Fourier Transform Infrared Spectroscopy Spectra Research Articles

Exploring the effects of silver nanoparticle addition on the properties of paraffin wax phase change material

Ability of phase change materials (PCMs) to store and release significant amount of energy during phase transition has attracted a lot of attention in recent years. However, low thermal characteristics of pure PCMs has been a major limitation in their application for thermal energy storage (TES) systems. In this study, thermal properties of paraffin wax A46 (PW-A46) based composites with the addition of silver nanoparticles (Ag NPs) have been investigated. PW-A46 was chosen as the PCM due to its high latent heat of fusion and low cost, while Ag NPs are known for their high thermal conductivity and have been utilized in various composites to improve thermal properties. Ag NPs were added to the paraffin wax at three different weight percentages of 0.3, 0.5, and 0.7 weight percent (wt.%), and composites were prepared using an ultrasonic probe sonicator. Fourier-transform infrared spectroscopy (FTIR) has been done to study chemical bonding and interactions between paraffin and Ag NPs. No new peaks were observed in the FTIR spectra, indicating that addition of Ag NPs did not cause any significant changes in chemical structure of PW-A46. Thermogravimetric analysis (TGA) results showed that composites were stable up to 230°C, indicating their potential for high-temperature thermal energy storage (TES) applications. UV-Vis results demonstrated a 77% increase in the absorbance of the 0.7 wt.% of AgNPs with A46-PW (PW/0.7Ag) composite. Overall, the results suggested that addition of Ag NPs to paraffin wax can improve the optical and thermal characteristics of pure PCM for potential applications.

Effect of different etching times on the structural, morphological, electrical, and antimicrobial properties of mesoporous silicon

The present work focuses on the structural, morphological, electrical characteristics, and antibacterial activity of mesoporous silicon (PS) against S. aureus and E. coli. We depict the structural and antimicrobial activity of PS as a result of different etching times (10.0, 20.0, 30.0, 40.0, 50.0, and 60.0 min) with a current density of 100 mA/cm2. The structural and morphological characteristics of synthesized PS have been examined with Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). FTIR spectra have been used to confirmed the Si–O, Si–O–Si bond and the adsorption on the surface of PS nanoparticles. The formation of pores on the c-Si wafer results in an analysis of a photoluminescence (PL) band at 712 nm, which changes with etching time in a process similar to current density. The correlation exist among etching times and the ideality factor (η) and barrier height (фb). Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria showed enhanced antimicrobial activity against the PS nanoparticles. The synthesized of PS has been shown with good electrical and antimicrobial activities.

Comparative electrochemical properties of polyaniline/carbon quantum dots nanocomposites modified screen-printed carbon and gold electrodes

In this study, carbon quantum dots (Cdots) synthesized from a pencil graphite precursor using a bottom-up method were incorporated into polyaniline (PANI) to form Cdots-PANI nanocomposite. Cdots, PANI and Cdots-PANI nanocomposites were characterized using the Fourier-Transform infrared spectroscopy (FT-IR), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The FT-IR spectra of graphene and Cdots show the emergence of a peak at 3500 cm−1, which was initially absent in graphene, after the formation of Cdots, among other peaks. The peak at 3500 cm−1 and the stretching vibration at 1647 cm−1 suggest the presence of –OH and C=C in the Cdots. The FT-IR spectra of PANI/Cdots and PANI show that the peaks in PANI shifted to higher wavenumbers after composite formation. Similarly, the UV–visible spectra of the PANI/Cdots composite revealed a hypsochromic shift of the characteristic PANI peaks at 320 and 600 nm to 300 and 560 nm, respectively. Electrochemical characterization of Cdots, PANI and Cdots-PANI nanocomposites was done with screen-printed carbon electrodes (SPCE) and screen-printed gold electrodes (SPAuE) modified with the nanomaterials and the nanocomposites. The electrochemical properties of the as-synthesized nanomaterials and the nanocomposite were investigated with Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in 10 mM K3[Fe(CN)6] solution using the bare screen-printed electrodes and the modified electrodes. The modified electrodes gave higher anodic peak current (Ipa) responses and lower charge transfer resistance (Rct) values in the redox probe than the bare electrodes. The SPCE-Cdots-PANI nanocomposite-modified electrode exhibited better redox potentials, faster electron transfer kinetics, larger surface area, and greater stability than the bare electrodes and the other modified electrodes. The outstanding electrochemical properties of SPCE-Cdots/PANI underscores its potentials as a sensitive electrochemical sensor for a wide range of analytes.

Unraveling the Potential of Organic Oregano and Tarragon Essential Oils: Profiling Composition, FT-IR and Bioactivities

Oregano and tarragon are widely cultivated culinary herbs used for food seasoning, having familiar characteristic aromas appreciated by the wide public. The aim of this research was to characterize essential oils (EOs) from locally sourced organic oregano and tarragon (Cluj, Romania) and study their bioactivity potential. Results showed that oregano EO had a sesquiterpene dominant profile responsible for strong bands between 2800 and 3000 cm−1 on the Fourier transform infrared spectroscopy (FT-IR) spectrum and a composition consistent with reports from similar climatic regions. The tarragon EO profile was defined by phenylpropanoids responsible for the strong sharp peaks between 1000 and 1600 cm−1 on the FT-IR spectrum. In oregano EO, 22 compounds were identified with β-caryophyllene as a major constituent. In tarragon EO, 20 compounds were identified with eugenol as a major constituent. Oregano EO had a stronger antibacterial effect against both Gram-negative and Gram-positive bacterial strains, while tarragon EO had a slightly stronger cytotoxic effect on three types of cancer cell lines tested (skin melanoma, prostate carcinoma, and colorectal adenocarcinoma). It was concluded that, given the fact that a sufficient supply of high-quality plant material can be available for EO extraction, culinary herbs can become reliable candidates for many industries without the risk of discontinued supply. Therefore, research aiming to widen their potential applications is welcome and worth pursuing.

An FTIR-based model for the diagenetic alteration of archaeological bones

Bones and teeth from archaeological records are direct evidence of past individuals and they represent valuable archives for palaeo-anthropological and palaeoenvironmental studies. However, pristine information may be obliterated by the diagenetic alteration of bone specimens. Thus, defining in detail their preservation state is fundamental to assess the potential of extracting information about the past life of the individual, as well as to investigate the palaeo-environment at the burial site. For this reason, we have selected a set of archaeological samples (petrous bones and tooth roots) of different origin and chronology that have experienced diverse environmental and burial conditions, from arid and semi-arid to temperate regions in a time span from prehistoric to fresh bones. Thus, the selected samples underwent a variety of diagenetic processes, resulting in different types and extent of alteration patterns. Here we have applied a minimally-invasive sampling strategy and an analytical protocol based on Fourier transform infrared spectroscopy (FTIR) in order to ensure the investigation of a statistically significant set of samples. We provide a method to describe and quantify the changes in the physico-chemical properties of both the organic and inorganic constituents of bones, by establishing a set of parameters calculated from the FTIR spectra and evaluating their sensitivity in describing the alteration types and extent in bone specimens. Through FTIR spectral analysis, we have defined the most suitable parameters to effectively describe the alteration degree of bone specimens. Notably, the results have shown that, despite the complexity of multifactorial diagenetic processes, their measurable effects on differently altered bones can be described by a common mechanism. This indicates a progressive loss of collagen which is paralleled to the recrystallization of bioapatite and the loss of structural carbonate, regardless of the origin and chronology of the specimens. Thus, here we propose an FTIR-based model for bone diagenesis of general validity, highlighting that distinct diagenetic processes affecting the archaeological bones have acted according to common alteration mechanisms.

Comparative investigation of low and high pelletize pressure for (Ag)x/CuTl-1223 nanoparticles-superconductor composites

This article experimentally investigates the impact of silver (Ag) nano-particles inclusion and high pelletized pressure on the structural, morphological, and electrical properties of Cu0.5Tl0.5Ba2Ca2Cu3O10−δ (noted CuTl-1223) bulk system. The nano-(Ag) x /CuTl-1223 composites were synthesized using a two-step solid-state reaction process with added amount of Ag nano-particles ranging from 0 to 2.0 wt% of the total mass. These nano-composites were produced at both low and high pelletize pressure of 0.202 GPa. All prepared samples were characterized using valuable techniques such as X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), and dc-resistivity measurement at low as well as high pelletized pressure, respectively. The structural investigation via the XRD technique indicated that Ag NPs did not affect the CuTl-1223 tetragonal structure, confirmed that Ag nano-particles were settled across the grain boundaries. SEM examination revealed a fine distribution of nano-sized silver (Ag) NPs among the CuTl-1223 grains, as well as improved weak-links and density of void/pores. The position of distinct vibrational oxygen modes in FTIR spectra showed no substantial alteration, indicating that the structural nature of the host CuTl-1223 phase was preserved. The electrical properties were studied using the four-point probe technique, and the activation energy were determined using Arrhenius law. The results of measurements showed that pelletization pressure of 0.202 GPa have an impact on the critical temperature of (Ag) x /CuTl-1223 composites. The superconducting critical temperature was enhanced from 99 K to 107 K at high-pressure of pelletization (0.202 GPa) as compared to low pressure, with = 0 ∼ 2.0 wt nano-particles addition to the host CuTl-1223 phase.

Molecular identification of keratinophilic fungi associated with hair scalp and antifungal activity of green-synthesis zinc oxide nanoparticles.

A diverse population of fungi colonizes human hair and skin due to millions of years of functional integration and mutual adaptation. The human body, with its fungal communities, forms a complex entity. Microbial imbalance is promoted by instabilities in the host-mycobiota interaction system, which can be related to the development of various diseases. By morphological and molecular identification, 15 genera comprising 24 species were isolated from 18 scalp samples collected from girls. Yeast-like structures were the most common species in this study; they were recovered from six samples (33.3%). They were represented by five species: Arachniotus ruber; Cosmospora aurantiicola; Cutaneotrichosporon oleaginosum; Geotrichum candidum and Suhomyces tanzawaensis. For the synthesis of zinc oxide nanoparticles (ZnO NPs), an aqueous extract of Zingiber officinale was utilized as a reducing and capping agent. The prepared NPs tested by X-ray diffraction, they had a hexagonal wurtzite structure. Most of the ZnO NPs were spherical, and their diameter was about 38.9 nm using a transmission electron microscope. ZnO NPs of the Fourier-transform infrared spectroscopy spectra were recorded in the range of 400-4000 cm-1. UV-visible diffuse reflectance spectroscopy showed the 200-800 nm wavelength range. ZnO NPs showed the highest activity against Ambrosiella hartigii Ambh2; Cladosporium cladosporioides Cladcl12; C. cf. cucumerinum Cladcu13; S. tanzawaensis Suht34, with minimal inhibitory concentrations 1.25 × 103 µg/mL on the four isolates.

Evaluating the Prebiotic Properties of Agar Oligosaccharides Obtained from the Red Alga Gracilaria fisheri via Enzymatic Hydrolysis.

Currently, the demand in the food market for oligosaccharides with biological activities is rapidly increasing. In this study, agar polysaccharides from Gracilaria fisheri were treated with β-agarases and hydrolyzed to agar oligosaccharides (AOSs). High-performance anion-exchange chromatography/pulsed amperometric detection (HPAEC-PAD), Fourier-transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC), were employed to analyze the chemical characteristics of AOSs. The FT-IR spectra revealed that the enzymatic hydrolysis had no effect on specific functional groups in the AOS molecule. To investigate the prebiotic and pathogen inhibitory effects of AOSs, the influence of AOSs on the growth of three probiotic and two pathogenic bacteria was examined. The gastrointestinal tolerance of probiotics in the presence of AOSs was also investigated. AOSs enhanced the growth of Lactobacillus plantarum by 254%, and inhibited the growth of Bacillus cereus by 32.80%, and Escherichia coli by 58.94%. The highest survival rates of L. plantarum and L. acidophilus were maintained by AOSs in the presence of α-amylase and HCl under simulated gastrointestinal conditions. This study demonstrates that AOSs from G. fisheri exhibit potential as a prebiotic additive in foods.

Study on photoluminescence of integrated nano-calcium carbonate (CaCO3) enhanced with dysprosium (Dy) doped calcium borophosphate (CBP) phosphor

Purpose There is a strong inducement to develop new inorganic materials to substitute the current industrial pigments, which are known for their poor ultraviolet absorbent and low photoluminescence (PL) properties. The purpose of this paper is to invent a better rare-earth-based pigment material as a spectral modifier with good luminescence properties to enhance the spectral response for photovoltaic panel application. Design/methodology/approach Different phosphor samples made of nano-calcium carbonate (CaCO3) with varied wt.% of the dopant Dysprosium doped calcium borophosphate (CBP/Dy) as (W0 – 0%, W1 – 3,85%, W2 – 7.41%, W3 –10.71% and W4 –13.79%) were prepared via the solid-state diffusion method at 600 °C for 6 h using a muffle furnace. The structural, morphological and luminescence properties of the CaCO3:CBP/Dy powder samples were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and PL test. Findings The XRD, SEM and FTIR results verified the crystalline formation, morphological behaviour and vibration bonds of synthesized CBP/Dy-doped CaCO3 powder samples. XRD pattern revealed that the synthesized powder samples exhibit crystalline structured materials, and SEM results showed irregular shape and porous-like structured morphologies. FTIR spectrum shows prominent bands at 712, 874 and 1,404 cm−1, corresponding to asymmetric stretching vibrations of CO32− groups and out-of-plane bending. PL characterization of CBP/Dy-doped CaCO3 (sample W) shows emission at 427 nm (λmax) under the excitation of 358 nm. The intensity of PL emission spectra drops due to the concentration quenching effect, while the maximum PL intensity is observed in the W3 phosphor powder system. Research limitations/implications This phosphor powder is expected to find out the potential application such as a spectral modifier which is applied to match the energy of photons with solar cell bandgap to improve spectral absorption and lead to better efficiency. Originality/value The introduction of a nano-CaCO3:CBP/Dy hybrid powder system with good luminescence properties to be used as spectral modifiers for solar cell application has been synthesized in the lab, which is a novel attempt.

Upgrading MnO2@CuO with GO as a superior heterogeneous nanocatalyst for transesterification of dairy waste oils to biodiesel through electrolysis procedure

In this research, the electrolysis procedure was employed to synthesize biodiesel from dairy waste oil (DWO) utilizing MnO2@CuO and MnO2@CuO@GO as novel heterogeneous nanocatalysts. The structural attributes of MnO2@CuO and MnO2@CuO@GO nanocatalysts were scrutinized utilizing Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), Mapping, Energy Dispersive X-ray (EDX), Transmission Electron Microscopy (TEM), Temperature-Programmed Desorption (CO2/TPD), Raman, X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) analyses. Further, Proton Nuclear Magnetic Resonance (H NMR), Gas Chromatography–Mass Spectrometry (GC-MS), and FTIR spectra were utilized to characterize the chemical structure of biodiesel and DWO. According to the Box-Behnken Design statistical method, the highest biodiesel yield utilizing MnO2@CuO and MnO2@CuO@GO nanocatalysts was 94.15 and 98.07 %, respectively, which were obtained after 52.64 and 49.3 min, respectively. According to the results, MnO2@CuO@GO has a higher ability to generate biodiesel compared to MnO2@CuO. After 7 consecutive reuse cycles, the yield of biodiesel using MnO2@CuO and MnO2@CuO@GO nanocatalysts was 80.14 and 90.77 %, respectively, demonstrating that MnO2@CuO@GO is much more stable than MnO2@CuO. The kinetics of biodiesel generation showed that the reaction between DWO and methanol in the presence of MnO2@CuO@rGO is non-spontaneous and endothermic (ΔHo = 47.54 kJ/mol). In general, MnO2@CuO@GO, because of its easy synthesis, high biodiesel efficiency, and remarkable stability, is considered as a promising catalyst for industrial applications.

Room temperature sensing of ammonia and formaldehyde gases through novel anisotype heterojunction of p-Co3O4/n-Gd0.1Ce0.9O2-δ as highly responsive and stable sensors

The development of the room temperature (RT) gas sensors is absolute need. Hydrothermally and sol-gel derived Co3O4 and Gd0.1Ce0.9O2-δ (GDC) were used to fabricate the novel heterostructures in the ratio of 1:1 Co3O4/GDC, 2:1 Co3O4/GDC and 1:2 Co3O4/GDC. These samples were scientifically analysed through X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive X-ray (EDX) spectra, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman, UV–Vis-Diffuse reflectance spectra (DRS) and photoluminescence (PL). XRD, XPS together with FTIR and Raman spectra are the testimonial of the formation of Co3O4, GDC and their heterostructures. Interestingly, the performed gas sensing studies conclusively disclose that these sensors have adequate sensitivity to detect the tested gases at RT. Furthermore, O2− species played crucial role than O2− and O− in chemisorption and gas sensing mechanism. Additionally, 2:1 Co3O4/GDC and 1:2 Co3O4/GDC exhibited an enormous selectivity and highly responsive towards the detection of formaldehyde (CH2O) and ammonia (NH3), respectively. 2:1 Co3O4/GDC/1:2 Co3O4/GDC offered the high response (S) of 106.59/83.52 for CH2O/NH3 gas. In fact, the formation of anisotype p-n/n-p rather than isotype p-p/n-n junctions in 2:1 Co3O4/GDC and 1:2 Co3O4/GDC endowed these two heterostructures to exhibit quick response even at low ppm of selected gases. The outcome of this work might provide strategy for the design of novel sensing materials to detect multiple gases.

Performance evaluation of surface-modified silica nanoparticles for enhanced oil recovery in carbonate reservoirs

The purpose was to prepare a (3-glycidoxypropyl)-trimethoxysilane (GPTMS)-SiO2 nanofluid and analyze the effect of nanofluid injection on carbonate reservoirs. GPTMS-modified silica nanoparticles (SNPs) were investigated by Fourier transform infrared spectroscopy (FTIR) and elemental analysis. FTIR spectra of C-H stretching vibrations at 2950 cm−1, indicating silica surface modification with GPTMS, were observed when the GPTMS in the feed was greater than 0.7 mmol/g. Further, a stable nanofluid was obtained when the amount of grafted silane was close to 0.73 mmol/g, the theoretical maximum amount of grafted silanes. To evaluate the performance of surface-modified SNPs for enhanced oil recovery in carbonate reservoirs, wettability alteration tests comprising flotation test and contact angle measurements using powder and plug samples of carbonates, respectively, were performed with different SNP concentrations. Powder samples were successfully changed from oil-wet to water-wet, and the contact angle of the plug sample decreased by up to 62.8% as a result of the reaction of the nanofluid; however, it did not reduce interfacial tension (IFT) as effectively as IFT reducer additives. A coreflooding test was conducted to determine the effective parameters of the enhanced oil recovery with the GPTMS-nanofluid, such as SNP concentration, injection rate, and rock properties. The nanofluid injection increased oil recovery by approximately 20% compared to conventional waterflooding through incremental oil recovery, mainly attributed to wettability alteration. Therefore, we expect the nanofluid to dramatically increase the oil recovery in strongly oil-wet carbonate reservoirs under high-salinity conditions.

Designing protein-polysaccharides based bioactive copolymeric network by supra-molecular interactions for sustained drug delivery

Keeping in view recent advancements in designing biomaterials from bioactive polysaccharides, the present work deals with the design of protein (gelatin)-polysaccharide (tragacanth gum) based bioactive copolymeric network by supramolecular interactions and covalent linkage for sustained drug delivery (DD) applications. The network copolymeric structure was characterized by field emission-scanning electron micrographs (FE-SEM), electron dispersion X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). FESEM and XRD analyses revealed the heterogeneous morphology of copolymers with an amorphous nature. 13C NMR and FTIR spectra demonstrated the incorporation of poly(acrylamide) (AAm) into network structure by copolymerization reaction. Diffusion of anticancer drug 5-flurouracil (5-FU) occurred in a sustained manner with the Fickian mechanism and was best fitted in first order kinetic model. Polymer-blood interactions revealed the non-hemolytic character of hydrogels. An antioxidant assay evaluated their antioxidant property (26.61 ± 0.85 % of free radical scavenging). Copolymers exhibited mucoadhesiveness during polymer-mucous membrane interactions and required 113.33 ± 5.68 mN detachment forces. Furthermore, the combination of polysaccharide-gelatin has enhanced supramolecular interactions and improved physiological and biomedical properties of network hydrogels. Overall, these properties revealed the suitability of copolymeric hydrogels for drug delivery applications.

Preparation, Characterization, Photochromic Properties, and Mechanism of PMoA/ZnO/PVP Composite Film.

A novel photochromic heteropolyacid-based composite film consisting of phosphomolybdic acid (PMoA), ZnO, and polyvinylpyrrolidone (PVP) was fabricated by a sol-gel process. The microstructure and photochromic properties of the PMoA/ZnO/PVP were characterized via Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectroscopy (UV-Vis). The FTIR spectra showed that the basic structures of ZnO and PVP, and the Keggin structure of PMoA in the PMoA/ZnO/PVP composite film, had not been destroyed during the preparation. The TEM images demonstrated that ZnO presented a rod-like structure, while PMoA was spherical, and many PMoA balls adhered to the surface of the ZnO rods. The XPS spectra of Mo 3d indicated that the valency of Mo atoms in the PMoA/ZnO/PVP was changed by visible light exposure. After visible light irradiation, the PMoA/ZnO/PVP varied from slight yellow to blue, while undergoing an opposite color change upon heating. The discoloration mechanism of the PMoA/ZnO/PVP was consistent with the photoelectron transfer mechanism.

Antibacterial activity of biosynthesized zinc oxide nanoparticles using Kombucha extract

Antibacterial resistance is a growing global vital medical problem when the innovation and development of new antibiotics are dwindling. Different nanomaterials were synthesized and developed as safe and effective alternative antimicrobial agents. The current study highlights the effect of the antibacterial activity of newly biosynthesized zinc oxide nanoparticles (ZnO NPs) obtained from Kombucha extract. Production of ZnO NPs was optimized and the synthesized nanoparticles were characterized using UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Zeta potential and transmission electron microscope (TEM) analysis. The optimum conditions for ZnO NPs production were at temperature 30 °C, pH 9 and 25 mM of Zn(NO3)2.6H2O. The ZnO NPs biosynthesis was detected in the extract within 24 h. at 35 °C in dark conditions. The XRD pattern displayed 100, 101, 110, and 103 crystal planes. FTIR spectrum showed bands of 1° and 2° amines at 2922.6 cm−1 and a stretching vibration band of vinyl at 1657.5 cm−1. In addition, the results confirmed the positive charge (19 ± 3 mV) and crystalline nature of spherical-shaped ZnO NPs with an average size of 23 ± 1.5 nm. The antibacterial activity of ZnO NPs was tested against different American-type culture collection strains. ZnO NPs exhibited minimum inhibition concentration (MIC) values of 25 µg/ml against Escherichia coli ATCC25922, 30 µg/ml against Staphylococcus aureus ATCC25923 and Pseudomonas aeruginosa ATCC27853, 35 µg/ml against Serratia liquefaciens OQ071699.1 and S. saprophyticus OQ071703.1 and 40 µg/ml against Lysinibacillus fusiformis OQ071701.1 and Klebsiella pneumoniae ATCC33495. Ultrastructure TEM study of the treated bacteria by MIC of ZnO NPs confirmed their highly toxic action on the bacterial cell wall, resulting in bacterial cell membrane rupture. Treated bacteria appeared as extensively damaged cells with the formation of vacuoles and lipids. The provided approach of ZnO NPs in combination with Kombucha SCOBY has a promising future in overcoming bacterial resistance problems in place of using antibiotics.

Thermo- and pH-responsive targeted lipid-coated mesoporous nano silica platform for dual delivery of paclitaxel and gemcitabine to overcome HER2-positive breast cancer

In the current study, a new monoclonal antibody conjugated dual stimuli lipid-coated mesoporous silica nanoparticles (L-MSNs) platform was developed and investigated for specific co-delivery of the paclitaxel (PTX) and gemcitabine (Gem) to cancer cells and preventing their side effects during the treatment process. First, MSNs were synthesized and then coated with as-prepared pH-, and thermo-sensitive niosomes to produce L-MSNs. For this aim, Dipalmitoylphosphatidylcholine (DPPC) was used to create thermo-sensitivity, and 1, 2-Distearoyl-sn-glycerol-3-phosphoethanolamine -Citraconic Anhydride-Polyethylene Glycol (DSPE-CA-PEG) polymers were prepared and incorporated to the lipid layer for creation of pH-sensitivity. In the next step, trastuzumab as a monoclonal antibody (mAb) was conjugated to the maleimide groups of the 1, 2-Distearoyl-sn-glycerol-3-phosphoethanolamine DSPE-polyethylene glycol (PEG)-maleimide agents in the lipid bilayer via a disulfide bond. Dynamic light scattering (DLS) and zeta potential measurements, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and scanning electron microscopy (SEM) analyses were utilized to characterize the synthesized particles before and after surface modification. The encapsulation efficiency (EE%) and loading efficiency (LE%) of the particles were also evaluated. Additionally, the drug release study and MTT assay were done to evaluate the bioactivity potential of the fabricated platforms. The results of DLS and zeta potential measurements revealed an average size of 200 nm and a neutral zeta potential of about −1 mV for mAb-L-MSNs. Also, the FTIR spectra confirmed the formation of mAb-L-MSNs. Moreover, SEM analysis showed spherical-shaped MSNs with amorphous structure confirmed by XRD analysis, and BET test revealed ∼ 820 m2/g specific surface area and pore about 5 nm in size. The values of EE% and LE% of PTX were 90.3 % and 26.7 %, while these values for GEM were 89.5 % and 38.8 % in the co-loaded form, respectively. The thermo-pH-sensitivity examination showed approximately 500 nm of size increase after the change of pH and temperature from 7.4 and 37˚C to 5 and 42˚C. The release profile showed a pH-, and thermo-dependence manner, which led to about 89 % and 95 % of PTX and GEM released from the co-loaded platform at a pH of 5 and 42 °C while these values were 31.1 % and 32.2 % at pH of 7.4 and 37˚C, respectively. MTT assay data presented that when the mAb-L-co-loaded-MSNs platform containing 250 µg/mL drug was used, about 92 % of cells died in human epidermal receptors (HER2)-positive breast cancer cells (SKBR3), while just about 4 % of HER2-negative normal cells were killed. However, the growth inhibition rate of SKBR3 cells was caused by empty-mAb-L-MSNs, pure PTX and GEM combination were 9 % and 87 %, respectively. Moreover, the half inhibitory concentration (IC50) of the pure PTX, pure GEM, and mAb-coloaded-L-MSNs were 33, 17.6, and 6.5 µg/mL. The synergic effect of co-encapsulation of PTX and GEM in addition to trastuzumab conjugated L-MSNs was confirmed by a combinational index (CI) of 0.34. Therefore, this strategy leads to specific targeted drug delivery to cancer cells using a key-lock interaction between the trastuzumab and HER-2 receptors on the cancer cell membrane which stimuli the endocytosis of the particles to the cells followed by the destruction of the lipid layer in the acidic pH and the temperature of the lysosome, leading to enhanced release of PTX and GEM (pH of 5 and 42˚C). So, this platform can be considered a suitable carrier for cancer treatment.

Study of the influence of calcium fluoride on the bioactivity of boron-based glass

This work aimed to evaluate the influence of CaF2 addition in the bioactivity of the samples. The system 60B2O3-4P2O5-18Na2O-xCaF2-(18-xCaO), with x= 0, 5 and 10 wt% was synthetized by melt-quenching method. The in vitro bioactivity of the glasses was investigated by X-ray diffractogram (XRD), Raman, Fourier transform infrared spectroscopy (FTIR) and pH after immersion in SBF solution during 28 days. Results of pH presented an increase after 24 hours of soaking in SBF, which contributes to the dissolution of the external layer of the glass and precipitation of apatite. Hydroxyapatite and fluorapatite formation was confirmed by XRD patterns, Raman and FTIR spectra, confirming the bioactivity of the samples. Cytotoxicity tests were performed on osteoblastic cells. All the samples presented cytotoxicity smaller than 10%, and induced the osteoblast proliferation, indicating a good cytocompatibility and good cell viability. Therefore, the glasses have potential to be applied in biomedical applications, such as odontology and tissue engineering.

Preparation and characterization of zein-based core-shell nanoparticles for encapsulation and delivery of hydrophobic nutrient molecules: Enhancing environmental stress resistance and antioxidant activity

A simple reverse solvent co-precipitation method was designed to prepare zein/debranched oxidized starch core-shell composite nanoparticles. Studies have shown that the composite nanoparticles have good stability and the ability to protect resveratrol from chemical degradation during long-term storage, pasteurization, and ultraviolet irradiation. The encapsulation rate of resveratrol in composite nanoparticles (81.15%) was significantly higher than that of pure protein nanoparticles (47.15%). The results of FT-IR (fourier transform infrared spectroscopy), circular dichroism, and fluorescence spectra show that hydrogen bonding, hydrophobic interaction, and electrostatic interaction exist in the composite nanoparticles. Under pasteurization conditions, ultraviolet radiation, and two weeks of room-temperature storage, the composite nanoparticles can better maintain the biological activity of nutrient molecules. Moreover, the particles can maintain stability in different pH and ionic strength environments and gradually degrade and release active molecules in the intestinal tract in vitro in the simulated gastrointestinal environment. These results show that zein/debranched oxidized starch nanoparticles (ZDNPs) have great potential for application in the fields of functional drinks, food, and biomedicine-related delivery.

Effect of physical and chemical activation methods on the structure, optical absorbance, band gap and urbach energy of porous activated carbon

In this study, activated carbon was synthesized using the almond shell and palm kernel by physical activation with water vapor and chemical activation with phosphoric acid (H3PO4) methods. Then, the structural and optical properties of the activated carbons were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and UV–Vis spectroscopy. The SEM images showed that in the raw sample of hard almond shell and palm kernel, there is no porosity and pores, but in the activated carbon samples, porosity and structural defects were clearly observed. The XRD patterns showed that porous and amorphous structure was formed in all samples synthesized with physical and chemical activation. The results of FTIR spectra of activated carbons showed that there are carbon functional groups in all samples. The optical absorption coefficient (α) of the activated carbon with physical and chemical activation methods was obtained in order of 105–106. The band gap measurement of porous nanostructures showed that the activated carbon synthesized with chemical and physical activation methods have energy gap (Eg) in region = 2.80 to 3.15 eV and urbach energy (EU) in region = 120 to 210 meV.

PREPARATION, CHARACTERISATION, EVALUATION AND DFT ANALYSIS OF CILNIDIPINE-L-PHENYLALANINE COCRYSTAL

Objective: The objective of this study was to prepare, characterise and evaluate pharmaceutical cocrystals of Cilnidipine using L-phenylalanine as the coformer to enhance the aqueous solubility of Cilnidipine. It was also proposed to study the mechanism of cocrystal formation based on Density Functional Theory (DFT) using Gaussian software. Methods: To overcome the limitation of poor aqueous solubility of Cilnidipine, a 1:1 pharmaceutical cocrystal of Cilnidipine was prepared using L-phenylalanine as the coformer by liquid assisted grinding (LAG) technique. The resultant cocrystals were characterised by Fourier transform-infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and field emission scanning electron microscopy (FE-SEM). They were evaluated for their saturation solubility in water. The mechanism of cocrystal formation was studied at the DFT level of theory. Results: The band broadening of the–NH and–NO peaks in FTIR spectra of Cilnidipine indicated the formation of hydrogen bonds in the prepared cocrystals. A single sharp melting endotherm at 218.40 °C in the DSC curve confirmed the formation of cocrystals. The appearance of new peaks in the PXRD pattern of the prepared cocrystals showed the formation of a new crystalline phase. FE-SEM analysis also confirmed the above findings. The prepared cocrystals exhibited 3.31 folds enhancement in saturation solubility. The DFT analysis showed the formation of intrmolecular hydrogen bonding between the–NO of Cilnidipine and–NH of L-phenylalanine. Conclusion: The present study demonstrated a successful approach for enhancing the solubility of poorly water-soluble drug Cilnidipine by cocrystallisation technique using L-phenylalanine as the coformer.