Publications by authors named "Mariia Dekaliuk"

Integrating isothermal nucleic acid amplification strategies into immunoassays can significantly decrease analytical limits of detection (LODs). On the other hand, an amplification step adds time, complication, reagents, and costs to the assay format. To evaluate the pros and cons in the context of heterogeneous multistep immunoassays, we quantified prostate-specific antigen (PSA) with and without rolling circle amplification (RCA).

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Multipollutant approach is a breakthrough in up-to-date environmental quality and health risk estimation. Both mercury and carbonaceous air particulate are hazardous neurotoxicants. Here, the ability of carbonaceous air particulate simulants, i.

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The quantification of very low concentrations of circulating tumor DNA (ctDNA) biomarkers from liquid biopsies has become an important requirement for clinical diagnostics and personalized medicine. In particular, the simultaneous detection of wild-type (WT) dsDNA and their cancer-related counterparts presenting single-point mutations with simple, sensitive, specific, and reproducible technologies is paramount for ctDNA assays in clinical practice. Here, we present the development and evaluation of an amplified dsDNA assay based on a combination of isothermal rolling circle amplification (RCA) and time-gated Förster resonance energy transfer (TG-FRET) between a Tb donor and two dye (Cy3.

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The unexpected discovery of the photoluminescence of carbon nanoparticles attracted the attention of many researchers and resulted in their use in a variety of applications. However, the origin of their emission is still obscure, and the majority of the discussions on the subject focus on their molecular and/or excitonic emissive states. We performed cryogenic studies down to 10 K and did not observe any signatures of suppressed molecular relaxation - the spectra remained broad, showing large unaltered Stokes shifts and temperature-independent emission intensities and lifetimes below 80 K with a weak dependence above this value.

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Carbon nanoparticles that may be potent air pollutants with adverse effects on human health often contain heteroatoms including sulfur. In order to study in detail their effects on different physiological and biochemical processes, artificially produced carbon dots (CDs) with well-controlled composition that allows fluorescence detection may be of great use. Having been prepared from different types of organic precursors, CDs expose different atoms at their surface suggesting a broad variation of functional groups.

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At present, there is no consensus understanding on the origin of photoluminescence of carbon nanoparticles, particularly the so-called carbon dots. Providing comparative analysis of spectroscopic studies in solution and on a single-molecular level, we demonstrate that these particles behave collectively as fixed single dipoles and probably are the quantum emitter entities. Their spectral and lifetime heterogeneity in solutions is explained by variation of the local chemical environment within and around luminescence centers.

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Success in super-resolution imaging relies on a proper choice of fluorescent probes. Here, we suggest novel easily produced and biocompatible nanoparticles-carbon nanodots-for super-resolution optical fluctuation bioimaging (SOFI). The particles revealed an intrinsic dual-color fluorescence, which corresponds to two subpopulations of particles of different electric charges.

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Apoptosis is a genetically encoded cell death program that involves different processes occurring on molecular and sub-cellular levels. Here we report on its new features--the increased accumulation of fluorescent carbon nanoparticles (CDots) in cells and their changed distribution within cell interior, which can witness on altered mechanisms of their translocation through the membrane. The comparative studies of living (intact) and apoptotic cells were provided with two cell lines (HeLa, Vero) using two types of fluorescent nanoparticles ("violet" and "blue" CDots).

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Carbon dots (C-dots), a recently discovered class of fluorescent nano-sized particles with pure carbon core, have great bioanalytical potential. Neuroactive properties of fluorescent C-dots obtained from β-alanine by microwave heating were assessed based on the analysis of their effects on the key characteristics of GABA- and glutamatergic neurotransmission in isolated rat brain nerve terminals. It was found that C-dots (40-800 μg/ml) in dose-dependent manner: (1) decreased exocytotic release of [(3)H]GABA and L-[(14)C]glutamate; (2) reduced acidification of synaptic vesicles; (3) attenuated the initial velocity of Na(+)-dependent transporter-mediated uptake of [(3)H]GABA and L-[(14)C]glutamate; (4) increased the ambient level of the neurotransmitters, nevertheless (5) did not change significantly the potential of the plasma membrane of nerve terminals.

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Inorganic carbon nanomaterials, also called carbon nanodots, exhibit a strong photoluminescence with unusual properties and, thus, have been the focus of intense research. Nonetheless, the origin of their photoluminescence is still unclear and the subject of scientific debates. Here, we present a single particle comprehensive study of carbon nanodot photoluminescence, which combines emission and lifetime spectroscopy, defocused emission dipole imaging, azimuthally polarized excitation dipole scanning, nanocavity-based quantum yield measurements, high resolution transmission electron microscopy, and atomic force microscopy.

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Despite many efforts, the mechanisms of light absorption and emission of small fluorescent carbon nanoparticles (C-dots) are still unresolved and are a subject of active discussion. In this work we address the question as to whether the fluorescence is a collective property of these nanoparticles or they are composed of assembled individual emitters. Selecting three types of C-dots with "violet", "blue" and "green" emissions and performing a detailed study of fluorescence intensity, lifetime and time-resolved anisotropy as a function of excitation and emission wavelengths together with the effect of viscogen and dynamic fluorescence quencher, we demonstrate that the C-dots represent assemblies of surface-exposed fluorophores.

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Small brightly fluorescent carbon nanoparticles have emerged as a new class of materials important for sensing and imaging applications. We analyze comparatively the properties of nanodiamonds, graphene and graphene oxide 'dots', of modified carbon nanotubes and of diverse carbon nanoparticles known as 'C-dots' obtained by different methods. The mechanisms of their light absorption and luminescence emission are still unresolved and the arguments are presented for their common origin.

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