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1.
J Colloid Interface Sci ; 607(Pt 1): 111-124, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34492348

RESUMO

Herein, a novel adsorbent based on carbon-modified zirconia/spinel ferrite (C@ ZrO2/Mn0.5Mg0.25Zn0.25Fe2O4) nanostructures were chemically prepared to remove 60Co and 152+154Eu radionuclides from liquid media using batch experiments. The XRD pattern confirms the successful preparation of the C@ZrO2/MnMgZnFe2O4 composite. Also, SEM and TEM images confirmed that the composite owns a heterogeneous morphology in the nanoscale range. The optical band gap value of Mn0.5Mg0.25Zn0.25Fe2O4, ZrO2, and the composite samples was 1.45, 2.38, and 1.54 eV, respectively. Many parameters have been studied as the effect of time, solution pH, and initial ion concentration. The kinetics models for the removal process of 152+154Eu and 60Co radionuclides were studied. The second-order kinetic equation could describe the sorption kinetics for both radionuclides. The Langmuir monolayer capacity for 60Co was 82.51 mg/g and for 152+154Eu was 136.98 mg/g. The thermodynamic parameters such as free energy ΔGo, the enthalpy ΔHo, and the entropy ΔSo were calculated. The results indicated that the sorption process has endothermic nature for both two radionuclides onto C@ZrO2/MnMgZnFe2O4 composite.


Assuntos
Nanoestruturas , Poluentes Químicos da Água , Adsorção , Óxido de Alumínio , Carbono , Cobalto , Európio , Compostos Férricos , Concentração de Íons de Hidrogênio , Cinética , Óxido de Magnésio , Soluções , Temperatura , Termodinâmica , Poluentes Químicos da Água/análise , Zircônio
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 265: 120378, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34543989

RESUMO

The structure of water, especially around the solute is thought to play an important role in many biological and chemical processes. Water-peptide and cosolvent-peptide interactions are crucial in determining the structure and function of protein molecules. In this work, we present the H-bonding analysis for model peptides like glycyl-glycine (gly-gly), glycine-ւ-valine (gly-val), glycyl-ւ-leucine (gly-leu) and triglycine (trigly) and triethylammonium based carboxylate protic ionic liquids (PILs) in aqueous solutions as well as for peptides in ∼0.2 mol·L-1 of aqueous PIL solutions in the spectral range of 7800-5500 cm-1 using Fourier transform near-infrared (FT-NIR) spectroscopy at 298.15 K. The hydration numbers for peptides and PILs were obtained using NIR method of simultaneous estimation of hydration spectrum and hydration number of a solute dissolved in water. The H-bond of water molecules around peptides and PILs are found to be stronger and shorter than those in pure liquid water. We observe that the hydration shell around zwitterions is a clathrate-like cluster of water in which ions entrap. Watery network analysis confirms that singly H-bonded species or NHBs changes to partial or distorted ice-like structures of water in the hydration shell of PILs. The overall water H-bonding in the hydration sphere of PILs increases in the order TEAF < TEAA < TEAG < TEAPy ≈ TEAP < TEAB. The influence of PILs on hydration behavior of peptides is explored in terms of H-bonding, cooperativity, hydrophobicity, water structural changes, ionic interactions etc.


Assuntos
Líquidos Iônicos , Glicina , Peptídeos , Soluções , Água
3.
J Colloid Interface Sci ; 607(Pt 2): 1813-1824, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34624723

RESUMO

The viscosity of a monoclonal antibody solution must be monitored and controlled as it can adversely affect product processing, packaging and administration. Engineering low viscosity mAb formulations is challenging as prohibitive amounts of material are required for concentrated solution analysis, and it is difficult to predict viscosity from parameters obtained through low-volume, high-throughput measurements such as the interaction parameter, kD, and the second osmotic virial coefficient, B22. As a measure encompassing the effect of intermolecular interactions on dilute solution viscosity, the Huggins coefficient, kh, is a promising candidate as a parameter measureable at low concentrations, but indicative of concentrated solution viscosity. In this study, a differential viscometry technique is developed to measure the intrinsic viscosity, [η], and the Huggins coefficient, kh, of protein solutions. To understand the effect of colloidal protein-protein interactions on the viscosity of concentrated protein formulations, the viscometric parameters are compared to kD and B22 of two mAbs, tuning the contributions of repulsive and attractive forces to the net protein-protein interaction by adjusting solution pH and ionic strength. We find a strong correlation between the concentrated protein solution viscosity and the kh but this was not observed for the kD or the b22, which have been previously used as indicators of high concentration viscosity. Trends observed in [η] and kh values as a function of pH and ionic strength are rationalised in terms of protein-protein interactions.


Assuntos
Anticorpos Monoclonais , Concentração de Íons de Hidrogênio , Concentração Osmolar , Osmose , Soluções , Viscosidade
4.
J Colloid Interface Sci ; 606(Pt 2): 2011-2023, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34749448

RESUMO

HYPOTHESIS: Deposits of biofluid droplets on surfaces (such as respiratory droplets formed during an expiratory) are composed of water-based salt-protein solution that may also contain an infection (bacterial/viral). The final patterns of the deposit formed and bacterial aggregation on the deposits are dictated by the fluid composition and flow dynamics within the droplet. EXPERIMENTS: This work reports the spatio-temporal, topological regulation of deposits of respiratory fluid droplets and control of bacterial aggregation by tweaking flow inside droplets using non-contact vapor-mediated interactions. Desiccated respiratory droplets form deposits with haphazard multiscale dendritic, cruciform-shaped precipitates when evaporated on a glass substrate. However, we showcase that short and long-range vapor-mediated interaction between the droplets can be used as a tool to control these deposits at nano-micro-millimeter scales. We morphologically control hierarchial dendrite size, orientation and subsequently suppress cruciform-shaped crystals by placing a droplet of ethanol in the vicinity of the biofluid droplet. Active living matter in respiratory fluids like bacteria is preferentially segregated and agglomerated without its viability and pathogenesis attenuation. FINDINGS: The nucleation sites can be controlled via preferential transfer of solutes in the droplets; thus, achieving control over crystal occurrence, growth dynamics, and the final topology of the deposit. For the first time, we have experimentally presented a proof-of-concept to control the aggregation of live active matter like bacteria without any direct contact. The methodology can have ramifications in biomedical applications like disease detection and bacterial segregation.


Assuntos
Gases , Cloreto de Sódio , Bactérias , Proteínas , Soluções
5.
Chemosphere ; 286(Pt 2): 131769, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34365171

RESUMO

Porous alumina has been shown to be an excellent adsorbent for Congo Red (CR) dye. In this work, highly porous g-Al2O3 nanoshells were synthesized from alumina coated carbon black (CB) obtained from a new deposition technique and used for removal of CR dye from aqueous solutions. Adsorption experiments were conducted in a batch mode and a series of parameters were investigated, including contact time, initial dye concentrations, ionic strength and pH of the solutions. It was found that equilibrium for CR adsorption can be reached within 30 min, much faster than reported by other studies in the literature on similar adsorbents. It was also found that the adsorption capacity of Al2O3 nanoshells is 44.8 % higher than that of alumina/CB. The adsorption capacity of Al2O3 nanoshells was more favorable at lower pH, and the optimal adsorption ability was achieved at pH 4.0 with a removal efficiency at 98.6 %. The Al2O3 nanoshells have a maximum adsorption capacity of 370.4 mg g-1 (25 °C; pH 7; no salt added), better than or comparable to those reported in the literature. A pseudo-second-order kinetics model can best fit the kinetics of CR adsorption, which follows the Langmuir isotherm. The high adsorption capacity is attributed to the strong hydrogen-bonding interactions between the anionic dye and Al2O3 nanoshells surface as well as to the electrostatic interactions between CR dye and the Al2O3 nanoshells.


Assuntos
Nanoconchas , Poluentes Químicos da Água , Adsorção , Óxido de Alumínio , Corantes , Vermelho Congo , Concentração de Íons de Hidrogênio , Cinética , Porosidade , Soluções
6.
Chemosphere ; 286(Pt 3): 131863, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34411928

RESUMO

Nanoplastic (NP) pollution is an emerging global concern due to its adverse impact on aquatic ecosystems. Nevertheless, the removal of aqueous NPs from aquatic environments remains a significant challenge. This study aims to investigate whether polystyrene NP in aqueous solutions can be removed using coffee grounds. Due to the difficulty associated with directly measuring NP levels and monitoring the biosorption process, we used fluorescent-orange amine-modified polystyrene beads (fluo-NP, 100 nm) to evaluate the efficacy of the biosorption process. The factors including pH, coffee grounds concentration, initial fluo-NP concentration, and contact time were optimized on batch experiments. In addition, the isotherm and kinetic models were employed to clarify the adsorption behaviors and mechanisms. It was found that aqueous fluo-NP particles were effectively adsorbed onto the coffee grounds over a wide pH range (pH 2-12), with a coffee ground concentration of 25 g/L leading to the maximum adsorption efficiency (74%). The equilibrium adsorption capacity of the coffee grounds was 4 mg/g for a reaction time of 40 min. Coffee grounds demonstrated the highest removal efficiency when the initial fluo-NP concentration was 100-125 mg/L. The Dubinin-Radushkevich model and pseudo-second-order model described the adsorption isotherm and kinetics well, respectively, and the adsorption at high fluo-NP concentration range was favorable. Moreover, the results suggest that the mechanism lies in the electrostatic interactions and hydrogen bonding between surface functional groups of the coffee grounds and the fluo-NP particles. Given that there is an urgent need to remove NPs from aqueous systems, this study illustrates that it is possible to use coffee ground biowaste for this purpose.


Assuntos
Café , Poluentes Químicos da Água , Adsorção , Ecossistema , Concentração de Íons de Hidrogênio , Cinética , Plásticos , Poliestirenos , Soluções , Termodinâmica , Poluentes Químicos da Água/análise
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 267(Pt 1): 120478, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34653851

RESUMO

An increasing amount of research has investigated whether direct contact ion pairs (CIP) exist in magnesium nitrate solutions. In this work, the relationship between the concentration and microstructure, as well as the details of the ion pair structure in magnesium nitrate solutions were studied by Raman spectroscopy, molecular dynamics (MD) simulations, and density functional theory (DFT) calculations. Component analysis showed that solvent-shared ion pairs (SIPs) and free hydrated ions were the dominant species in dilute solution. SIPs gradually transformed into contact ion pairs as the concentration increased. Complex structures and CIPs were the main species when WSR < 10, and as the concentration further increased, the CIP content gradually decreased, while the number of complex structures gradually increased. MD simulations and DFT calculations provide a new understanding of the structural units of ion pairs in magnesium nitrate solutions. The SIPs and CIPs were mainly composed of cationic triple ion clusters with two magnesium ions and one nitrate ion. The nitrate ion mainly existed as monodentate ligand to form a CIP with the magnesium ion. As the solution concentration increased, triple ion clusters gradually transformed into more complex chain structures. The structural complexity of magnesium nitrate solutions deserves further attention.


Assuntos
Magnésio , Água , Simulação de Dinâmica Molecular , Soluções , Análise Espectral Raman
8.
Int J Mol Sci ; 22(24)2021 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-34948206

RESUMO

In the context of the development of carriers for amino acids delivery, Spherical Mesoporous Silica Particles (SMSP), characterized by particles size ranging from 0.15 µm to 0.80 µm and average pore diameter of 2.4 nm, were synthesised and loaded with L-arginine (ARG), a basic amino acid involved in several physiological processes. The loading was performed using water as a solvent through the wet impregnation method (with a final arginine content of 9.1% w/w). The material was characterized before and after impregnation by means of X-Ray Diffraction (XRD), nitrogen sorption analysis, Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FT-IR) spectroscopy. SMSP are shown to suffer degradation upon impregnation, which dramatically affects their porosity. To elucidate the role of the pH of the ARG impregnating solution (originally set at pH ≈ 11) on SMSP degradation, the loading was performed under different pH conditions (5 and 9) keeping constant the ARG concentration. The impregnation performed with acidic solution did not modify the carrier. All samples displayed ARG in amorphous form: zwitterionic species were present in SMSP impregnated at basic pH whereas positive protonated species in that impregnated at acidic pH.


Assuntos
Arginina/química , Dióxido de Silício/química , Soluções/química , Água/química , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Transmissão/métodos , Nitrogênio/química , Tamanho da Partícula , Porosidade , Difração de Raios X/métodos
9.
Phys Chem Chem Phys ; 23(39): 22384-22394, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34608908

RESUMO

Ethanol is a common protein crystallization agent, precipitant, and denaturant, but also alters the dielectric properties of solutions. While ethanol-induced unfolding is largely ascribed to its hydrophobic parts, its effect on protein phase separation and inter-protein interactions remains poorly understood. Here, the effects of ethanol and NaCl on the phase behavior and interactions of protein solutions are studied in terms of the metastable liquid-liquid phase separation (LLPS) and the second virial coefficient B2 using lysozyme solutions. Determination of the phase diagrams shows that the cloud-point temperatures are reduced and raised by the addition of ethanol and salt, respectively. The observed trends can be explained using the extended law of corresponding states as changes of B2. The results for B2 agree quantitatively with those of static light scattering and small-angle X-ray scattering experiments. Furthermore, B2 values calculated based on inter-protein interactions described by the Derjaguin-Landau-Verwey-Overbeek (DLVO) potential and considering the dielectric solution properties and electrostatic screening due to the ethanol and salt content quantitatively agree with the experimentally observed B2 values.


Assuntos
Etanol/química , Muramidase/química , Proteínas/química , Muramidase/metabolismo , Soluções , Temperatura , Água/química
10.
Anal Chim Acta ; 1184: 339038, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34625271

RESUMO

Electromembrane extraction (EME), involving the migration of charged analytes across a supported liquid membrane (SLM) with an external power supply, is a promising sample preparation method in analytical chemistry. However, the presence of boundary double layers at the SLM/solution interfaces often restricts extraction efficiency. To avoid this, the current work proposed an ultrasound-assisted EME (UA-EME) method based on a novel type of supported semi-liquid membrane (SsLM). The characterizations showed that the SsLM was stable under ultrasound conditions. Ultrasound was found to reduce the boundary double layers and thus increase the mass transfer. Major operational parameters in UA-EME including ultrasound power density, temperature, applied voltage and extraction time were optimized with haloperidol, fluoxetine, and sertraline as model analytes. Under the optimal conditions, extraction recoveries of model analytes in water samples were in the range of 66.8%-91.6%. When this UA-EME method was coupled with LC-MS/MS for detection of the target analytes in human urine samples, the linear range of the analytical method was 10-1000 ng mL-1, with R2 > 0.997 for all analytes. The limits of detection (LOD) and limits of quantification (LOQ) were in the range of 1.7-2.1 ng mL-1 and 5.7-6.7 ng mL-1, respectively. The UA-EME expands the application field of ultrasound chemistry and will be very important in development of stable and fast sample preparation systems in the future.


Assuntos
Membranas Artificiais , Espectrometria de Massas em Tandem , Cromatografia Líquida , Humanos , Limite de Detecção , Soluções
11.
Soft Matter ; 17(42): 9624-9635, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34622265

RESUMO

Limited studies measure extensional rheology in protein solutions due to volume constraints and measurement challenges. We developed a small-volume, dripping-onto-substrate (DoS) extensional rheology device to measure the capillary thinning of protein and protein-excipient solutions via DoS for the first time. Ovalbumin (OVA) was used as a model system, examined via DoS both with and without excipient poloxamer 188 (P188). Water and dilute OVA break apart rapidly and demonstrate inertiocapillary (IC) thinning behavior, where longer breakup times in OVA can be attributed to lower surface tension. Further increasing OVA content leads to longer breakup times and deviations from IC thinning at the start of thinning, however, no evidence of elastic behavior is observed. P188 more effectively lowers the droplet surface tension than OVA, transitioning from IC behavior in dilute solution to weakly elastic behavior at higher concentrations. Combined protein/excipient formulations act synergistically at low concentrations, where breakup times are identical to those of the individual components despite the higher total concentration. However concentrated protein/excipient formulations exhibit elasticity, where extensional rheology parameters depend on P188 content and total concentration. These findings imply that excipients intended to stabilize proteins in shear flow can cause undesirable behavior in extensional flows like injection.


Assuntos
Excipientes , Elasticidade , Reologia , Soluções , Tensão Superficial , Viscosidade
12.
Int J Pharm ; 609: 121145, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34600056

RESUMO

The aim of the study is to investigate the thermal behavior of poloxamer 188 (P188) in binary (P188-water) and ternary (P188-trehalose-water) solutions during freezing and thawing. The thermal behavior of P188 in frozen (binary and ternary) systems was characterized by differential scanning calorimetry (DSC) and low-temperature X-ray powder diffractometry (XPRD) as a complementary technique. The influence of processing conditions (cooling rate, annealing) and a noncrystallizing co-solute (addition of trehalose) on the behavior of P188 was evaluated during freezing as well as thawing. In rapidly cooled (10 °C/min) aqueous binary solutions, P188 (10% w/v) was retained in the amorphous state. At slower cooling rates (0.5-5 °C/min), the extent of crystallization depended on the cooling rate. In ternary P188-trehalose-water systems (P188 4% w/v, trehalose 0-10% w/v), a concentration dependent inhibition of P188 crystallization was observed with increasing trehalose concentration. However, irrespective of trehalose concentration, annealing resulted in P188 crystallization. The presence of trehalose as well as the processing conditions (cooling rate and annealing) influenced the physical state of P188 at different stages of freezing and thawing. As the cooling rate decreased, the extent of P188 crystallization progressively increased. In presence of trehalose (≥4.0% w/v) crystallization of P188 (4.0% w/v) was inhibited and this effect could be reversed by annealing. Depending on the intended application, the physical form of P188 could be modulated, by annealing even in presence of a noncrystallizing solute.


Assuntos
Poloxâmero , Água , Varredura Diferencial de Calorimetria , Cristalização , Liofilização , Congelamento , Soluções , Trealose
13.
J Phys Chem B ; 125(40): 11308-11319, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34601874

RESUMO

The binding of group II metal cations such as Ca2+ and Mg2+ has been largely categorized as electrostatic or ionic using carboxylate symmetric and asymmetric stretching frequency assignments that have been historically used with little regard for the solvation environment of aqueous solutions. However, given the importance of these cations and their binding mechanisms related to biological function and in revealing surface enrichment factors for ocean to marine aerosol transfer, it is imperative that a deeper understanding be sought to include hydration effects. Here, infrared reflection-absorption and Raman spectra for surface and solution phase carboxylate binding information, respectively, are compared against bare (unbound) carboxylate and bidentate Zn2+:carboxylate spectral signatures. Spectral non-coincidence effect analysis, temperature studies, and spectral and potential of mean force calculations result in a concise interpretation of binding motifs that include the role of mediating water molecules, that is, contact and solvent-shared ion pairs. Calcium directly binds to the carboxylate group in contact ion pairs where magnesium rarely does. Moreover, we reveal the dominance of the solvent-shared ion pair of magnesium with carboxylate at the air-water interface and in solution.


Assuntos
Cálcio , Magnésio , Íons , Soluções , Água
14.
J Phys Chem B ; 125(42): 11673-11686, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34644091

RESUMO

Molecular crowding is a ubiquitous phenomenon in biological systems, with significant consequences on protein folding and stability. Small compounds, such as the osmolyte trimethylamine N-oxide (TMAO), can also present similar effects. To analyze the effects arising from these solute-like molecules, we performed a series of crowded coarse-grained folding simulations. Two well-known proteins were chosen, CI2 and SH3, modeled by the alpha-carbon-structure-based model. In the simulations, the crowding molecules were represented by low-sized neutral atom beads in different concentrations. The results show that a low level of the volume fraction occupied by neutral agents can change protein stability and folding kinetics for the two systems. However, the kinetics were shown to be unaffected in their respective folding temperatures. The faster kinetics correlates with changes in the folding route for systems at the same temperature, where non-native contacts were shown to be relevant. The transition states of the two systems with and without crowders are similar. In the case of SH3, there are differences in the structuring of two strands, which may be associated with the increase in its folding rate, in addition to the destabilization of the denatured ensemble. The present study also detected a crossover in the thermodynamic stability behavior, previously observed experimentally and theoretically. As the temperature increases, crowders change from destabilizing to stabilizing agents.


Assuntos
Dobramento de Proteína , Cinética , Estabilidade Proteica , Soluções , Termodinâmica
15.
Int J Mol Sci ; 22(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34639013

RESUMO

The electron density of a nanoparticle is a very important characteristic of the properties of a material. This paper describes the formation of silver nanoparticles (NPs) and the variation in the electronic state of an NP's surface upon the reduction in Ag+ ions with oxalate ions, induced by UV irradiation. The calculations were based on optical spectrophotometry data. The NPs were characterized using Transmission electron microscopy and Dynamic light scattering. As ~10 nm nanoparticles are formed, the localized surface plasmon resonance (LSPR) band increases in intensity, decreases in width, and shifts to the UV region from 402 to 383 nm. The interband transitions (IBT) band (≤250 nm) increases in intensity, with the band shape and position remaining unchanged. The change in the shape and position of the LSPR band of silver nanoparticles in the course of their formation is attributable to an increasing concentration of free electrons in the particles as a result of a reduction in Ag+ ions on the surface and electron injection by CO2- radicals. The ζ-potential of colloids increases with an increase in electron density in silver nuclei. A quantitative relationship between this shift and electron density on the surface was derived on the basis of the Mie-Drude theory. The observed blue shift (19 nm) corresponds to an approximately 10% increase in the concentration of electrons in silver nanoparticles.


Assuntos
Eletricidade , Elétrons , Nanopartículas Metálicas/química , Prata/química , Soluções/química , Fenômenos Químicos , Eletroquímica , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Modelos Teóricos , Tamanho da Partícula , Ressonância de Plasmônio de Superfície
16.
Sensors (Basel) ; 21(17)2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34502707

RESUMO

In this paper, we describe a low-cost microwave microfluidic system of ultrahigh sensitivity for detecting small changes in the concentration of polar solutions (liquid dielectrics) in the 2.4 GHz ISM band. Its principle of operation is based on microwave interferometry, which is implemented using planar microstrip lines and integrated microwave components. The key features of this system include small solution intake (<200 µL per measurement), short time of measurement (ca. 20 ms), ultrahigh sensitivity of concentration changes (up to 55 dB/%), and low error of measurement (below 0.1%). The ultrahigh sensitivity was proven experimentally by measurements of the fat content of milk. In addition, it is a user-friendly system due to an effortless and fast calibration procedure. Moreover, it can be made relatively compact (<20 cm2) and features low power consumption (200 mW). Thus, the proposed system is perfect for industrial applications, especially for highly integrated lab-on-chip devices.


Assuntos
Microfluídica , Micro-Ondas , Calibragem , Soluções
17.
PLoS One ; 16(9): e0256730, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495991

RESUMO

INTRODUCTION: Recently, electric cigarettes with liquid (e-liquid) were introduced as an alternative to tobacco smoking. They were promoted as possible cessation aids and were considered to be potentially less harmful than traditional tobacco-based cigarettes. However, there is little information on the toxicants present in e-liquids and their possible carcinogenic effects. METHODS: Western blot analysis was performed to identify the protein levels of cancer progression related signal transducers. Patient-derived brain tumor cells (CSC2) were injected into mouse brains and tumor growth was then observed by performing magnetic resonance imaging (MRI) and hematoxylin and eosin (H&E) staining of the whole brain. Immunohistochemistry (IHC) staining and Immunofluorescence staining were performed to study the expression of pEGFR and pERK. RESULTS: Western blotting revealed that e-liquids increased pEGFR and pERK expression in a dose dependent manner. Animal experiments revealed that the e-liquid treated group had accelerated tumor growth and poor prognosis compared to the vehicle group. Histological staining showed activation of pEGFR and pERK in the e-liquid treated group. CONCLUSION: Our study revealed that e-liquid activates pEGFR and pERK, leading to accelerated brain tumor growth and poor prognosis.


Assuntos
Neoplasias Encefálicas/metabolismo , Carcinogênese/efeitos dos fármacos , Sistemas Eletrônicos de Liberação de Nicotina , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glioblastoma/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Nicotina/administração & dosagem , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Neoplasias Encefálicas/patologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Fumar Cigarros/metabolismo , Modelos Animais de Doenças , Receptores ErbB/metabolismo , Feminino , Glioblastoma/patologia , Xenoenxertos/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias/métodos , Fosforilação/efeitos dos fármacos , Prognóstico , Propilenoglicol/administração & dosagem , Soluções , Solventes/administração & dosagem , Carga Tumoral/efeitos dos fármacos
18.
J Phys Chem B ; 125(39): 11036-11043, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34583505

RESUMO

The solvation of large, hydrophobic objects in water is facilitated by the formation of a low-density region surrounding the solute that is separated from the bulk liquid by an interface, which has a structure that resembles that between a liquid and its vapor. We study the effect of dissolved sodium chloride on the thermodynamics of solvation and on the solvent structure surrounding hydrophobic solutes in the size regime where this interface is not yet fully formed. Using biased Molecular Dynamics computer simulations, we calculate solvation free energies and orientational distributions of water molecules at different salt concentrations and solute sizes. We find that while the effects of sodium chloride on thermodynamic properties are small, the ions' response to the presence of a hydrophobic solute differs significantly from that of the water. Our findings provide mechanistic insight into how our understanding of hydrophobic solvation in water can be extended to electrolyte solutions.


Assuntos
Sais , Água , Interações Hidrofóbicas e Hidrofílicas , Soluções , Termodinâmica
19.
Biochem Biophys Res Commun ; 577: 110-115, 2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34509722

RESUMO

Phosphoryl guanidine oligonucleotides (PGOs) are promising uncharged analogs of nucleic acids and are used in a variety of applications. The importance of hydration is frequently ignored during the design of modified nucleic acid probes. Such hydrophobic modifications (phosphoryl guanidine) are expected to have a significant impact on the structure and thermal stability of the affected oligo with complementary nucleic acids. Here we aimed to investigate (by the osmotic stress method) hydration changes upon the formation of a duplex of a PGO with complementary DNA. According to our results, the presence of phosphoryl guanidines in one or both strands of a duplex only minimally affects hydration alterations under crowding conditions. The secondary structure of native and modified duplexes did not change significantly in the presence of ethanol, ethylene glycol, polyethylene glycol 200, or polyethylene glycol 1000. After the addition of a cosolvent, the thermodynamic stability of the PGO complexes changed in the same manner as that seen in a corresponding DNA duplex. The findings reported here and our previous studies form the basis for efficient use of PGOs in basic research and a variety of applications.


Assuntos
DNA/química , Guanidina/química , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico/métodos , Oligonucleotídeos/química , Termodinâmica , Dicroísmo Circular/métodos , DNA/genética , DNA/metabolismo , Etanol/química , Guanidina/metabolismo , Modelos Moleculares , Simulação de Dinâmica Molecular , Desnaturação de Ácido Nucleico , Ácidos Nucleicos/química , Ácidos Nucleicos/genética , Ácidos Nucleicos/metabolismo , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Polietilenoglicóis/química , Soluções/química
20.
J Phys Chem B ; 125(39): 11026-11035, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34570491

RESUMO

Cohesive interaction free energies entail an entropic component related to fluctuations of the energy associated with the attractive portion of the solute-solvent potential. The corresponding "fluctuation entropy" is fundamental in the solvation thermodynamics of macromolecular solutes and is linked to interfacial solvent density fluctuations and hydrophobic effects. Since the direct calculation of fluctuation entropy in molecular simulations is hampered by the poor sampling of high-energy tails in the solute-solvent energy distribution, indirect, and often approximate, routes for the calculation of fluctuation entropy are usually required, involving the modeling of geometrically frozen repulsive solute cavities in thermodynamic integration approaches. Herein, we propose a method to directly compute the fluctuation entropy by employing indirect umbrella sampling (INDUS). To validate the method, we consider model systems consisting of subnanometer oil droplets in water for which the fluctuation entropy can be computed exactly using indirect methods. The fluctuation entropy calculated with the newly proposed direct method agrees with the indirect reference calculations. We also observe that the solvation free energy and the contribution of the fluctuation entropy to it are of comparable magnitudes, particularly for larger oil droplets (∼1 nm). The proposed method can readily be employed for flexible macromolecular solutes and systems with extended hydrophobic surfaces or in the vicinity of a dewetting transition.


Assuntos
Água , Entropia , Soluções , Solventes , Termodinâmica
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