Contactless Glucose Sensing at Sub-Micromole Level Using a Deep-Subwavelength Decimeter-Wave Plasmonic Resonator

Microwave resonance sensing has found a wide variety of applications and exhibits promising potentials in compact integrated sensors. However, its distinguishing ability to trace-amount targets remains challenging, which can be characterized by the effective wavelength and the quality factor (Q-factor). Here, a contactless sensing scheme for detecting sub-micromole glucose using a deep-subwavelength spoof localized surface plasmon (SLSP) resonator working at the decimeter-wave band is proposed. The SLSP resonator sustains a mixed-mode of an electric monopole and a magnetic dipole, compressing the electromagnetic mode into a diameter smaller than lambda(0)/41 (lambda(0) is the free-space wavelength) and achieving a measured Q-factor of 187. In experiments, contactless sensing has been realized using a polydimethylsiloxane (PDMS) microfluidic channel, which separates the resonator and the solution. The solution sample under test features an ultra-compact volume of 3.7 x 10(-8) lambda(3)(0), and a detection limit of 0.45 mu mol glucose is demonstrated. This work envisions the applications of spoof localized surface plasmons in the contactless and trace-amount biomedical sensing.

Automated summary

This paper proposes a contactless microwave resonance sensing scheme for detecting sub-micromole glucose using a deep-subwavelength spoof localized surface plasmon (SLSP) resonator. Experimental results show a detection limit of 0.45 μmol glucose.