title: Continuous glucose monitoring by means of mid-infrared transmission laser spectroscopy in vitro.
abstract: The continuous surveillance of glucose concentration reduces short-term risks and long-term complications for people with diabetes mellitus, a disorder of glucose metabolism. As a first step towards the continuous monitoring of glucose, reagent-free transmission spectroscopy in the mid-infrared region has been carried out in vitro using a quantum cascade laser and an optical silver halide fiber. A 30 μm gap in the fiber allowed for transmission spectroscopy of aqueous glucose solutions at a wavelength of 9.69 μm, which is specific to a molecular vibration of glucose. A noise-equivalent concentration as low as 4 mg/dL was achieved at an average power of 1.8 mW and an integration time of 50 s. This is among the most precise of glucose measurements using mid-infrared spectroscopy. Even with the very low average laser power of 0.07 mW the sensitivity of previous results (using a fiber optical evanescent field analysis) has been improved upon by almost one order of magnitude. Finally, the impact of potentially interfering substances such as other carbohydrates was analyzed.
authors.affiliation: Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Vrančić
authors.forename: Anna
authors.initials: A
authors.lastname: Fomichova
authors.forename: Norbert
authors.initials: N
authors.lastname: Gretz
authors.forename: Carina
authors.initials: C
authors.lastname: Herrmann
authors.forename: Sabine
authors.initials: S
authors.lastname: Neudecker
authors.forename: Annemarie
authors.initials: A
authors.lastname: Pucci
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Petrich
mesh_terms: D001965:Bromides / Q000737:chemistry; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000378:metabolism; D005947:Glucose / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D007834:Lasers; D055100:Optical Fibers; D018030:Silver Compounds / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors
chemical_list: D001965:Bromides; D018030:Silver Compounds; D005947:Glucose; C037548:silver chloride; C047751:silver bromide