Paired together, they can map the distribution of stiffness in a given tissue and systematically use "guesses and checks" to find which tissue stiffness map best models the response they actually see in testing.
The process involves thousands of these "guesses" and therefore requires powerful supercomputers like Stampede at the Texas Advanced Computing Center (TACC), one of the most powerful in the world.
After numerous computer studies, the team has begun to experimentally validate this model using gelatin tissue phantoms (similar to Jell-O) with and without stiffer "tumors." They have been running indentation experiments to measure surface displacements on the tissue and identify tumor locations. They presented their work, which is supported by the National Science Foundation, at the 2016 Inverse Problems Symposium.
"This system has the potential to significantly increase the early detection of breast cancer with no unnecessary radiation, essentially no risk, and with little additional cost," Olson said.
DESIGNING NANOSCALE DNA-READERS
Olson, Throne and Nolte's electromechanical technique works on the surface of the body, but an emerging class of nano-scale sensors aims to diagnose cancer from within the body.
Nanosensors must be small and sensitive, targeting specific biomarkers that may indicate the presence of cancer. They must also be able to communicate that information to an outside observer. Scientists and sci-fi authors have long predicted the rise of nanosensors, but only recently has it become feasible to engineer such technologies.
A number of scientists have been using TACC's supercomputers to investigate aspects of this problem. One such researcher is Aleksei Aksimentiev, a professor of biological physics at the University of Illinois, Urbana-Champaign. Aksimentiev focuses on creating silicon nanopore devices that can sequence DNA inside the body to detect the telltale signs of cancer or other diseases.
A nanopore is essentially a tiny hole in a very thin membrane, through which an even smaller particle, like DNA, can pass. In addition to being precisely shaped, it must be able to attract the right molecules and induce them to pass through the pore so they can be genetically sequenced and identified.
Writing in ACS Nano in December 2016, Aksimentiev and bioengineering professor Li-Qun (Andrew) Gu from the University of Missouri's Dalton Cardiovascular Research Center described efforts to detect genetic biomarkers using nanopores and synthetic nanocarriers. The nanocarriers selectively bind to target biomolecules, and increase their response to the electric field gradient generated by the nanopore, essentially forcing them through the hole.
