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Thermodynamic behavior and polymorphism of 1-butyl-3-methylimidazolium hexafluorophosphate composites with multiwalled carbon nanotubes.

ABSTRACT: Based on room-temperature densities measured in this research for ionic nanofluids (INFs) with four ionic liquids (ILs), we conclude that evacuation is a necessary step to maximize the IL penetration into multiwalled carbon nanotubes (MWCNT). An improved procedure for reproducible preparation of INFs is proposed. Thermal behavior of five (1-butyl-3-methylimidazolium hexafluorophosphate + MWCNT) samples was studied by adiabatic calorimetry over the temperature range (78 to 370) K. The samples contained from 0.11 to 0.92 mass fraction of the nanophase. Their appearance changed from the fluid to the powder with increasing the MWCNT content. For the fluid samples, the specific heat capacity was found be an additive quantity of the specific heat capacities of the components for the crystal and liquid phases, and the temperatures of phase transitions did not change relative to the bulk values. For the powder-like sample with the highest IL content, a sigmoidal heat capacity curve was observed. Thus, the internal diameter of the studied MWCNT was small enough to switch from the isothermal melting process to the gradual transition from the crystal-like structures to the liquid-like ones.

SUBMITTER: Liavitskaya T

PROVIDER: S-EPMC7745233 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Thermodynamic behavior and polymorphism of 1-butyl-3-methylimidazolium hexafluorophosphate composites with multiwalled carbon nanotubes.

Liavitskaya Tatsiana T Paulechka Eugene E Blokhin Andrey V AV Shevelyova Marina M

The Journal of chemical thermodynamics 20190101

Based on room-temperature densities measured in this research for ionic nanofluids (INFs) with four ionic liquids (ILs), we conclude that evacuation is a necessary step to maximize the IL penetration into multiwalled carbon nanotubes (MWCNT). An improved procedure for reproducible preparation of INFs is proposed. Thermal behavior of five (1-butyl-3-methylimidazolium hexafluorophosphate + MWCNT) samples was studied by adiabatic calorimetry over the temperature range (78 to 370) K. The samples con ...[more]

PMID: 33343024

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Project description:Multiwalled carbon nanotubes (MWCNTs) regularly enter aquatic environments due to their ubiquity in consumer products and engineering applications. However, the effects of MWCNT pollution on the environmental microbiome are poorly understood. Here, we evaluated whether these carbon nanoparticles can elevate the spread of antimicrobial resistance by promoting bacterial plasmid transfer, which has previously been observed for copper nanomaterials with antimicrobial properties as well as for microplastics. Through a combination of experimental liquid mating assays between Pseudomonas putida donor and recipient strains with plasmid pKJK5::gfpmut3b and mathematical modeling, we here demonstrate that the presence of MWCNTs leads to increased plasmid transfer rates in a concentration-dependent manner. The percentage of transconjugants per recipient significantly increased from 0.21 ± 0.04% in absence to 0.41 ± 0.09% at 10 mg L-1 MWCNTs. Similar trends were observed when using an Escherichia coli donor hosting plasmid pB10. The identified mechanism underlying the observed dynamics was the agglomeration of MWCNTs. A significantly increased number of particles with >6 μm diameter was detected in the presence of MWCNTs, which can in turn provide novel surfaces for bacterial interactions between donor and recipient cells after colonization. Fluorescence microscopy confirmed that MWCNT agglomerates were indeed covered in biofilms that contained donor bacteria as well as elevated numbers of green fluorescent transconjugant cells containing the plasmid. Consequently, MWCNTs provide bacteria with novel surfaces for intense cell-to-cell interactions in biofilms and can promote bacterial plasmid transfer, hence potentially elevating the spread of antimicrobial resistance. IMPORTANCE In recent decades, the use of carbon nanoparticles, especially multiwalled carbon nanotubes (MWCNTs), in a variety of products and engineering applications has been growing exponentially. As a result, MWCNT pollution into environmental compartments has been increasing. We here demonstrate that the exposure to MWCNTs can affect bacterial plasmid transfer rates in aquatic environments, an important process connected to the spread of antimicrobial resistance genes in microbial communities. This is mechanistically explained by the ability of MWCNTs to form bigger agglomerates, hence providing novel surfaces for bacterial interactions. Consequently, increasing pollution with MWCNTs has the potential to elevate the ongoing spread of antimicrobial resistance, a major threat to human health in the 21st century.

Project description:Multiwalled carbon nanotubes (MWCNTs) are cylindrical tubes of graphitic carbon with unique physical and electrical properties. MWCNTs are being explored for a variety of diagnostic and therapeutic applications. Successful biomedical application of MWCNTs will require compatibility with normal circulatory components, including constituents of the hemostatic cascades. In this manuscript, we compare the thrombotic activity of MWCNTs in vitro and in vivo. We also assess the influence of functionalization of MWCNTs on thrombotic activity. In vitro, MWCNT activate the intrinsic pathway of coagulation as measured by activated partial thromboplastin time (aPTT) assays. Functionalization by amidation or carboxylation enhances this procoagulant activity. Mechanistic studies demonstrate that MWCNTs enhance propagation of the intrinsic pathway via a non-classical mechanism strongly dependent on factor IX. MWCNTs preferentially associate with factor IXa and may provide a platform that enhances its enzymatic activity. In addition to their effects on the coagulation cascade, MWCNTs activate platelets in vitro, with amidated MWCNTs exhibiting greater platelet activation than carboxylated or pristine MWCNTs. However, contrasting trends are obtained in vivo, where functionalization tends to diminish rather than enhance procoagulant activity. Thus, following systemic injection of MWCNTs in mice, pristine MWCNTs decreased platelet counts, increased vWF, and increased D-dimers. In contrast, carboxylated MWCNTS exhibited little procoagulant tendency in vivo, eliciting only a mild and transient decrease in platelets. Amidated MWCNTs elicited no statistically significant change in platelet count. Further, neither carboxylated nor amidated MWCNTs increased vWF or D-dimers in mouse plasma. We conclude that the procoagulant tendencies of MWCNTs observed in vitro are not necessarily recapitulated in vivo. Further, functionalization can markedly attenuate the procoagulant activity of MWCNTs in vivo. This work will inform the rational development of biocompatible MWCNTs for systemic delivery.

Dataset Information

Thermodynamic behavior and polymorphism of 1-butyl-3-methylimidazolium hexafluorophosphate composites with multiwalled carbon nanotubes.

Publications

Thermodynamic behavior and polymorphism of 1-butyl-3-methylimidazolium hexafluorophosphate composites with multiwalled carbon nanotubes.

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