algorithm which incorporates cutting edge biophotonics, robotics, and microscopy technology. (7.51 MB) (avi)