Spray nebulization enables polycaprolactone nanofiber production in a manner suitable for generation of scaffolds or direct deposition of nanofibers onto cells.

Spray nebulization is an elegant, but relatively unstudied, technique for scaffold production. Herein we fabricated mesh scaffolds of polycaprolactone (PCL) nanofibers via spray nebulization of 8% PCL in dichloromethane (DCM) using a 55.2 kPa compressed air stream and 17 ml h-1polymer solution flow rate. Using a refined protocol, we tested the hypothesis that spray nebulization would simultaneously generate nanofibers and eliminate solvent, yielding a benign environment at the point of fiber deposition that enabled the direct deposition of nanofibers onto cell monolayers. Nanofibers were collected onto a rotating plate 20 cm from the spray nozzle, but could be collected onto any static or moving surface. Scaffolds exhibited a mean nanofiber diameter of 910 ± 190 nm, ultimate tensile strength of 2.1 ± 0.3 MPa, elastic modulus of 3.3 ± 0.4 MPa, and failure strain of 62 ± 6%.In vitro, scaffolds supported growth of human keratinocyte cell epithelial-like layers, consistent with potential utility as a dermal scaffold. Fourier-transform infrared spectroscopy demonstrated that DCM had vaporized and was undetectable in scaffolds immediately following production. Exploiting the rapid elimination of DCM during fiber production, we demonstrated that nanofibers could be directly deposited on to cell monolayers, without compromising cell viability. This is the first description of spray nebulization generating nanofibers using PCL in DCM. Using this method, it is possible to rapidly produce nanofiber scaffolds, without need for high temperatures or voltages, yielding a method that could potentially be used to deposit nanofibers onto cell cultures or wound sites.

Inorganic/organic combination: Inorganic particles/polymer composites for tissue engineering applications.

Biomaterials have ushered the field of tissue engineering and regeneration into a new era with the development of advanced composites. Among these, the composites of inorganic materials with organic polymers present unique structural and biochemical properties equivalent to naturally occurring hybrid systems such as bones, and thus are highly desired. The last decade has witnessed a steady increase in research on such systems with the focus being on mimicking the peculiar properties of inorganic/organic combination composites in nature. In this review, we discuss the recent progress on the use of inorganic particle/polymer composites for tissue engineering and regenerative medicine. We have elaborated the advantages of inorganic particle/polymer composites over their organic particle-based composite counterparts. As the inorganic particles play a crucial role in defining the features and regenerative capacity of such composites, the review puts a special emphasis on the various types of inorganic particles used in inorganic particle/polymer composites. The inorganic particles that are covered in this review are categorised into two broad types (1) solid (e.g., calcium phosphate, hydroxyapatite, etc.) and (2) porous particles (e.g., mesoporous silica, porous silicon etc.), which are elaborated in detail with recent examples. The review also covers other new types of inorganic material (e.g., 2D inorganic materials, clays, etc.) based polymer composites for tissue engineering applications. Lastly, we provide our expert analysis and opinion of the field focusing on the limitations of the currently used inorganic/organic combination composites and the immense potential of new generation of composites that are in development.

Impact of Charge Transfer Complex on the Dielectric Relaxation Processes in Poly(methyl methacrylate) Polymer.

The impact of the charge transfer complex on the dielectric relaxation processes in free poly(methyl methacrylate) (PMMA) polymer sheets was investigated. The frequency dependence of dielectric properties was obtained over the frequency range 0.1 Hz-1 MHz at temperatures ranging between 303 K and 373 K for perylene dye and acceptors (picric acid (PA) and chloranilic acid (CLA)) in an in situ PMMA polymer. The TG/dTG technique was used to investigate the thermal degradation of the synthesized polymeric sheets. Additionally, the kinetic parameters have been assessed using the Coats-Redfern relation. The dielectric relaxation spectroscopy of the synthesized polymeric sheets was analyzed in terms of complex dielectric constant, dielectric loss, electrical modulus, electrical conductivity, and Cole-Cole impedance spectroscopy. α- and ß-relaxation processes were detected and discussed. The σ(ω) dispersion curves of the synthesized polymeric sheets show two distinct regions with increasing frequency. The impedance data of the synthesized polymeric sheets can be represented by the equivalent circuit (parallel RC).

Mesopores silica nanotubes-based sensors for the highly selective and rapid detection of Fe2+ ions in wastewater, boiler system units and biological samples.

Mesopores silica nanotubes (MSNTs)-based chemical sensors for the rapid detection and of highly selective Fe2+ ions have been prepared. The novel nanosensors were prepared via immobilization of 1,10-phenanthroline-5-amine (PA) and bathophenanthroline (BP) onto the MSNTs. The resultant PA and BP sensors display high sensitivity for detection the Fe2+ ions in tap water, river water, sea water, two units in simple cycle power station, and biological samples. More interestingly, upon meeting ultra-trace amount of Fe2+ ions, a red complex appears at once. Color changes can be seen from the naked eye and tracked with a smartphone or spectrophotometric techniques. The response time that is necessary to achieve a stable signal was less than 15 s. The Univariate (Univar) calibration technique had been utilized for the determination of figures of merits. The detection limit obtained from the digital image analysis was 19 ppb (7.04 × 10-7 M) for Fe2+ ions, while the obtained from the spectrophotometric method was 6.7 ppb (2.48 × 10-7 M). Therefore, the two sensors had been successfully used in the determination of Fe2+ in several real samples with high sensitivity and selectivity. In addition, they can be used as a simple, rapid, and portable method to detect and quantify the pre rust in any cooler system.

Charge-transfer complexation of TCNE with azithromycin, the antibiotic used worldwide to treat the coronavirus disease (COVID-19). Part IV: A comparison between solid and liquid interactions.

Finding a cure or vaccine for the coronavirus disease (COVID-19) is the most pressing issue facing the world in 2020 and 2021. One of the more promising current treatment protocols is based on the antibiotic azithromycin (AZM) alone or in combination with other drugs (e.g., chloroquine, hydroxychloroquine). We believe gaining new insight into the charge-transfer (CT) chemistry of this antibiotic will help researchers and physicians alike to improve these treatment protocols. Therefore, in this work, we examine the CT interaction between AZM (donor) and tetracyanoethylene (TCNE, acceptor) in either solid or liquid forms. We found that, for both phases of starting materials, AZM reacted strongly with TCNE to produce a colored, stable complex with 1:2 AZM to TCNE stoichiometry via a n → π* transition (AZM → TCNE). Even though both methodologies yielded the same product, we recommend the solid-solid interaction since it is more straightforward, environmentally friendly, and cost- and time-effective.

Data on charge-transfer interaction between 1-methyl-3-trifluoromethyl-2-pyrazoline-5-one with PA, CLA, TFQ, DDQ and TCNQ π-acceptors.

This article is related to a research paper entitled "Exploring the charge-transfer chemistry of fluorine-containing pyrazolin-5-ones: The complexation of 1-methyl-3-trifluoromethyl-2-pyrazoline-5-one with five π-acceptors" [J. Mol. Liq. 331 (2021) 115814] [1]. Herein we present photographic data that showed the color change after mixing methanolic solutions of 1-methyl-3-trifluoromethyl-2-pyrazoline-5-one (donor) with each of the investigated π-acceptor [picric acid (PA), chloranilic acid (CLA), fluoranil (TFQ), DDQ, and TCNQ]. Stoichiometry data for the interaction of the donor with all acceptors determined in solution state by the spectrophotometric titration method and the Job's continuous variation method were presented. The data presented are useful for understand that the charge-transfer (CT) complexation between a donor and an acceptor, generally, is characterized by a strong color change, and to understand the stoichiometry between these molecules.

Charge-transfer interaction of aspartame and neotame with several π-acceptors: Stoichiometric data.

This data article is related to a research paper entitled ``Correlations between spectroscopic data for charge-transfer complexes of two artificial sweeteners, aspartame and neotame, generated with several π-acceptors'' [J. Mol. Liq. 333 (2021) 115904] [1]. Herein we present stoichiometric data of charge-transfer (CT) complexes generated from the interaction between aspartame and neotame with three π-acceptors in methanol solvent at room temperature. The investigated π-acceptors were picric acid (PA), chloranilic acid (CA), and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), where the methods used to determine the stoichiometry of the CT interaction were the spectrophotometric titration method and the Job's continuous variation method.

Chloroquine and hydroxychloroquine inhibitors for COVID-19 sialic acid cellular receptor: Structure, hirshfeld atomic charge analysis and solvent effect.

COVID-19, the pandemic disease recently discovered in Wuhan (China), severely spread and affected both social and economic activity all over the world. Attempts to find an effective vaccine are challenging, time-consuming though interminable. Hence, re-proposing effective drugs is reliable and effective alternative. Taking into account the genome similarity of COVID-19 with SARS-CoV, drugs with safety profiles could be fast solution. Clinical trials encouraged the use of Chloroquine and Hydroxychloroquine for COVID-19 inhibition. One of the possible inhibition pathways is the competitive binding with the angiotension-converting enzyme-2 (ACE-2), in particular with the cellular Sialic acid (Neu5Ac). Here, we investigate the possible binding mechanism of ClQ and ClQOH with sialic acid both in the gas phase and in water using density functional theory (DFT). We investigated the binding of the neutral, monoprotonated and diprotonated ClQs and ClQOHs to sialic acid to simulate the pH effect on the cellular receptor binding. DFT results reveals that monoprotonated ClQ+ and ClQOH+, which account for more than 66% in the solution, possess high reactivity and binding towards sialic acid. The Neu5Ac-ClQ and the analogues Neu5Ac-ClQOH adducts were stabilized in water than in the gas phase. The molecular complexes stabilize by strong hydrogen bonding and π - π stacking forces. In addition, proton-transfer in Neu5Ac-ClQOH+ provides more stabilizing power and cellular recognition binding forces. These results shed light on possible recognition mechanism and help future breakthroughs for COVID-19 inhibitors.