UV Laser Zaps Multiple Tissue Areas Simultaneously

A single UV laser pulse is being used to zap away biological tissue at multiple points at the same time. This technique could advance the study of developmental biology.

Time-lapse microscopy of a fruit fly epithelium in which a single cell is isolated from the remainder of the cell sheet using a single holographically shaped laser pulse. The cell to be isolated is marked with an asterisk in the first frame. Subsequent frames are at 6 s and 70 s after ablation. (Images: Aroshan K. Jayasinghe)

UV lasers are commonly used for cutting into tissue, but the lasers usually make incisions by vaporizing one point at a time in a series of steps. If the initial laser pulse cuts into cells under tension, the tissue could spring back from the incision. This makes precise tasks, such as cutting around a single cell, difficult.

Researchers at Vanderbilt University found a way around this problem by using a computer-controlled hologram to shape the phase profile of the UV pulse — basically applying a patterned delay onto different parts of the beam. When the pulse then passed through a lens, the altered phase profile yielded an interference pattern with bright spots at any user-desired pattern of points. Using this method, which can vaporize up to 30 points simultaneously, the researchers successfully isolated a single cell on a developing fruit fly embryo and observed how the cell relaxed into a shape dictated solely by internal forces.

Time-lapse microscopy progression is color-coded from blue to red to white.

The technique could be applied to other model organisms, such as frogs or zebra fish, to help answer outstanding questions about the mechanical forces at work as organisms grow and change, the team said. This knowledge may, in turn, guide bioengineers searching for ways to grow designer tissue.

This study was described in OSA’s open-access journal Biomedical Optics Express.

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