An Early Detection Sensor for Cancer

assembled nanowires
FE-SEM image of a nanowire array positioned on a silicon chip. Nanowires can be functionalized off-chip with cancer-specific molecular sensors.

Carcinomas shed cells into the vascular system before they metastasize. What if you could detect those malignant cancer cells in the blood before they had a chance to spread? That’s what Theresa Mayer and her collaborators Christine Keating and Gary Clawson are trying to achieve. They are developing highly specific and highly sensitive RNA sensors built on a CMOS semiconductor chip that are expected to make the detection of early cancers easier and more effective.

Researchers have incorporated functionalized single crystal silicon and metal nanowires that have been optimized to detect cancer cells onto lithographically patterned chips. In a process unique to the Penn State team, the nanowires are optimized chemically off the chip and then incorporated onto the chip through electrofluidic assembly, a process that can precisely control their placement. Mayer’s group uses chemical vapor deposition techniques to make silicon nanowires. The single crystal structure results in high quality sensors. Arrays of silicon nanowires that have been optimized with various cancerspecific oligonucleotides will attach to circulating tumor cells from breast, prostate, and melanoma cancers. "If successful, this biosensing strategy will enable early diagnosis of these cancers and improve treatment success," Dr. Mayer says.

Theresa Mayer is professor of electrical engineering and director of the Nanofabrication Laboratory. Christine Keating is associate professor of chemistry. Gary Clawson, MD, is professor of pathology in the College of Medicine.

This research brief was featured in the brochure Biomedical Materials.