title: Glucose monitoring using a polymer brush modified polypropylene hollow fiber-based hydraulic flow sensor.
abstract: Tight regulation of blood glucose levels of diabetic patients requires durable and robust continuous glucose sensing schemes. This manuscript reports the fabrication of ultrathin, phenylboronic acid (PBA) functionalized polymer brushes that swell upon glucose binding and which were integrated as the sensing interface in a new polypropylene hollow fiber (PPHF)-based hydraulic flow glucose sensor prototype. The polymer brushes were prepared via surface-initiated atom transfer radical polymerization of sodium methacrylate followed by postpolymerization modification with 3-aminophenyl boronic acid. In a first series of experiments, the glucose-response of PBA-functionalized poly(methacrylic acid) (PMAA) brushes grafted from planar silicon surfaces was investigated by quartz crystal microbalance with dissipation (QCM-D) and atomic force microscopy (AFM) experiments. The QCM-D experiments revealed a more or less linear change of the frequency shift for glucose concentrations up to ∼10 mM and demonstrated that glucose binding was completely reversible for up to seven switching cycles. The AFM experiments indicated that glucose binding was accompanied by an increase in the film thickness of the PBA functionalized PMAA brushes. The PBA functionalized PMAA brushes were subsequently grafted from the surface of PPHF membranes. The hydraulic permeability of these porous fibers depends on the thickness and swelling of the PMAA brush coating. PBA functionalized brush-coated PPHFs showed a decrease in flux upon exposure to glucose, which is consistent with swelling of the brush coating. Because they avoid the use of enzymes and do not rely on an electrochemical transduction scheme, these PPHF-based hydraulic flow sensors could represent an interesting alternative class of continuous glucose sensors.
authors: Institut des Matériaux and Institut des Sciences et Ingénierie Chimiques, Laboratoire des Polymères, École Polytechnique Fédérale de Lausanne (EPFL) , Bâtiment MXD, Station 12, CH-1015 Lausanne, Switzerland.
authors: Nicolas
authors: N
authors: Fortin
authors: Harm-Anton
authors: HA
authors: Klok
mesh_terms: D001897:Boronic Acids / Q000737:chemistry; D055664:Electrochemical Techniques; D005947:Glucose / Q000032:analysis*; D018625:Microscopy, Atomic Force; D011109:Polymethacrylic Acids / Q000737:chemistry; D011126:Polypropylenes / Q000737:chemistry*; D016062:Porosity; D058525:Quartz Crystal Microbalance Techniques; D012825:Silicon / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D001897:Boronic Acids; D011109:Polymethacrylic Acids; D011126:Polypropylenes; C030613:polymethacrylic acid; C028592:3-aminobenzeneboronic acid; D005947:Glucose; D012825:Silicon
keywords: glucose sensor; hydraulic permeability; phenylboronic acid; polymer brushes; surface-initiated atom transfer radical polymerization