In this project described in this revised proposal, a selective wirelessly-adjustable multiple-frequency probe (SWAMP) will be developed for non-invasive measurement of nuclear magnetic resonance (NMR) in vivo from a range of biologically important nuclei within implanted tissue constructs. This device will be instrumental in guiding the development of these tissue-engineered constructs by providing a method to monitor the viability and efficacy of these constructs in living subjects. But the same technology can be used to study a range of other significant biological systems, such as the spinal cord and other deep organ-systems, which require remote monitoring. Most importantly for our study, this device can non-invasively monitor the function of an implanted bioartificial-pancreas tissue construct. Therefore, the long-term objective of this project is to provide a clinical device that can be used in any magnet system to non-invasively examine the viability and function of a bioengineered tissue construct within a patient. The SWAMP system will use an NMR coil, implanted with the tissue construct, which is inductively coupled to an external coil. The development of this system will be accomplished by completing three specific aims: 1) Develop a microchip system to selectively tune an implanted NMR coil remotely to the frequency (nucleus) of interest and also develop an external-coil circuit, which will automatically impedance match the system. 2) Integrate these two components into the inductively coupled coil system and develop radio frequency pulse programs to automatically control the device. 3) Test the device performance by examining the functional status of a bioartificial pancreas tissue construct in gel phantoms during a longitudinal study of construct viability. This device is a major advance in NMR technology for monitoring implanted tissue or organs deep within the body. Current NMR implanted coil technology cannot be used to measure a full range of biologically important nuclei from implanted tissue without a severe loss of sensitivity for some nuclei. Therefore NMR measurements are not possible for this important range of nuclei without sacrificing significant biochemical information. The proposed SWAMP system overcomes this limitation through the innovative use of micro- fabrication technology to produce a single device that has optimum performance at all nuclei of interest and can be tuned remotely. Because of these significant performance improvements and ease of use, the SWAMP system can be used to obtain NMR data from a complete range of nuclei and provide critical information about the biochemical status of an implanted tissue construct.
Tissue constructs are a potential treatment of a range of diseases, such as diabetes using a bioartificial pancreas, which can replace the function of failed tissue, e.g. pancreas tissues. However artificial tissue constructs must be monitored to assure that they are functioning properly and to predict if they might fail, e.g. for diabetes, well in advance of changes in blood glucose levels. The proposed selective wirelessly-adjustable multiple-frequency probe for nuclear magnetic resonance can monitor an implanted tissue construct, such as a bioartificial pancreas, non-invasively by remotely selecting key nuclei to examine with optimum sensitivity.
