Past projects are rarely fully in the past. We might be convinced to take some of these up again if there is interest. Also these projects are interesting as the sources of much of our expertise.
Detection of magnet beads via flow NMR
While working at ABQMR, collaborators at UNM and Sandia got us interested in the use of microcoil NMR to detect the presence of magnetic particles in sample fluids. Early stages of this work were presented at the 8th ICMRM in Utsunomiya, Japan. This IP eventually formed part of the basis for founding nanoMR , a bio-tech startup here in Albuquerque.
The main focus of the work at nanoMR was to detect magnetically labeled bacteria and other pathogens in blood samples that were pumped through the NMR microcoil detector. As part of this work, we found we could reliably detect the passage of single micron-scale beads and even characterize the magnetic moment distribution of a population of beads. The nanoMR NMR device prototypes used disposable NMR probes that non-the-less achieved 25 ppb resolution in routine use. Unfortunately for the NMR group, it turned out to be more effective to use PCR to detect the pathogens, rather than NMR.
nanoMR has since merged with DNA Electronics Ltd. (UK) and moved to San Diego.
Ultracompact MRI
Also while at ABQMR, we had an NIH funded collaboration with Judy Thorn (Knox College) and Rebecca Harltley (UNM) to develop a very small MRI device for monitoring the development of Xenopus (frog) embryos. Xenopus is the traditional workhorse of developmental biology and remains relevant because you and I went through very similar stages when we were very, very young. The xenopus embryo is opaque, so researchers don't have optimal tools for observing interior events during growth. Very high field MRI has been shown to be useful, but it is too expensive for practial use in this field. We attempted to build a cost effective MRI unit that could produce useful biological information.
A full MRI device was constructed from the ground up, including the software needed to acquire and process spin echo and gradient echo images. A "large" 1.5 mm coil accommodated the embryo though many cell divisions, which were slowed by operating the system at 15-18 °ree C. A simple user interface allowed non-MRI experts to run the machine without support. Changes in early stage development and during gastrulation were very apparent on the resulting images, which were acquired continuously every 20 minutes or so.
This work was presented at Xenopus 2012.
Although the MRI worked quite well, the comparatively low 1.7 Tesla field made it difficult to generate adequate signal to noise, and the low field eliminated the chance to use fat-water selectivity to enhance the tissue constrast, which had been important to the earlier high-field studies. In the end, biologists did not find the new form of imaging to be helpful enough to put to routine use.
As an imager of small phantoms, such as tubes containing various liquids, the imager works extremely well, so we remain hopeful that the device can find an application some day.
MRT Compact Imager console software
Many years ago, while at New Mexico Resonance, my main project was developing the user interface code for the MRTechnology (Japan) Compact Imaging system. This work was with Shin Utsuzawa, who focussed his efforts on the machine control side of the software project. Altogther, somewhere in the neighborhodd of 20,000 lines of code were developed.
This work was my introduction to object oriented programming and windows programming, topics that continue to hold a morbid interest.
CE-NMR
While at ABQMR, I was contacted by Joanna Diekmann, a PhD student from Hannover, for help in completing her project to combine miniaturized capillary electrophoresis and microcoil NMR. We succeeded in building the device, now sited in Germany.
Our recent advances in methods for achieving much higher resolution in magnets of the size used in the CE-NMR project, so I suspect that much nicer data would be possible these days.
Nanoviscometer
Natalie Adolphi, UNM, has a recently patented idea for using magnetic particles for measuring viscosity at the microscopic scale. The basic steps are to add particles to the fluid to be measured, orient the particles' magnetic moments using a pulse of magnetic field, and then monitor the randomizing magnetic moments after the polarizing field is turned off. The original proof of principle was achieved using a SQUID detector system.
We have built a simple but working prototype using a much more cost-effective flux-gate detector to prove that a commercially practical device could be developed. What remains to complete the project is to develop the appropriate magnetic particles. We would need a collaborator to add this expertise.
