ABSTRACT
Flavivirus detection in humans and mosquito reservoirs has been an important issue since it can cause a variety of illnesses and could represent a health problem in geographical zones where the vector is endemic. In this work, we designed and characterized a biosensor based on gold nanoparticles (AuNPs) and antibody 4G2 for the detection of dengue virus (DENV) in vitro, obtaining different conjugates (with different antibody concentrations). The AuNP-4G2 conjugates at concentrations of 1, 3, and 6 µg/mL presented an increase in the average hydrodynamic diameter compared to the naked AuNPs. Also, as part of the characterization, differences in the UV-Vis absorbance spectrum and electrophoretic migration were observed between the conjugated AuNPs (with BSA or antibody) and naked AuNPs. Additionally, we used this biosensor (AuNP-4G2 conjugate with 3 µg/mL antibody) in the assembly of a competitive lateral flow assay (LFA) for the development of an alternative test to detect the flavivirus envelope protein in isolated DENV samples as a future tool for dengue detection (and other flaviviruses) in the mosquito vector (Aedesaegypti) for the identification of epidemic risk regions. Functionality tests were performed using Dengue virus 2 isolated solution (TCID50/mL = 4.58 × 103) as a positive sample and PBS buffer as a negative control. The results showed that it is possible to detect Dengue virus in vitro with this gold nanoparticle-based lateral flow assay with an estimated detection limit of 5.12 × 102 PFU. We suggest that this biosensor could be used as an additional detection tool by coupling it to different point-of-care tests (POCT) for the easy detection of other flaviviruses.
Subject(s)
Biosensing Techniques , Dengue Virus , Metal Nanoparticles , Animals , Biosensing Techniques/methods , Gold , Humans , Immunoassay/methodsABSTRACT
An HPLC-UV/FLD method for simultaneous detection of ten antibiotics in surface waters was developed. Antibiotics were extracted from water using solid phase extraction. An Atlantis T3 column was used with acetonitrile and 0.05% trifluoroacetic acid as a mobile phase for separation, with a total running time of 45 min. Signal detection was performed at 280 nm; fluoroquinolones were additionally quantified by fluorescence detection. Validation parameters such as linearity, recovery and precision were evaluated. The limits of detection (LOD) in river waters were in the range 0.1-1.3 µg/L for antibiotics detected by UV, and 0.039 and 0.073 µg/Lfor fluoroquinolones detected by FLD. LOD are sufficiently low to consider this method as a first alternative for HPLC-MS methods that will allow alerting for the presence of antibiotics in surface waters. This screening method is rapid, sensitive, reproducible and economical.
