title: Assessment of analytical methods to determine pyrethroids content of bednets.
abstract: To present and evaluate simple, cost-effective tests to determine the amount of insecticide on treated materials.
  
  
  
  We developed and evaluated a competitive immunoassay on two different platforms: a label-free impedimetric biosensor (EIS biosensor) and a lateral flow. Both approaches were validated by gas chromatography (GC) and ELISA, gold standards for analytical methods and immunoassays, respectively. Finally, commercially available pyrethroid-treated ITN samples were analysed. Different extraction methods were evaluated.
  
  
  
  Insecticide extraction by direct infusion of the ITN samples with dichloromethane and dioxane showed recovery efficiencies around 100% for insecticide-coated bednets, and >70% for insecticide-incorporated bednets. These results were comparable to those obtained with standard sonication methods. The competitive immunoassay characterisation with ELISA presented a dynamic range between 12 nm and 1.5 μm (coefficient of variation (CV) below 5%), with an IC50at 138 nm, and a limit of detection (LOD) of 3.2 nm. EIS biosensor had a linear range between 1.7 nm and 61 nm (CV around 14%), with an IC50at 10.4 nm, and a LOD of 0.6 nm. Finally, the lateral flow approach showed a dynamic range between 150 nm and 1.5 μm, an IC50at 505 nm and a LOD of 67 nm.
  
  
  
  ELISA can replace chromatography as an accurate laboratory technique to determine insecticide concentration in bednets. The lateral flow approach developed can be used to estimate ITN insecticide concentration in the field. This new technology, coupled to the new extraction methods, should provide reliable guidelines for ITN use and replacement in the field.
authors.affiliation: ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Castellarnau
authors.affiliation: Nanobiotechnology for Diagnostics, Institute for Advanced Chemistry of Catalonia of the Spanish Council for Scientific Research, Barcelona, Spain.|CIBER de Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Ramón-Azcón
authors.affiliation: Institute of Environmental Assessment and Water Research, Barcelona, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Gonzalez-Quinteiro
authors.affiliation: Institute of Environmental Assessment and Water Research, Barcelona, Spain.
authors.forename: Jordi F
authors.initials: JF
authors.lastname: López
authors.affiliation: Institute of Environmental Assessment and Water Research, Barcelona, Spain.
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.affiliation: Nanobiotechnology for Diagnostics, Institute for Advanced Chemistry of Catalonia of the Spanish Council for Scientific Research, Barcelona, Spain.|CIBER de Bioingeniería, Biomateriales y Nanomedicina, Barcelona, Spain.
authors.forename: María-Pilar
authors.initials: MP
authors.lastname: Marco
authors.affiliation: ISGlobal, Centre for Research in Environmental Epidemiology (CREAL), Universitat Pompeu Fabra (UPF), CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.
authors.forename: Mark
authors.initials: M
authors.lastname: Nieuwenhuijsen
authors.affiliation: ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Picado
mesh_terms: D002849:Chromatography, Gas; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D057148:Insecticide-Treated Bednets; D007306:Insecticides / Q000032:analysis*; D009032:Mosquito Control / Q000379:methods; D011722:Pyrethrins / Q000032:analysis*
chemical_list: D007306:Insecticides; D011722:Pyrethrins
keywords: 
  MII
  ; biocapteur; biosensor; chromatographie; chromatography; cromatografía; cuantificación de insecticida; extracción de insecticida; extraction des insecticides; immunoassay; immunoessai; inmunoensayo; insecticide extraction; insecticide quantification; insecticide treated nets; mosquitera impregnada; quantification des insecticides