In this paper, we report on a wireless glucose sensor based on a magnetically functionalized hydrogel (ferrogel) patterned on top of a planar inductor, Figure 1(a). The ferrogel is prepared by physically embedding magnetic nanoparticles in the hydrogel network. The volume change of the ferrogel in response to glucose concentrations modulates the self-resonant frequency of the coil, a lower permeability/inductance in the shrunken state and a higher permeability/inductance in the swollen state. The inductance change can be remotely monitored by measuring the resonant frequency of the coil. A 3-(acrylamido)phenylboronic (3APBA) acid-based polyacrylamide hydrogel was used as the sensing material. The hydrogel shrinks in the 0-20 mM glucose concentration range due to a 2:1 crosslinking complex formed between 3APBA and glucose. This glucose induced crosslinking complex adds to the total crosslink concentration inside the hydrogel leading to the shrinkage of the hydrogel matrix and commensurate increase in resonant frequency. The crosslink formation is reversible and dependent on the glucose concentration in the environment. Figure 1(b) shows the kinetics of resonant frequency in response to different glucose concentrations. The frequency increases by 70 kHz when glucose concentration is varied from 5 to 10 mM. The sensor has a sensitivity of 12.61 kHz/mM, a resolution of 0.4 mM, and a response time of 10 min.

Wireless glucose sensor utilizing magnetic nanoparticles embedded hydrogel

249th National Meeting (2015)

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