title: High-frequency phase shift measurement greatly enhances the sensitivity of QCM immunosensors.
abstract: In spite of being widely used for in liquid biosensing applications, sensitivity improvement of conventional (5-20MHz) quartz crystal microbalance (QCM) sensors remains an unsolved challenging task. With the help of a new electronic characterization approach based on phase change measurements at a constant fixed frequency, a highly sensitive and versatile high fundamental frequency (HFF) QCM immunosensor has successfully been developed and tested for its use in pesticide (carbaryl and thiabendazole) analysis. The analytical performance of several immunosensors was compared in competitive immunoassays taking carbaryl insecticide as the model analyte. The highest sensitivity was exhibited by the 100MHz HFF-QCM carbaryl immunosensor. When results were compared with those reported for 9MHz QCM, analytical parameters clearly showed an improvement of one order of magnitude for sensitivity (estimated as the I50 value) and two orders of magnitude for the limit of detection (LOD): 30μgl(-1) vs 0.66μgL(-1)I50 value and 11μgL(-1) vs 0.14μgL(-1) LOD, for 9 and 100MHz, respectively. For the fungicide thiabendazole, I50 value was roughly the same as that previously reported for SPR under the same biochemical conditions, whereas LOD improved by a factor of 2. The analytical performance achieved by high frequency QCM immunosensors surpassed those of conventional QCM and SPR, closely approaching the most sensitive ELISAs. The developed 100MHz QCM immunosensor strongly improves sensitivity in biosensing, and therefore can be considered as a very promising new analytical tool for in liquid applications where highly sensitive detection is required.
authors.affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, Edificio 8B-N, 46022 Valencia, Spain; Advanced Wave Sensors S.L. Valencia, Spain. Electronic address: cmarch@ginmuno.i3bh.es.
authors.forename: Carmen
authors.initials: C
authors.lastname: March
authors.affiliation: Advanced Wave Sensors S.L. Valencia, Spain; Grupo de Fenómenos Ondulatorios (GFO), Universitat Politècnica de València, Camino de Vera s/n, Edificio 7F, 46022 Valencia, Spain.
authors.forename: José V
authors.initials: JV
authors.lastname: García
authors.affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, Edificio 8B-N, 46022 Valencia, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Sánchez
authors.affiliation: Advanced Wave Sensors S.L. Valencia, Spain; Grupo de Fenómenos Ondulatorios (GFO), Universitat Politècnica de València, Camino de Vera s/n, Edificio 7F, 46022 Valencia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Arnau
authors.affiliation: Advanced Wave Sensors S.L. Valencia, Spain; Grupo de Fenómenos Ondulatorios (GFO), Universitat Politècnica de València, Camino de Vera s/n, Edificio 7F, 46022 Valencia, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Jiménez
authors.affiliation: Advanced Wave Sensors S.L. Valencia, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: García
authors.affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, Edificio 8B-N, 46022 Valencia, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Manclús
authors.affiliation: Instituto Interuniversitario de Investigación en Bioingeniería y Tecnología Orientada al Ser Humano (I3BH), Universitat Politècnica de València, Camino de Vera s/n, Edificio 8B-N, 46022 Valencia, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Montoya
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D000977:Antiparasitic Agents / Q000032:analysis; D015374:Biosensing Techniques / Q000295:instrumentation*; D012721:Carbaryl / Q000032:analysis*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D057230:Limit of Detection; D010575:Pesticides / Q000032:analysis*; D058525:Quartz Crystal Microbalance Techniques / Q000295:instrumentation*; D013827:Thiabendazole / Q000032:analysis
chemical_list: D000911:Antibodies, Monoclonal; D000977:Antiparasitic Agents; D010575:Pesticides; D013827:Thiabendazole; D012721:Carbaryl
keywords: HFF QCM; High fundamental frequency; Immunosensor; Sensitivity enhancement