Inquiries & innovations
By Marcus Woo
Diagnosis on a chip
To diagnose diseases like Ebola, clinicians seek viral or bacterial DNA or RNA in patient samples. Traditionally, tests used for this employ PCR (polymerase chain reaction), a method that induces those molecules to replicate, making them easier to detect.
By eliminating the PCR step, UC Santa Cruz professor of electrical engineering Holger Schmidt and collaborator Brigham Young University professor Aaron Hawkins invented a potentially simpler, quicker, and cheaper way to diagnose diseases.
The lab-on-a-chip device channels a liquid like blood or saliva containing fluorescently labeled, infectious DNA across an optical waveguide, a tiny tunnel that steers light. When light hits tagged DNA, the dye glows, revealing the presence of the pathogen.
“This could hopefully be a new way to do medical testing,” Schmidt said, providing a practical point-of-care tool to use in clinics and the field (see inquiry Vol. 2, 2016-17, A lab in the hand).
Schmidt H, Hawkins AR. Method for amplification-free nucleic acid detection on optofluidic chips. U.S. Patent 9,551,667, filed November 18, 2011, issued January 24, 2017.
Time and place
The Large Hadron Collider (LHC) in Switzerland slams trillions of protons together, each collision producing hundreds of particles spraying in all directions. Particle detectors must then track their trajectories.
But a typical silicon detector can only accurately measure a particle’s position—not how long it’s been traveling. So UCSC professor of physics Abraham Seiden and research physicist and adjunct professor Hartmut Sadrozinski helped design a new silicon detector that does both. Researchers will use the improved detectors to start building a new instrument for the LHC as early as 2021, Seiden said.
The technology could also be used to improve medical imaging systems that doctors use to target and destroy cancerous tumors with proton beams.
Sadrozinski H, Seiden A, Cartiglia N. Segmented AC-coupled readout from continuous collection electrodes in semiconductor sensors. U.S. Patent 9,613,993, filed June 30, 2016, issued March 9, 2017.
In 2013, as part of a senior design engineering class, UCSC students built an LED (light-emitting diode) light bulb that would cost only $5 to make—substantially less than what they sold for at the time.
The experience taught them real-world skills, said Julian Dahan, student lead on the project. “It put us ahead of the curve in job interviews.”
They also discovered a new circuitry design that allowed the brightness of the LED to be controlled with a switch, knob, or even via Wi-Fi. In contrast to most adjustable LEDs now on the market, this adjustability is built right into the LED itself.
“That was the novelty that no one had ever done before,” said David Munday, the lecturer who teaches the class. “Just plug it in and go.”
Munday D, Baker R, Dahan J, Peterson R, Sloan C. Switchable luminance LED light bulb. U.S. Patent 9,730,282, filed August 5, 2015, issued August 8, 2017.
In a living cell
Its tip is so small you can’t see it with an optical microscope. Like a tiny needle, the nanopipette pierces a living cell and extracts contents from its organelle structures—all without harming the cell. The device can also inject biologically relevant chemicals, to test single-cell effects of potential drugs, for example.
No other technology can examine a cell in this way without killing it, said UCSC professor of biomolecular engineering Nader Pourmand (see inquiry Vol. 1, 2015-16, Single cell technology). The nanopipette provides a powerful tool to study how a living cell changes and behaves.
His lab uses the nanopipette to study how a variety of dynamic processes within single cells contribute to degenerative brain diseases and drug resistance in cancer, Pourmand said.
Karhanek M, Webb CD, Umehara S, Pourmand N. Functionalized nanopipette biosensor. U.S. Patent 9,766,204, filed January 22, 2015, issued September 19, 2017.
Technology developed at UCSC underlies the MinION (see inquiry Vol. 3, 2017-18, Genes to go), a handheld gene sequencer manufactured by Oxford Nanopore Technologies (Oxford, U.K.). The MinION reads sequences via nucleotide-specific changes in ion current as DNA strands pass through a nanopore, a tiny hole in a polymer membrane. The nanopore approach has led to smaller, faster, and cheaper devices, expanding access to sequencing and invigorating genome research.
UCSC professor of biomolecular engineering Mark Akeson and collaborators have now devised a novel method that applies voltage to move a DNA strand back and forth through a nanopore at a controlled rate.
The invention could be useful for new sequencing technologies, Akeson said. “It’s a terrific way to couple electronics to biology directly at the single-molecule level.”
Olasagasti FA, Lieberman KR, Benner S, Akeson MA. Compositions, devices, systems, and methods for using a nanopore. U.S. Patent 9,481,908, filed February 27, 2014, issued November 1, 2016.