ABSTRACT
Magnetic separation based on biologically-modified magnetic particles is a preconcentration procedure commonly integrated in magneto actuated platforms for the detection of a huge range of targets. However, the main drawback of this material is the low stability and high cost. In this work, a novel hybrid molecularly-imprinted polymer with magnetic properties is presented with affinity towards biotin and biotinylated biomolecules. During the synthesis of the magneto core-shell particles, biotin was used as a template. The characterization of this material by microscopy techniques including SEM, TEM and confocal microscopy is presented. The application of the magnetic-MIPs for the detection of biotin and biotinylated DNA in magneto-actuated platforms is also described for the first time. The magnetic-MIP showed a significant immobilization capacity of biotinylated molecules, giving rise to a cheaper and a robust method (it is not required to be stored at 4°C) with high binding capacity for the separation and purification under magnetic actuation of a wide range of biotinylated molecules, and their downstream application including determination of their specific targets.
Subject(s)
Biotin/isolation & purification , Magnets/chemistry , Molecular Imprinting/methods , Polymers/chemistry , Biotin/chemistry , Biotinylation , DNA, Bacterial/chemistry , DNA, Bacterial/isolation & purification , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Humans , Immunoassay/methods , MagneticsABSTRACT
A chitosan-modified carbon fiber electrode (CFE) for dengue virus envelope protein (DENV) was developed. Antibodies against DENV were covalently immobilized on the chitosan (CHIT) matrix after activation with sodium periodate. Cyclic voltammetries and scanning electron microscopies analysis were performed to monitor steps involved in the CFE surface modification. Amperometric response of the competitive immunoassays was generated by hydrogen peroxide reaction with the peroxidase conjugated to DENV and 2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) as mediator. The immunosensor showed a lower limit of detection for DENV (0.94 ng mL(-1)) than previously described and a linear range from 1.0 to 175 ng mL(-1), in concentration levels clinically relevant for dengue virus diagnosis. The intra- and inter-assay were respectively 5.8% and 3.6%. The unique and simple design of this immunoassay format provides an economical alternative for the manufacture of other sensitive sensors.