Gage Greening Publishes Honors Thesis Research in Top Journal

Gage Greening (right) with his faculty mentor, Dr. Timothy Muldoon.

The diffuse reflectance and spectroscopic microendoscope (DRSME) includes an LED, laser, reflecting mirrors and light filters.

An optical tissue phantom (2.5 cm thick) used to test the DRSME. The probe tip of the endoscope is in contact with the phantom and delivering blue LED light and red laser light to the optical tissue phantom.

The endoscopy probe of the DRSME delivering blue LED light and red laser light. The goal is to eventually use this endoscopy probe in mouse tissue and human tissue.

The entire endoscopy probe of the DRSME. The distal endoscope probe tip (left) can be placed in direct contact with a sample, either phantoms or real tissue. On the right, the proximal end of the endoscope probe.

Photo by Kristen Coppola

Gage Greening (right) with his faculty mentor, Timothy Muldoon.

Recent biomedical engineering graduate Gage Greening developed a new, non-invasive tool for early diagnosis of oral cancer in his honors thesis. Greening is now a graduate student at the U of A, and recently published part of his honors undergraduate research in the Journal of Biomedical Optics, one of the top journals in his field.

“I haven’t worked anywhere else where I had an undergraduate take the lead on a project,” said mentor Timothy Muldoon, assistant professor of biomedical engineering. “Gage was really good at taking the reins of the project –– it’s hard to teach that.”

Greening developed a microendoscope that would deliver infrared light to a small area of epithelial tissue. A camera captures the light that scatters back out.

“Cancerous and precancerous tissue will scatter and absorb light differently than normal, healthy tissue," Greening said.

To test and fine-tune the system, Greening created “optical tissue phantoms” –– tissues synthesized from a kind of silicon rubber, which vary in thickness from one-tenth of a millimeter (about half the diameter of a human hair) to five centimeters.

The paper, “Characterization of thin poly(dimethlysiloxane)-based tissue-simulating phantoms with tunable reduced scattering and absorption coefficients at visible and near-infrared wavelengths,” focused on the development of these synthetic tissues.

“It was my first paper, so the biggest challenge was learning to address the reviews and communicate with my reviewers,” Greening said. The extra experiments suggested by the reviewers more than tripled the length of the paper, but Greening wasn’t daunted. He is currently working on a second paper based on his honors thesis.

Greening also recently presented his research at the 2015 SPIE Photonics West Conference in San Francisco.

“It’s pretty awesome for a first-year graduate student to get a talk at a major conference,” Muldoon said. “It was born out of his Honors College project, which definitely got him going quickly out of the gate.”

Greening and Muldoon plan to begin testing their system on mice soon. Muldoon estimates that they are about a year away from testing on human tissue.

“There’s the technical issue of getting it to fit in a box and run off of a laptop,” Muldoon said. “Those are reasonable challenges that we can overcome.”

Greening was first author and Muldoon was senior author of the paper. Other coauthors on the paper included:

• Kartik Balachandran, University of Arkansas
• Darren Roblyer and Raeef Istfan, Boston University
• Mark C. Pierce and Laura Higgins, Rutgers University

Honors College research and travel grants supported Greening’s research.