232. MRI-Based Glucose Assay Using Magnetic Nanoparticle Sensors
Glucose sensors for NMR relaxometry and magnetic resonance imaging (MRI) can be used for direct measurement of glucose in turbid biological specimens. Here, we proposed a magnetic glucose sensor based on superparamagnetic iron oride (SPIO) nanoparticles conjugated to a mannopyranoside derivative and concanavalin A (ConA). The binding of mannopyranoside groups to SonA produced a nanoparticle cluster that was dissociated by competitive binding of glucose to ConA, resulting in changes in the transverse relaxation time (T2) in a glucose-dependent manner. The sensor gave rise to significant T2 changes in physiological glucose levels of 3-8 mM at a nanoparticle concentration of 0.5 nM. Significant T2 responses were observed within 6 min of 5 mM glucose detection. Sensor-based MRI by a benchtop 1 tesla scanner permitted a measurement of multiple samples within 8 min. These results demonstrate that the relaxometric glucose sensor could lead to high throughput diret assay of blood samples by using a compact MRI scanner for point-of-care testing.