MATERIALS CHEMISTRY AND PHYSICS

Zirconia toughened fluorosilicate glass-ceramics for dental prosthetic restorations
Gali S, Arjun A and Premkumar HB
Dental glass-ceramics have limited strength and are unsuitable for high-stress-bearing areas. Zirconia stands out as a popular choice for reinforcing dental glass-ceramics due to its biocompatibility and high fracture toughness.
Curcumin and Vitamin C dual release from Hydroxyapatite coated Ti6Al4V discs enhances biological properties
Majumdar U and Bose S
Titanium alloys are widely used as implant materials due to their biocompatibility and superior mechanical properties for high-load-bearing applications. However, one of the major challenges is their inferior bioactivity and osseoconductivity. Hydroxyapatite is widely used as an alternative material for bone implants due to its compositional similarity to natural bone. In this study, hydroxyapatite is coated on Ti6Al4V discs to enhance its bioactivity. The coated discs are drop-casted with curcumin in the lower layer and vitamin C in the upper layer. This study aims to evaluate the effects of this dual drug delivery system on osteoblast cell proliferation, inhibition of osteoclastogenesis, chemo-preventive and infection control properties. The coating strength obtained is 22 ± 2 MPa. The release from the dual delivery system shows a 1.5-fold increase in osteoblast cell viability, a 1.5-fold reduction in osteoclast cell differentiation, a 2-fold decrease in osteosarcoma growth. The release of curcumin demonstrates a 94% antibacterial efficacy, while the release of vitamin C exhibits an efficacy of 98.6% aganist . This multifunctional system can be used as a potential implant for load-bearing applications.
Preparation and characterization of intelligent thermochromic fabric coatings for the detection of fever diseases
Civan L and Kurama S
Real-time monitoring of changes in skin temperature with smart thermochromic fabrics that act as sensors is extremely important in the early diagnosis of febrile diseases such as the COVID-19 epidemic that endanger public health. In this context, the study aims to detect fever, which is the immune response of the body, as a symptom in the diagnosis of various diseases and to prepare a thermochromic functional fabric by coating method to reduce the risk of contamination. For this purpose, a composition containing green pigment and zinc acetate dihydrate as the starting material was prepared using the sol-gel method. The prepared composition was applied to calico and alpaca fabric, and it was provided to show transformation at 37.5 °C with the effect of the pigment, which had a color change feature at 33 °C. The samples were analyzed using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) characterization methods. The results showed that it was possible to change the active conversion temperature of the pigment from 33 °C to 37.5 °C, depending on the composition. The use of the compositions developed in this study in alpaca fabric coating provides an area of use as an indicator if the human body temperature reaches 37.5 °C, which is considered the concept of fever.
Non-enzymatic electrochemical sensing of dopamine from COVID-19 quarantine person
Masood T, Asad M, Riaz S, Akhtar N, Hayat A, Shenashen MA and Rahman MM
The worldwide outbreak of COVID-19 pandemic, is not only a great threat to the victim life but it is leaving invisible devastating negative affect on mental health of quarantined individual because of isolation, depression, bereavement, and loss of income. Therefore, the precise monitoring catecholamine neurotransmitters specifically of dopamine (DA) is of great importance to assess the mental health. Thus, herein we have synthesized Co-based zeolitic imidazolate framework (ZIF-67) through solvothermal method for precise monitoring of DA. To facilitate the fast transportation of ions, highly conductive polymer, poly(3,4-ethylenedioxythiophene; PEDOT) has been integrated on the surface of ZIF-67 which not only provides the smooth pathway for ions/electrons transportation but also saves the electrode from pulverization. The fabricated ZIF-67/PEDOT electrode shows a significant sensing performance towards DA detection in terms of short diffusion pathways by expositing more active sites, over good linear range (15-240 μM) and a low detection limit of (0.04 μM) even in the coexistence of the potentially interfering molecules. The developed ZIF-67/PEDOT sensor was successfully employed for sensitive and selective monitoring of DA from COVID-19 quarantined person blood, thus suggesting reliability of the developed electrode.
Nano drug (AgNPs capped with hydroxychloroquine): Synthesis, characterization, anti-covid-19 and healing the wound infected with S. aureus
H Ali A, A Alheety M, Hasen Alubaidy M and Dohare S
Almost existing anti-viral drugs are only organic molecules that are able to circumvent the system the virus works with, which leaves it facing the immune system of our bodies and then kills it. Unfortunately, this type of pharmacological fight did not succeed in a way to overcome this virus, so it became necessary to think outside the box, to find a drug that would kill the virus or alter its protein structure. This research aims to prepare silver nanoparticle (AgNPs) by the green method depending on the reaction of the silver nitrate (safe for humans) with the phoenix dactylifera extract (safe for humans) and then coated with the hydroxychloroquine (HQ, known antiviral drug). This substance will fight the virus with different mechanisms (i) silver will carry the drug to cells easily, and then (ii) nano silver will perform a physical inhibition of the virus and thus reduce its susceptibility to binding to host cells. In addition, (iii) silver nanoparticle is much smaller than the size of the virus which qualifies it to cross into the virus and change the structure of RNA. Furthermore, (iv) it is possible for silver to interact with the amino and carboxylic ends in the virus proteins. The results of TCID50 shows that the prepared nano drug is able to reduce the viability of covid-19 to about 22% using 400 mg/ml of AgNPs/HQ. The resulted nanodrug was also used for healing the wound infected with S. aureus and the histological results revealed that all of the disease symptoms improved, with the epidermal layer multiplying quickly and the infected wounds healing quickly.
Ag-enriched TiO nanocoating apposite for self-sanitizing/ self-sterilizing/ self-disinfecting of glass surfaces
Khan GR and Malik SI
The excellent strategy to mitigate the spread of the COVID-19 pandemic is to inhibit the transmission of the SARS-CoV-2. Since fomites are one of the vital routes of coronaviral transmission, disinfecting of fomites play a pivotal role in curbing its survival on the contaminated surfaces. Available commercial disinfectants cannot keep the contaminated surfaces sanitized all the time. Self-disinfecting ability of Ag-enriched TiO nanocoating due to its superb photocatalytic efficiency can effectively reduce infections caused by spread of pathogens at public places. Anatase Ag-TiO nanocoatings synthesized by sol-gel process at 0.5, 1.5, and 2.5% enriching concentrations were casted on glass substrates by spin-coating technique and subsequently annealed at 650 °C. The morphological shape, crystallographic structure, light absorbance, photo-luminosity, vibrational modes, and functional groups of Ag-TiO nanocoating on glass surface were studied by FE-SEM, GIXRD, UV-Visible, Photoluminescence, Raman, and FTIR spectroscopy. The developed anatase Ag-TiO nanocoatings manifested to improve photocatalytic disinfecting performance due to the achieved small crystallite size of 10.5-19.2 nm, diminished band gap energy of 2.56-2.60 eV, elevated surface area of 0.802-1.470 ×10 cm/g, and enhanced light absorbance. Among the enriched specimens, 0.5% Ag-TiO nanocoatings predicted an overall exalted functionality compared to pristine one.
Atomistic insight into 2D COFs as antiviral agents against SARS-CoV-2
Jahromi AM, Solhjoo A, Ghasemi M, Khedri M, Maleki R and Tayebi L
The recent pandemic of COVID-19 has raised global health concerns. Preventing severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) activity in the body is a very promising method to overcome the COVID-19 pandemic. One of the prevention methods is constraining the binding process among the human cell receptor-ACE2 and coronavirus spike protein. In the research done, the effect of deformation of the spike protein structure, due to the covalent organic frameworks (COFs), in reducing the interactions of ACE2 and the spike protein by the computational method was investigated. In this regard, atomic analysis of the interactions of ACE2 and the spike protein is provided using a molecular dynamics simulation. First, we investigated the interactions of the three different COFs, including COF-78, DAAQ-TFP, and COF-OEt, with the spike protein by analyzing the bond energies, as well as structural changes of the spike protein. Then, intermolecular interactions of the deformed spike protein along with ACE2 were assessed to clarify the protein's fusion after the deformation. As indicated by the results, although all introduced COFs deformed the spike protein in an effective way, COF-78 showed the best performance in the prevention of spike protein-ACE2 interactions by changing the molecular structure of the protein. Indeed, the interaction analysis of the deformed spike protein by COF-78 with the ACE2 showed that their interactions had the lowest absolute value of energy, along with the least amount of hydrogen bonds, in which the compaction of the protein was lower compared to the other deformed proteins. Moreover, having a high contact area with an aqueous media as well as severe fluctuations during the simulation time confirmed the positive performance of COF-78. In the current study, we aimed to introduce novel materials and COVID-19 prevention methodology that can be used in face masks and for surface disinfection.
Electrochemical fabrication of TiO micro-flowers for an efficient intracellular delivery using nanosecond light pulse
Mohan L, Kar S, Nagai M and Santra TS
Introduction of foreign cargo into the targeted living cell with high transfection efficiency and high cell viability is an important mean for many biological and biomedical research purpose. Here, we have demonstrated a newly developed Titanium oxide micro-flower structure (TMS) for intracellular delivery. The TMS were formed on titanium (Ti) substrate using an electrochemical anodization process. The TMS consists of branches of titanium dioxide (TiO) nanotubes, which play an important role in efficient cargo delivery. Due to nanosecond pulse laser exposure, Ti substrate heat-up, generating cavitation bubbles. These bubbles can rapidly grow, coalesce, and collapse to induce explosion resulting in very strong fluid flow through the TiO nanotubes and disrupt the cell plasma membrane promoting the delivery of biomolecules into cells. Using this platform, we successfully deliver dyes with 93% efficiency and nearly 98% cell viability into HCT cells, and this technique is potentially applicable for cellular therapy and diagnostics.
The impact of polymer additive for N95 masks on gamma-ray attenuation properties
Kilicoglu O, Kara U and Inanc I
This article explores the effectiveness of gamma rays attenuation of various N95 respirator samples by analysing several theoretical parameters such as the Effective Atomic Numbers (Z), Half Value Layer (HVL), Mean Free Path (MFP), Mass Attenuation Coefficients (MAC), Tenth Value Layer (TVL), Exposure Build Up Factors (EBF) and Energy Absorption Build Up Factors (EABF). For the selected N95 mask samples, the MAC values corresponding to the energy levels between 0.015 and 20 MeV are measured using the WinXCOM software and the MATLAB code. The parameters including Z, TVL, HVL, and MFP are computed using the MAC values derived from the WinXCOM program. EBF and EABF are computed in relation to the penetration depth and incident photon energy by using the (G-P) fitting approximation in estimating the photon build-up factor. The findings showed that having the lowest TVL, HVL, and MFP, the N2 sample has the best output in terms of radiation attenuation purposes. In conclusion, the N2 sample which outperforms other samples is the most promising mask sample when it comes to gamma-ray attenuation features.
Review on 3D printing: Fight against COVID-19
Oladapo BI, Ismail SO, Afolalu TD, Olawade DB and Zahedi M
The outbreak of coronavirus disease in 2019 (COVID-19) caused by the SARS-CoV-2 virus and its pandemic effects have created a demand for essential medical equipment. To date, there are no specific, clinically significant licensed drugs and vaccines available for COVID-19. Hence, mapping out COVID-19 problems and preventing the spread with relevant technology are very urgent. This study is a review of the work done till October, 2020 on solving COVID-19 with 3D printing. Many patients who need to be hospitalized because of COVID-19 can only survive on bio-macromolecules antiviral respiratory assistance and other medical devices. A bio-cellular face shield with relative comfortability made of bio-macromolecules polymerized polyvinyl chloride (BPVC) and other biomaterials are produced with 3D printers. Summarily, it was evident from this review study that additive manufacturing (AM) is a proffered technology for efficient production of an improved bio-macromolecules capable of significant COVID-19 test and personal protective equipment (PPE) to reduce the effect of COVID-19 on the world economy. Innovative AM applications can play an essential role to combat invisible killers (COVID-19) and its hydra-headed pandemic effects on humans, economics and society.
Binder-free TiO hydrophilic film covalently coated by microwave treatment
Luo Y, Wang L, Hwang Y, Yu J, Lee J, Liu Y, Wang H, Kim J, Song HY and Lee H
A binder-free attachment method for TiO on a substrate has been sought to retain high active photocatalysis. Here, we report a binder-free covalent coating of phase-selectively disordered TiO on a hydroxylated silicon oxide (SiO) substrate through rapid microwave treatment. We found that Ti-O-Si and Ti-O-Ti bonds were formed through a condensation reaction between the hydroxyl groups of the disordered TiO and Si substrate, and the disordered TiO nanoparticles themselves, respectively. This covalent coating approach can steadily hold the active photocatalytic materials on the substrates and provide long-term stability. The binder-free disordered TiO coating film can have a thickness (above 38 μm) with high surface integrity with a strong adhesion force (15.2 N) against the SiO substrate, which leads to the production of a rigid and stable TiO film. This microwave treated TiO coating film showed significant volatile organic compounds degradation abilities under visible light irradiation. The microwave coated selectively reduced TiO realized around 75% acetaldehyde degradation within 12 h and almost 90% toluene degradation after 9 h, also retains stable photodegradation performance during the cycling test. Thus, the microwave coating approach allowed the preparation of the binder-free TiO film as a scalable and cost-effective method to manufacture the TiO film that shows an excellent coating quality and strengthens the application as a photocatalyst under severe conditions.
Au nanoparticles for SERS: Temperature-controlled nanoparticle morphologies and their Raman enhancing properties
Darienzo RE, Chen O, Sullivan M, Mironava T and Tannenbaum R
Quasi-fractal gold nanoparticles can be synthesized via a modified and temperature controlled procedure initially used for the synthesis of star-like gold nanoparticles. The surface features of nanoparticles lead to improved enhancement of Raman scattering intensity of analyte molecules due to the increased number of sharp surface features possessing numerous localized surface plasmon resonances (LSPR). The LSPR is affected by the size and shape of surface features as well as inter-nanoparticle interactions, as these affect the oscillation modes of electrons on the nanoparticle surfaces. The effect of the particle morphologies on the localized surface plasmon resonance (LSPR) and on the surface-enhancing capabilities of these nanoparticles is explored by comparing different nanoparticle morphologies and concentrations. We show that in a fixed nanoparticle concentration regime, quasi-fractal gold nanoparticles (gold nanocaltrop) provide the highest level of surface enhancement, whereas spherical nanoparticles provide the largest enhancement in a fixed gold concentration regime. The presence of highly branched features enables these nanoparticles to couple with a laser wavelength, despite having no strong absorption band and hence no single surface plasmon resonance. This cumulative LSPR may allow these nanoparticles to be used in a variety of applications in which laser wavelength flexibility is beneficial, such as in medical imaging applications where fluorescence at short laser wavelengths may be coupled with non-fluorescing long laser wavelengths for molecular sensing.
AgS nanocrystallites deposited over polyamidoamine grafted carbon nanotubes: An efficient NIR active photothermal agent
Neelgund GM, Okolie MC, Williams FK and Oki A
A novel NIR (near infrared) active photothermal agent, CNTs-PAMAM-AgS has been synthesized by covalent grafting of polyamidoamine (PAMAM) to carbon nanotubes (CNTs) and subsequent deposition of AgS nanocrystallites. The potential of CNTs-PAMAM-AgS as a NIR active photothermal agent was preliminarily accessed by its electronic absorption spectrum measured in UV-vis-NIR region. The CNTs-PAMAM-AgS exhibited excellent photothermal effect and photothermal conversion efficiency of 26% under illumination with 980 nm laser, the efficiency was found to be higher than popular gold and copper based photothermal agents. Temperature attained by CNTs-PAMAM-AgS during measurement of its photothermal effect was 64.7 °C at 1 g/mL, which far exceeds the temperature tolerance level of cancer cells. So that CNTs-PAMAM-AgS could destroy the cancer cells in an effective manner. Furthermore, it was found the linear dependence of photothermal effect of CNTs-PAMAM-AgS over its concentration. CNTs-PAMAM-AgS possessed excellent stability against photo-bleaching and photo-corrosiveness. In consideration of its outstanding photothermal effect and photothermal conversion efficiency, CNTs-PAMAM-AgS could be a promising photothermal agent to employ in future photothermal therapy.
Novel magnetic core-shell nanoparticles for the removal of polychlorinated biphenyls from contaminated water sources
Gutierrez AM, Bhandari R, Weng J, Stromberg A, Dziubla TD and Hilt JZ
In this work, we developed novel core-shell nanoparticle systems with magnetic core and polymer shell via atom transfer radical polymerization for use as high affinity nanoadsorbents for organic contaminants in water and wastewater treatment. Polyphenolic-based moieties, curcumin multiacrylate (CMA) and quercetin multiacrylate (QMA), were incorporated into poly(ethylene glycol) (PEG) based polymeric shells to create high affinity binding sites for the capture of polychlorinated biphenyls (PCBs) as a model pollutant. The resulting magnetic nanoparticles (MNPs) were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and UV-visible spectroscopy. The affinity of these novel materials for PCB 126 was evaluated and fitted to the nonlinear Langmuir model to determine binding affinities (KD). The KD values obtained were: PEG MNPs (8.42 nM) < IO MNPs (8.23nM) < QMA MNPs (5.88 nM) < CMA MNPs (2.72 nM), demonstrating that the presence of polyphenolic-based moieties enhanced PCB 126 binding affinity, which is hypothesized to be a result of π - π stacking interactions. These values are lower that KD values for activated carbon, providing strong evidence that these novel core-shell nanoparticles have a promising application as nanoadsorbents for specific organic contaminants offering a cost effective alternative to current remediation approaches.
Corrosion behavior of plasma electrolytically oxidized gamma titanium aluminide alloy in simulated body fluid
Lara Rodriguez L and Sundaram PA
Plasma electrolytic oxidized (PEO) γTiAl alloy samples were electrochemically characterized by open circuit potential (OCP), cyclic polarization and electrochemical impedance spectroscopy (EIS) to evaluate their corrosion resistance in simulated body fluid (SBF) in order to gauge their potential for biomedical applications. Experimental results through OCP and cyclic polarization studies demonstrated the protective nature and the beneficial effect of the PEO coatings on γTiAl. The PEO surface increased corrosion resistance of these surface modified alloys. EIS data indicated the presence of an underlying compact oxide layer with surface pores represented by two domes in the Nyquist plots. Electrical equivalent circuits to describe the EIS results are proposed.
Direct Dry-Grinding Synthesis of Monodisperse Lipophilic CuS Nanoparticles
Li Y, Scott J, Chen YT, Guo L, Zhao M, Wang X and Lu W
Copper sulfide nanoparticles, effective absorbers of near-infrared light, are recently attracting broad interest as a photothermal coupling agent for cancer therapy. Lipophilic copper sulfide nanoparticles are preferred for high performance biomedical applications due to high tissue affinity. Synthesis of lipophilic copper sulfide nanoparticles requires complicated multi-step processes under severe conditions. Here, we describe a new synthetic process, developed by direct dry-grinding of copper(II) acetylacetonate with sulfur under ambient environment at low temperature. The formed CuS nanoparticles are of uniform size, ~10 nm in diameter, and are monodispersed in chloroform. Each covellite CuS nanocrystal surface is modified with oleylamine through hydrogen bonding between sulfur atoms and amine groups of oleylamine. The nanoparticles demonstrate near-infrared light absorption for photothermal applications. The synthetic methodology described here is more convenient and less extreme than previous methods, and should thus greatly facilitate the preparation of photothermal lipophilic copper sulfide nanomaterials for cancer therapy.
The effects of synthesis method on the physical and chemical properties of dextran coated iron oxide nanoparticles
Hauser AK, Mathias R, Anderson KW and Hilt JZ
Iron oxide nanoparticles coated with dextran were synthesized via four variations on the co-precipitation method. The methods ranged from formation of the nanoparticles within the dextran solution to the adsorption of dextran to the nanoparticle surface following nucleation and extensive washing. The timing of the addition of dextran into the reaction mixture was found to greatly influence the physical and chemical properties of the magnetic nanoparticles. Batches of dextran coated iron oxide nanoparticles were synthesized by each method in triplicate, and the nanoparticles were further crosslinked with epichlorohydrin. The properties of the nanoparticles such as size, percentage of dextran coating, stability in solution, crystallinity, and magnetic properties were evaluated. The simultaneous semi-two-step method injected the reducing agent and the dextran solution into the reaction vessel at the same time. This method resulted in the greatest batch-to-batch reproducibility of nanoparticle properties and the least variation in nanoparticles synthesized in the same batch. The two-step method resulted in the greatest variation of the characteristics examined between batches. The one-step method was synthesized with both five grams and one gram of dextran to investigate the effects of solution viscosity on the resulting nanoparticle characteristics. The one-step method with five grams of dextran resulted in nanoparticles with significantly smaller crystal sizes (5.4 ± 1.9 nm) and lower specific adsorption rate (SAR) values (138.4 ± 13.6 W/g) in an alternating magnetic field (58 kA/m, 292 kHz). However, this method resulted in nanoparticles that were very stable in PBS over 12 hours, which is most likely due to the greater dextran coating (60.0 ± 2.7 weight percent). For comparison, the simultaneous semi-two-step method generated nanoparticles 179.2 ± 18.3 nm in diameter (crystal size 12.1 ± 0.2 nm) containing 18.3 ± 1.2 weight percent dextran with a SAR value of 321.1 ± 137.3 W/g.
The metamorphosis of heterometallic trinuclear antiferromagnetic complexes into nano-sized superparamagnetic spinels
Vasylenko IV, Gavrylenko KS, Il'yin VG, Golub V, Goloverda G, Kolesnichenko V, Addison AW and Pavlishchuk VV
Thermal decomposition of the trinuclear heterometallic oxoacetates [Fe(2)M(μ(3)-O)(CH(3)COO)(6)(H(2)O)(3)] has been used as a single-precursor method for synthesis of the spinel-structured ternary oxides MFe(2)O(4) (M = Mn(II), Co(II), and Ni(II)). This facile process occurring at 320 °C results in the formation of nanocrystalline, (7-20 nm) highly pure stoichiometric ferrites in quantitative yield. The magnetic properties of these nanoparticulate ferrites were studied in the 10-300 K temperature range, revealing superparamagnetic behaviour for the Ni and Mn particles and ferromagnetic behavior for the Co ones at room temperature. Their blocking temperatures follow the order: CoFe(2)O(4) > MnFe(2)O(4) > NiFe(2)O(4).