Flexible Specific Determination of Glucose in Solution, Blood Serum, and Sweat Using a Terahertz Hydrogel‐Functionalized Metamaterial

Abstract

Terahertz metamaterials have shown promises in biomolecules detection, however, aqueous solvents such as blood serum strongly absorb the terahertz waves, interfering with the detection. To avoid such interference, an ultrathin, flexible, biogel‐based metamaterial that can specifically detect the transmission of terahertz waves through biomolecules in aqueous solution is proposed and demonstrated. The glucose in water can be detected with a sensitivity of 0.0446 dL mg−1 and a detection limit of 1.64 mg dL−1, as well as glucose in human serum. The metamaterial that detects glucose in human sweat is part of a wearable device. The biosensor functions well for more than 100 detection cycles. The results suggest a strategy for real‐time detection of glucose and potentially other biomolecules.

Near-Field Terahertz Morphological Reconstruction Nanoscopy for Subsurface Imaging of Protein Layers

“…Terahertz (THz) waves typically refer to the electromagnetic radiation spanning a frequency range of 0.1–10 THz. − Due to their broadband, nondestructive, label-free, and biosensitive features, − THz techniques have found increasing imaging applications in diverse fields including biomedicine and materials science. − However, the spatial resolution of conventional far-field-based THz techniques is restricted by the wavelength, unable to exceed the Rayleigh diffraction limit . Recently, the development of THz scattering-type scanning near-field optical microscopy (THz s-SNOM) breaks the Rayleigh diffraction limit and enables a nanometer spatial resolution. − A THz s-SNOM system integrates a THz spectroscopy system with a tapping-mode AFM and has been applied to nanoscopic imaging of various functional structures such as InAs nanowire, graphene layers, Bi 2 Se 3 layers, and gold structures .…”