title: Biosensor based on hydrogel optical waveguide spectroscopy for the detection of 17β-estradiol.
abstract: Rapid detection of hormones at sub-ng/ml concentrations is of tremendous importance for diagnostic purposes, quality control, and environmental monitoring. In this respect, we report a novel label-free biosensor based on hydrogel optical waveguide spectroscopy (HOWS) for the sensitive detection of 17β-estradiol (E2). This approach was implemented by using a thin hydrogel layer of a carboxylated poly(N-isoproprylacrylamide) (PNIPAAm) terpolymer that was attached to a metallic sensor surface in order to simultaneously serve as a binding matrix and an optical waveguide. Refractive index changes that are accompanied with the specific capture of biomolecules from an aqueous sample on the sensor surface were probed by resonantly excited hydrogel optical waveguide modes. To optically excite and interrogate these waves, an optical setup based on Kretschmann configuration of attenuated total reflection (ATR) method that is compatible with surface plasmon resonance (SPR) was used. We demonstrate that HOWS offers a higher binding capacity, good anti-fouling properties, improved figure of merit, and E2 detection limit of 50 pg/ml which is seven times better than that obtained by a regular surface plasmon resonance (SPR) biosensor.
authors.affiliation: Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Beijing 100081, China.
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Anca
authors.initials: A
authors.lastname: Mateescu
authors.forename: Khulan
authors.initials: K
authors.lastname: Sergelen
authors.forename: Asmorom
authors.initials: A
authors.lastname: Kibrom
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jonas
authors.forename: Tianxin
authors.initials: T
authors.lastname: Wei
authors.forename: Jakub
authors.initials: J
authors.lastname: Dostalek
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D000180:Acrylic Resins; D000911:Antibodies, Monoclonal / Q000276:immunology; D015374:Biosensing Techniques; D004958:Estradiol / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D020100:Hydrogels; D007118:Immunoassay; D055620:Optical Phenomena; D011108:Polymers / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000276:immunology; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D000911:Antibodies, Monoclonal; D020100:Hydrogels; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D012710:Serum Albumin, Bovine; D004958:Estradiol