An NGQD Based Diagnostic Tool for Pancreatic Cancer

Background: Pancreatic cancer remains difficult to detect at early stages which contributes to a poor five-yearsurvival rate. Therefore, early detection approaches based on novel technologies should be explored to address this critical health issue. Nanomaterials have recently emerged as frontrunners for diagnostic applications due to their small size in the 1-100 nm range, which facilitates one-on-one interactions with a variety of biomolecules like oligonucleotides and makes them suitable for a plethora of detection and delivery applications. In this work, the presence of specific pancreatic cancer miRNA (pre-miR-132) is detected utilizing the fluorescence properties of highly biocompatible nitrogen-doped graphene quantum dots (NGQDs). Methods: NGQDs were synthesized from Glucosamine HCl and deionized H2O. Cuvettes were filled with a mixture of bait ssDNA (13.7μM) and NGQDs (0.5 mg/ml) in deionized H2O that was vortexed for 5s before adding target strands. Samples were again vortexed for 5s and incubated at 4 ºC for 2hrs before excitation at 400 nm with an emission wavelength measured from 420 nm to 780 nm using a spectrofluorometer. Data analysis was performed using Origin software. Results: From the Zeta potential measurements, this platform is comprised of positively charged (1.14±0.36 mV) NGQDs binding with negatively charged (-22.4±6.00 mV) ssDNA electrostatically and/or via − stacking to form an NGQDs/ssDNA complex with an estimated size of 20 nm verified with TEM. Observing variations in fluorescence spectra of NGQDs/ssDNA complexes allows for the distinguishing of single-stranded and double-stranded DNA, as well as specific single-stranded DNA sequences due to bait-target complementarity. Furthermore, this enables detection of the loop of pre-miRNA of interest and can identify target miRNA from random controls with sensitivity in the nanomolar range. Conclusions: This approach allows for pancreatic cancer-specific miRNA sensing to facilitate pancreatic cancer detection at the early stages. Such early diagnosis is ultimately aimed to increase cancer patient survival rates

Detection of Pancreatic Cancer miRNA with Biocompatible Nitrogen-Doped Graphene Quantum Dots

Early-stage pancreatic cancer remains challenging to detect, leading to a poor five-year patient survival rate. This obstacle necessitates the development of early detection approaches based on novel technologies and materials. In this work, the presence of a specific pancreatic cancer-derived miRNA (pre-miR-132) is detected using the fluorescence properties of biocompatible nitrogen-doped graphene quantum dots (NGQDs) synthesized using a bottom-up approach from a single glucosamine precursor. The sensor platform is comprised of slightly positively charged (1.14 ± 0.36 mV) NGQDs bound via π-π stacking and/or electrostatic interactions to the negatively charged (-22.4 ± 6.00 mV) bait ssDNA; together, they form a complex with a 20 nm average size. The NGQDs\u27 fluorescence distinguishes specific single-stranded DNA sequences due to bait-target complementarity, discriminating them from random control sequences with sensitivity in the micromolar range. Furthermore, this targetability can also detect the stem and loop portions of pre-miR-132, adding to the practicality of the biosensor. This non-invasive approach allows cancer-specific miRNA detection to facilitate early diagnosis of various forms of cancer

Genotoxic effects of metabolic derivatives of the new drug phosphabenzide

Genotoxic action of four possible metabolites of the new tranquilizer phosphabenzide (acetylphosphabenzide, diphenylphosphinylacetic acid, phosphabenzide hydrazone with pyruvic acid, bis-1,2-(diphenylphosphinylacetyl)hydrazine) has been studied. These metabolites belong to slightly toxic phosphororganic compounds. The Ames Salmonella/microsomes tests performed on strains TA100 and TA98 showed that of these compounds only acetylphosphabenzide possessed mutagenic action. Metabolic activation of liver microsomes decreased the mutagenic effect. The mechanism of action of acetylphosphabenzide is likely to involve the formation of acetylhydrazine, capable of producing active electrophiles attacking DNA

Genotoxic Effects of Metabolic Derivatives of the New Drug Phosphabenzide

Genotoxic action of four possible metabolites of the new tranquilizer phosphabenzide (acetylphosphabenzide, diphenylphosphinylacetic acid, phosphabenzide hydrazone with pyruvic acid, bis-1,2-(diphenylphosphinylacetyl)hydrazine has been studied. These metabolites belong to slightly toxic phosphororganic compounds. The Ames Salmonella/microsomes tests performed on strains TA100 and TA98 showed that of these compounds only acetylphosphabenzide possessed mutagenic action. Metabolic activation of liver microsomes decreased the mutagenic effect. The mechanism of action of acetylphosphabenzide is likely to involve the formation of acetylhydrazine, capable of producing active electrophiles attacking DNA

γ-Iron Phase Stabilized at Room Temperature by Thermally Processed Graphene Oxide

© 2018 American Chemical Society. Stabilizing nanoparticles on surfaces, such as graphene, is a growing field of research. Thereby, iron particle stabilization on carbon materials is attractive and finds applications in charge-storage devices, catalysis, and others. In this work, we describe the discovery of iron nanoparticles with the face-centered cubic structure that was postulated not to exist at ambient conditions. In bulk, the γ-iron phase is formed only above 917 °C, and transforms back to the thermodynamically favored α-phase upon cooling. Here, with X-ray diffraction and Mössbauer spectroscopy we unambiguously demonstrate the unexpected room-temperature stability of the γ-phase of iron in the form of the austenitic nanoparticles with low carbon content from 0.60% through 0.93%. The nanoparticles have controllable diameter range from 30 nm through 200 nm. They are stabilized by a layer of Fe/C solid solution on the surface, serving as the buffer controlling carbon content in the core, and by a few-layer graphene as an outermost shell

Direct growth of oriented nanocrystals of gamma-iron on graphene oxide substrates. Detailed analysis of the factors affecting unexpected formation of the gamma-iron phase

© 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. In bulk, face-centered gamma-iron exists only at temperatures above 917 °C, returning back to body-centered alpha-iron upon cooling below this temperature. In this work, we report formation of the gamma-iron phase at temperatures significantly lower than the 917 °C threshold in the form of nanoparticles. Moreover, the as-grown nanoparticles have specific orientation along the (002) plane as the result of the templating effect of the graphene oxide substrate. Also, we provide a complete account of the factors responsible for the formation of the gamma-phase. Namely, we demonstrate the role of the type of carbon substrate, and the effect of the temperature and time of annealing and the graphene oxide/iron ion ratio. We demonstrate that the gamma-phase is not formed when using three-dimensional forms of carbon, elucidating the "magic" role of graphene oxide in this process

Direct growth of oriented nanocrystals of gamma-iron on graphene oxide substrates. Detailed analysis of the factors affecting unexpected formation of the gamma-iron phase

© 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. In bulk, face-centered gamma-iron exists only at temperatures above 917 °C, returning back to body-centered alpha-iron upon cooling below this temperature. In this work, we report formation of the gamma-iron phase at temperatures significantly lower than the 917 °C threshold in the form of nanoparticles. Moreover, the as-grown nanoparticles have specific orientation along the (002) plane as the result of the templating effect of the graphene oxide substrate. Also, we provide a complete account of the factors responsible for the formation of the gamma-phase. Namely, we demonstrate the role of the type of carbon substrate, and the effect of the temperature and time of annealing and the graphene oxide/iron ion ratio. We demonstrate that the gamma-phase is not formed when using three-dimensional forms of carbon, elucidating the "magic" role of graphene oxide in this process

Genotoxic Effects of Metabolic Derivatives of the New Drug Phosphabenzide

Genotoxic action of four possible metabolites of the new tranquilizer phosphabenzide (acetylphosphabenzide, diphenylphosphinylacetic acid, phosphabenzide hydrazone with pyruvic acid, bis-1,2-(diphenylphosphinylacetyl)hydrazine has been studied. These metabolites belong to slightly toxic phosphororganic compounds. The Ames Salmonella/microsomes tests performed on strains TA100 and TA98 showed that of these compounds only acetylphosphabenzide possessed mutagenic action. Metabolic activation of liver microsomes decreased the mutagenic effect. The mechanism of action of acetylphosphabenzide is likely to involve the formation of acetylhydrazine, capable of producing active electrophiles attacking DNA