A new sensor technology developed by a team of researchers at the University of New Mexico can detect and identify trace molecules in samples at the picoliter level (one trillionth of a liter). The sensor optically converts the magnetic field produced by the molecules into red fluorescence to detect the presence of the molecule and, for the first time, identify its composition in two dimensions. The technology was developed by UNM Assistant Professor Victor Acosta from the Department of Physics & Astronomy and a team of researchers from the UNM Center for High Technology Materials, the University of California at Berkeley, Sandia, startup ODMR, and company NuevoMR LLC. This new, alternative NMR detection method achieved an order of magnitude improvement in spectral resolution over previous diamond NMR studies and holds promise for microfluidic NMR applications for mass-limited chemical analysis and single-cell biology.
Dr. Acosta and his quantum nanophotonics and biosensing team at the Center for High Technology Materials conduct research in the area where condensed-matter physics, quantum optics, and biomedical imaging intersect. The researchers specialize in using color centers in diamond as quantum sensors to study nanoscale magnetic phenomena in physical, chemical, and biological systems, and are interested in developing nanophotonic surfaces for applications ranging from few-photon optical logic to virtual reality.
Dr. Acosta’s related technologies, “Magnetic Resonance Spectrometer,” and “Optical Nuclear Magnetic Resonance Microscope and Measurement Methods,” have pending patent applications.
The magnetic-resonance spectrometer detects sub-nanoliter volumes of liquid, gas, and thin-film samples over a wide range of ambient temperatures. The sensor increases the total contact area with the sample, causing a boost in NMR signal and reduction in acquisition time. This allows for sensitive detection of subnanoliter volumes of trace sample under a wide variety of environmental conditions. The sensor can be used in low magnetic fields to detect nuclear quadrupole resonance (NQR), making it possible to detect extremely small trace quantities of analytes (e.g. nanograms of powder). The technology has applications for forensic sciences as an alternative to Raman, mass spectrometry, or traditional NMR/NQR techniques.
The optical nuclear magnetic resonance microscope is non-invasive and operates with a high level of sensitivity. Unlike currently available technologies, this microscope’s special sensor requires smaller magnetic fields while providing improved spectral resolution and a detection threshold to less than 1010 spins. This reduces manufacturing costs and allows for a non-invasive NMR technique with a higher level of sensitivity that can be applied to single-cell metabolomics research. With further improvements, this technology could enable a wide variety of applications in biochemical research where NMR utility is currently limited.
To read more about the quantum sensor technology see Mary Beth King’s August 8 article, “UNM team develops quantum sensor technology,” from UNM Newsroom, below. To read the published paper, go to https://advances.sciencemag.org/content/5/7/eaaw7895.
UNM team develops quantum sensor technology
A team of researchers from The University of New Mexico and its Center for High Technology Materials (CHTM) recently published a new paper in the journal Science Advances detailing their work in developing a quantum sensor for determining the chemical composition of trace quantities of samples.
The paper is titled Two-dimensional nuclear magnetic resonance spectroscopy with a microfluidic diamond quantum sensor. The technology could have a big impact on numerous scientific fields, ranging from analytic chemistry to single-cell biology.
The team is led by Victor Acosta, assistant professor in the Department of Physics & Astronomy and CHTM, in conjunction with Andrey Jarmola, University of California, Berkeley Department of Physics, and CEO of ODMR Technologies Inc. The co-first authors are graduate student Janis Smits, who is affiliated with UNM and the University of Latvia Laser Center, and CHTM post-doc Joshua Damron.
The team also includes postdoc Ilja Fescenko, grad students Nazanin Mosavian and Nathaniel Ristoff, and research assistant professor Abdelghani Laraoui, all of CHTM and the Department of Physics & Astronomy; Truman Fellow Pauli Kehayias, CHTM and Sandia National Laboratories; and Andrew F. McDowell, NuevoMR LLC.
Acosta compared the nuclear magnetic resonance (NMR) technology to MRI machines used to scan a whole human body. A key difference is the diamond quantum sensor NMR technology his team is developing can detect and identify tiny, trace quantities of molecules in fluids (or even individual cells) as small as one picoliter – one-trillionth of a liter.
“NMR is like a single pixel in an MRI, except it gives more quantitative information about the molecules that are present,” he observed.
The sensor is comprised of nitrogen-vacancy defects in diamond, a quantum system that can be used to optically detect the magnetic fields produced by the nuclei in molecules, Acosta explained. Different molecules have specific magnetic resonance properties that are converted by the sensor into different fluorescent intensities of red, which can be detected and then identified by the device.
As they report in their paper, the researchers integrated a diamond quantum sensor into a microfluidic platform that shuttled fluids between a strong permanent magnet – “like refrigerator magnets,” he explained – and a carefully-controlled electromagnet. They were able to register NMR spectra of picoliter-volumes of fluids with a higher sensitivity and spectral resolution than was possible in previous work. This allowed them to perform, for the first time with diamond quantum sensors, two-dimensional NMR spectroscopy, an important technique for quantifying the molecular composition of complex bodily fluids and identifying the structure of proteins.
NMR spectroscopy is of great interest to numerous researchers and industries. The development of new NMR methods has garnered six Nobel prizes in the fields of physics, chemistry, and medicine, Acosta said, adding “That’s how important it is.”
The team’s diamond quantum sensor technology has already attracted commercial interest. Jarmola’s start-up is working towards commercializing the technology. Uses for NMR include environmental safety, public security and defense, petroleum exploration, disease detection, and oncology medicine.
*** This study was funded by a NIH National Institute of General Medical Sciences award 1R41GM130239-01 and a Beckman Young Investigator award. Smits received support from the Latvian Government (A5-AZ27, Y9-B013).