When fluorophores attach to nanostructured films of intrinsically conducting polymers (ICPs), a quenching of their fluorescence may occur. We have exploited these characteristics for the development of polymeric films that can be used in a simple and efficient molecular diagnosis protocol based on the selective detection of nucleic acids. Our procedure rests on the fact that the fluorescence of 6-carboxyfluorescein-labeled single-stranded DNA (FAM-ssDNA) probes is quenched upon their immobilization on nanostructured ICP - polypyrrole (PPY) and polyaniline (PANI) - films deposited on polyethylene terephthalate (PET) substrates. Hybridization occurs whenever a sample with the complementary sequence is brought in contact with the immobilized probe, with the newly formed ds-DNA chains detaching from the flexible polymeric film and causing the restoration of the fluorescence. This sensing system exhibits a low background signal that depends on both the thickness and hydrophobicity of the films. As a model system, we used a FAM-ssDNA probe specific for the Leishmania infantum parasite. The results confirm this procedure as a simple, fast and highly sensitive scheme for the recognition of the target DNA, with a detection limit of the 1.1 nM and 1.3 nM for the PPY/PET and PANI/PET films, respectively. In addition, this biosensor has excellent stability and exhibits a good and reproducible performance even when used for the direct detection of ssDNA in relatively complex biological samples.
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http://dx.doi.org/10.1016/j.aca.2018.10.010 | DOI Listing |
Langmuir
January 2025
Chemistry and Structure of novel Materials, University of Siegen, Paul-Bonatz Strasse 9-11, 57068 Siegen, Germany.
The surface charge of metal oxides is an important property that significantly contributes to a wide range of phenomena, including adsorption, catalysis, and material science. The surface charge can be predicted by determining the isoelectric point (IEP) of a material and the pH of a solution. Although there have been several studies of the IEP of metal oxide (nano)particles, only a few have reported the IEP of metal oxide films.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Mechanical Engineering, University of California at Riverside, Riverside, California 92521, United States.
Sensing light's polarization and wavefront direction enables surface curvature assessment, material identification, shadow differentiation, and improved image quality in turbid environments. Traditional polarization cameras utilize multiple sensor measurements per pixel and polarization-filtering optics, which result in reduced image resolution. We propose a nanophotonic pipeline that enables compressive sensing and reduces the sampling requirements with a low-refractive-index, self-assembled optical encoder.
View Article and Find Full Text PDFJ Food Sci
January 2025
Nutrition Research Center, Department of Food Science and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
Alternatives to nonbiodegradable synthetic plastics for food packaging include films made from biopolymers that are nontoxic and environment-friendly. In this study, carnauba wax (CW) and nitrogen-doped graphene quantum dots (NG) as functional additives were utilized in the production of pectin/gelatin (PG) film. NG was synthesized through the microwave method, using acetic acid as the carbon source, giving size, and zeta potential of 1.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Hebei Lansheng Bio-Tech Co, Ltd, Shijiazhuang, 052263, P. R. China.
A novel fluorescence sensing nanoplatform (CDs/AuNCs@ZIF-8) encapsulating carbon dots (CDs) and gold nanoclusters (AuNCs) within a zeolitic imidazolate framework-8 (ZIF-8) was developed for ratiometric detection of formaldehyde (FA) in the medium of hydroxylamine hydrochloride (NHOH·HCl). The nanoplatform exhibited pink fluorescence due to the aggregation-induced emission (AIE) effect of AuNCs and the internal filtration effect (IFE) between AuNCs and CDs. Upon reaction between NHOH·HCl and FA, a Schiff base formed via aldehyde-diamine condensation, releasing hydrochloric acid.
View Article and Find Full Text PDFACS Omega
January 2025
Centro de Investigación en Materiales Avanzados, S.C. (CIMAV Subsede Monterrey), Alianza Norte 202, Parque de Investigación e Innovación Tecnológica, C.P. 66628 Apodaca, Nuevo León, Mexico.
Thermal atomic layer deposition (TALD) and plasma atomic layer deposition (PALD) were used for producing thin NiO films from nickel(II) acetylacetonate Ni(acac), employing different oxidizing agents (deionized water HO, ozone O, and molecular oxygen O). The films were deposited at 300 °C (TALD) and 220 °C (PALD) over glass substrates; their physical and chemical properties were considerably influenced by the choice of oxidizing agents. In particular, ALD(HO) samples had a low growth per cycle (GPC) and a high concentration of defects.
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