title: Microalgae fiber optic biosensors for herbicide monitoring using sol-gel technology.
abstract: Three microalgal species (Dictyosphaerium chlorelloides (D.c.), Scenedesmus intermedius (S.i.) and Scenedesmus sp. (S.s.)) were encapsulated in silicate sol-gel matrices and the increase in the amount of chlorophyll fluorescence signal was used to quantify simazine. Influence of several parameters on the preparation of the sensing layers has been evaluated: effect of pH on sol-gel gelation time; effect of algae density on sensor response; influence of glycerol (%) on the membrane stability. Long term stability was also tested and the fluorescence signal from biosensors remained stable for at least 3 weeks. D.c. biosensor presented the lowest detection limits for simazine (3.6 microg L(-1)) and the broadest dynamic calibration range (19-860 microg L(-1)) with IC(50) 125+/-14 microg L(-1). Biosensor was validated by HPLC with UV/DAD detection. The biosensor showed response to those herbicides that inhibit the photosynthesis at photosystem II (triazines: simazine, atrazine, propazine, terbuthylazine; urea based herbicides: linuron). However, no significant increases of fluorescence response was obtained for similar concentrations of 2,4-D (hormonal herbicide) or Cu(II). The combined use of two biosensors that use two different genotypes, sensitive and resistant to simazine, jointly allowed improving microalgae biosensor specificity.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Peña-Vázquez
authors.forename: Emilia
authors.initials: E
authors.lastname: Maneiro
authors.forename: Concepción
authors.initials: C
authors.lastname: Pérez-Conde
authors.forename: Maria Cruz
authors.initials: MC
authors.lastname: Moreno-Bondi
authors.forename: Eduardo
authors.initials: E
authors.lastname: Costas
mesh_terms: D001681:Biological Assay / Q000295:instrumentation*; D015374:Biosensing Techniques / Q000295:instrumentation*; D001709:Biotechnology / Q000295:instrumentation; D004784:Environmental Monitoring / Q000295:instrumentation*; D056890:Eukaryota / Q000187:drug effects*; D005336:Fiber Optic Technology / Q000295:instrumentation*; D008163:Luminescent Measurements / Q000295:instrumentation*; D008904:Miniaturization; D012839:Simazine / Q000032:analysis* / Q000494:pharmacology*
chemical_list: D012839:Simazine