Zapping Individual Cancer Cells

July 10, 2008 — -- Engineers at the University of Texas at Austin have patented a laser microscalpel that allows a surgeon to operate on tissue one cell at a time, precisely targeting disease while leaving healthy surrounding cells alive.

The device combines two technologies--a femtosecond laser and two-photon fluorescence microscopy--into a single miniaturized, flexible probe. The probe can target single cells in three-dimensional space, penetrating up to 250 micrometers into tissue.

The probe could be a significant advance for endoscopic surgery that requires high precision, such as destroying cancer cells scattered throughout brain tissue or operating on delicate tissue like vocal cords without damaging them, says Adela Ben-Yakar, an assistant professor of mechanical engineering at the University of Texas at Austin. Ben-Yakar developed the microprobe along with Stanford University associate professor Olav Solgaard and with Chris Hoy, a graduate student in Ben-Yakar's lab. The research was published in the June 23 issue of Optics Express.

Small, flexible laser tools are often used in endoscopic surgery to vaporize unwanted tissue. But although they offer greater precision than conventional scalpels, the existing laser tools tend to generate a lot of heat, causing damage in the areas surrounding the targeted tissue. "Current technology is really blasting everything around, causing extensive damage," says Ben-Yakar.

In contrast, femtosecond lasers use less energy than conventional laser-surgical tools, and thus generate less heat in surrounding tissue. Because they are able to destroy targeted cells without causing damage outside the target area, they are beginning to be used for surgery that requires great precision: since 2003, ophthalmologists have used femtosecond laser microscope tools to perform eye surgery. But the tabletop lasers currently in medical use are bulky, so their use is restricted to surface areas of the body, such as the skin or eye.

Likewise, two-photon fluorescence microscopy has also found applications in medicine and biomedical imaging as a way to get three-dimensional images of small structures. But until now, no one has combined it with a femtosecond laser in a device small and flexible enough for endoscopic surgery.