Layer-by-layer films containing peptides of the Cry1Ab16 toxin from Bacillus thuringiensis for potential biotechnological applications

PLACIDO ALEXANDRA; OLIVEIRA FARIAS EMANUEL A.; MARANI MARIELA M.; VASCONCELOS ADREANNE G.; MAFUD ANA C.; MASCARENHAS YVONNE P.; EIRAS CARLA; LEITE JOSÉ R. S. A.; DELERUE-MATOS MARÍA C.

MATERIALS SCIENCE & ENGINEERING. C, BIOMIMETIC MATERIALS, SENSORS AND SYSTEMS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 61 p. 832 - 841

0928-4931

Cry1Ab16 is a toxin of crystalline insecticidal proteins that has been widely used in genetically modified organisms(GMOs) to gain resistance to pests. For the first time, in this study, peptides derived fromthe immunogenicCry1Ab16 toxin (from Bacillus thuringiensis) were immobilized as layer-by-layer (LbL) films. Given the concernabout food and environmental safety, a peptide with immunogenic potential, PcL342?354C, was selected forcharacterization of the electrochemical, optical, and morphological properties. The results obtained by cyclicvoltammetry (CV) showed that the peptide have an irreversible oxidation process in electrolyte of 0.1 mol·L−1potassiumphosphate buffer (PBS) at pH7.2. Itwas also observed that the electrochemical response of the peptideis governed mainly by charge transfer. In an attempt to maximize the electrochemical signal of peptide, it wasintercalated with natural (agar, alginate and chitosan) or synthetic polymers (polyethylenimine (PEI) andpoly(sodium 4-styrenesulfonate (PSS)). The presence of synthetic polymers on the film increased the electrochemicalsignal of PcL342?354C up to 100 times. Images by Atomic Force Microscopy (AFM) showed that theimmobilized PcL342?354C formed self-assembled nanofibers with diameters ranging from 100 to 200 nm onthe polymeric film. By UV?Visible spectroscopy (UV?Vis) it was observed that the ITO/PEI/PSS/PcL342?354Cfilm grows linearly up to the fifth layer, thereafter tending to saturation. X-ray diffraction confirmed the presenceon the films of crystalline ITO and amorphous polypeptide phases. In general, the ITO/PEI/PSS/PcL342?354C filmcharacterization proved that this systemis an excellent candidate for applications in electrochemical sensors andother biotechnological applications for GMOs and environmental indicators.