Ultraviolet-visible Absorption Spectroscopy Research Articles

Supramolecular phosphorescent assemblies based on cucurbit[8]uril and bromophenylpyridine derivatives for dazomet recognition.

A bromophenylpyridine derivative (N1) was designed, synthesized, and the molecule was incorporated into the cavity of the cucurbit[8]uril (Q[8]) as a guest to form a 2:1 host-guest complex. This complex demonstrates good room temperature phosphorescence (RTP) properties in aqueous solution. The host-guest interaction and optical properties of N1@Q[8] in aqueous solution were studied by means of 1H NMR, ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, phosphorescence spectroscopy, scanning electron microscopy and inverted fluorescence microscopy. The results show that the bromophenyl part of the guest molecule enters the cavity of Q[8], while the other part of N1 remains outside the cavity, resulting in a 2:1 supramolecular structure. This assembly exhibits specific recognition of dazomet on the phosphorescence spectrum with a detection limit of 8.8329×10-7mol·L-1. Collectively, this finding opens up a new possibility for the potential application of room temperature phosphorescent materials in analytical detection.

Preparation of soluble starch/zinc oxide nanocomposites by solid-phase reaction and study of their antibacterial properties.

Soluble starch/zinc oxide nanocomposites could be promising candidates for eco-friendly antimicrobial, food packaging, and a wide range of other utilization. In order to find a new way for the preparation of this kind of nanocomposites, an efficient and energy-saving reaction for the synthesis of soluble starch/zinc oxide nanocomposites has been investigated. The reaction was implemented in a solid state at room temperature without post-reaction calcination. In this process, the starting materials were ZnSO4·7H2O and KOH, while KCl served as the matrix and soluble starch was used as the surfactant. The prepared nanocomposites were characterized by Fourier infrared spectroscopy, X-ray diffraction spectrum, transmission electron microscope, scanning electron microscope, dynamic light scattering, and ultraviolet-visible absorbance spectroscopy. In addition, the UV-blocking effect and antimicrobial capability of the prepared nanocomposites were determined. The results showed that the nanocomposites were composed of soluble starch and ZnO nanoparticles. The mean diameter of ZnO nanoparticles was 12 nm. The results also showed that the suspension composed of nanocomposites were superior to that composed of simple zinc oxide nanoparticles in stability and inhibition of Escherichia coli and Staphylococcus aureus.

Structure of Ni(II) Inclusion Complex in Solid/Solution States and the Enhancement of Catalytic Behavior in Electrochemical Hydrogen Production.

In this article, we investigate the encapsulation of K2[Ni(maleonitriledithiolate)2] (1) within a host molecule, β-cyclodextrin (β-CD), via single-crystal X-ray analysis. An inclusion complex, K2{[Ni(maleonitriledithiolate)2]@(β-CD)2} (2), was constructed from 1 and two β-CDs. The anion guest Ni complex included a host cavity, constructed using two β-CDs, and the Ni atom of the anion was located between the two hydrophilic primary rims. Ultraviolet-visible absorption spectroscopy revealed that inclusion complex 2 exhibited a 2:1 (host:guest) stoichiometry in the solution, which is consistent with the result obtained from X-ray crystallography. The association of the host and guest occurred in two steps, and the association constants for the first and second steps were 1.1(7) × 104 and 1.8(5) × 104 mol-1 dm3, respectively. The catalytic behavior of 1 and 2 was investigated for electrochemical hydrogen production in the aqueous solution of an acetate buffer (pH = 4.72). During the catalytic reaction, inclusion complex 2 was observed to have a better catalytic reaction rate than 1. The study findings provide insights into the effects of the encapsulation of guest molecules within host structures.

Biosynthesis, Characterization, and Antibacterial Activity of Gold, Silver, and Bimetallic Nanoparticles Using Annona squamosa L. Leaves.

The utilization of nano-sized drug delivery systems in herbal drug delivery systems has a promising future for improving drug effectiveness and overcoming issues connected with herbal medicine. As a consequence, the use of nanocarriers as novel drug delivery systems for the improvement of traditional medicine is critical to combating infectious diseases globally. In line with this, we herein report the biosynthesis of silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), and bimetallic nanoparticles (BMNPs) as antibacterial agents against pathogenic bacterial strains using Annona squamosa L. leaf extract as a bio-reductant and bio-stabilizing agent. The as-synthesized metal nanoparticles were characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and the dynamic light scattering (DLS) method. The as-synthesized MNPs had an average particle size of 6.98 nm ± 2.86 nm (AgNPs), 21.84 ± 8.72 nm (AuNPs), and 2.05 nm ± 0.76 nm (BMNPs). The as-synthesized AgNPs and BMNPs showed good antibacterial activity against pathogenic bacterial strains of Gram-positive Staphylococcus aureus (ATCC 25923) and Gram-negative Escherichia coli (ATCC 25922). The obtained results offer insight into the development of benign nanoparticles as safe antibacterial agents for antibiotic therapy using Annona squamosa L. leaf extract.

Synthesis and characterization of multi-responsive iron oxide nanoparticles: Evaluation of antibacterial properties and photocatalytic activity

Cape gooseberry (CG) plant leaf extract-mediated iron oxide nanoparticles (CG-IO NPs) were fabricated for antibacterial research. The ideal concentration of the precursor salt, pH (11) of the reaction mixture, reducing agent to precursor salt ratio, and the production time of iron oxide nanoparticles were 5 mM, 9.0, 3:7, and 25 min, respectively. The iron oxide nanoparticles were tested using ultraviolet–visible absorption spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric/differential thermal analysis (TG/DTA), and Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy was used to identify functional groups of the compounds, including the carbonyl, CH, and OH bands that reduced and produced nanoparticles. The size and shape of the synthesized CG-IO NPs were determined by TEM and dynamic light scattering, with the median and mean size of 13.9 nm and 15.8 nm, respectively. The thermal stability of the synthesized CG-IO NPs was assessed using TG/DTA in a nitrogen atmosphere. The elements and oxidation states of the CG-IO NP components were examined by XPS. The luminosity of the CG-IO NP was examined using PL spectroscopy. The synthetic CG-IO NPs exhibited strong antibacterial effects against dangerous bacteria, such as Salmonella enterica (S. entirica), Escherichia coli (E. coli), Streptococcus agalactiae, and Staphylococcus aureus. CG-IO NPs assisted in water reclamation by decomposing Malachite Green dye under solar light irradiation.

Enhanced sulfamethoxazole degradation in aqueous media using a synergistic system with dielectric barrier discharge plasma, biochar-enriched iron concentrate, and persulfate

The synthesis of biochar-based catalysts from bamboo strip biomass waste aligns with the principles of environmental sustainability and recycling. This study focuses on the degradation of sulfamethoxazole (SMX) in a simulated aqueous environment. A composite catalyst (IC–BC) was prepared by impregnating bamboo strip biochar (BC) with iron concentrates (IC). The optimal configuration for the oxidative degradation of SMX was achieved using IC-BC-activated persulfate (PS). The structural, morphological, optical, and electrochemical properties of the IC-BC were thoroughly characterized, revealing its robust stability through repeated cycles. The dielectric barrier discharge (DBD) synergistic IC-BC/PS oxidation system demonstrated an SMX degradation efficiency of 93.33 % in 10 min. Quenching experiments and electron paramagnetic resonance (EPR) spectroscopy identified radicals O•−2, •OH, and SO•−4 radicals as the primary active species involved in the degradation process. Ultraviolet-visible absorption spectroscopy (UV–Vis) confirmed this synergistic effect. Liquid chromatography mass spectrometry (LC-MS) identified four potential SMX degradation pathways. Total Organic Carbon (TOC) elimination efficiency tests and toxicological analyses revealed that the intermediates were significantly less toxic than SMX. These results demonstrate that the DBD/IC-BC/PS system significantly enhances the removal efficiency of SMX, offering excellent environmental protection properties.

Nanoparticle-protein interactions: Spectroscopic probing of the adsorption of serum albumin to graphene oxide‑gold nanocomplexes surfaces

Graphene oxide‑gold nanocomposites (GO-AuNCPs) are promising candidates in nanomedicine. They will inevitably bind with biomolecules such as serum albumin (SA) in the body while they enter the organism. The interaction between GO-AuNCPs and human serum albumin (HSA)/bovine serum albumin (BSA) were investigated by using multispectroscopic methods, elucidating the binding principles through molecular simulations. The results of ultraviolet-visible (UV–vis) absorption spectroscopy and steady-state fluorescence spectroscopy indicated that GO-AuNCPs interacted with HSA/BSA with different degrees of interaction. The binding of GO-AuNCPs and HSA/BSA was a spontaneous endothermic reaction, and the quenching mechanism is static quenching. The binding constant (Ka) value of BSA binding to GO-AuNCPs at the same temperature was greater than that for HSA, indicating a stronger affinity of BSA for GO-AuNCPs. Molecular simulation revealed that the binding sites of GO-AuNCPs on HSA/BSA were located within the slits of the subdomains IB and IIIA, rather than within any known binding regions. This significant finding was validated by using of site markers phenylbutazone (PB) and flufenamic acid (FA). Synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, and circular dichroism (CD) spectroscopy showed that the conformation of HSA/BSA was altered upon the addition of GO-AuNCPs, resulting in slight structural changes of tryptophan and tyrosine residues. Although the secondary structure of HSA/BSA was changed, the α-helix remained dominant. The results provide a theoretical and experimental foundation for developing of safe and effective nanomaterials, which is of great theoretical significance.

Green hydrothermal synthesis of gallic acid carbon dots: characterization and cytotoxic effects on colorectal cancer cell line

Colorectal cancer (CRC) remains a leading cause of cancer-related deaths worldwide, necessitating the development of novel therapeutic approaches. Carbon dots (CDs) have emerged as promising nanoparticles for biomedical applications due to their unique properties. Gallic acid (GA), an anticancer agent, is effective against various tumor types. This study explores the potential of gallic acid-derived carbon dots (GA-CDs) as an innovative anticancer agent against HCT-116 CRC cells, focusing on apoptosis signaling pathways. GA-CDs were synthesized using a one-pot hydrothermal method. Characterization was conducted using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, and ultraviolet-visible (UV-vis) absorption spectroscopy. The cytotoxicity of GA and GA-CDs on HCT-116 cells was evaluated using the MTT assay at various concentrations over 24 and 48 h. Cellular uptake was assessed via fluorescence microscopy, and apoptosis was analyzed using acridine orange/propidium iodide (AO/PI) staining. Total RNA extraction followed by complementary DNA (cDNA) synthesis via reverse transcription-PCR was performed, and real time-PCR (Q-PCR) was conducted to examine the expression of apoptosis-related genes includingCaspase-3,Bax, andBcl-2. Characterization confirmed the successful synthesis of spherical GA-CDs. GA-CDs exhibited dose- and time-dependent cytotoxicity, with IC50 values of 88.55 μg ml-1for GA-CDs and 192.2 μg ml-1for GA after 24 h. Fluorescence microscopy confirmed the efficient uptake of GA-CDs by HCT-116 cells. AO/PI staining showed a significant increase in apoptotic cell numbers after treatment with GA-CDs. Q-PCR analysis revealed overexpression ofCaspase-3 andBaxgenes in GA-CD-treated cells, though no significant changes were observed in the expression ofBcl-2 or theBax/Bcl-2 ratio. GA-CDs demonstrated potent anticancer properties by inducing apoptosis and reducing cell viability in HCT-116 cells. These findings suggest the potential of GA-CDs as a novel therapeutic agent for CRC treatment, warranting further investigation into their mechanism of action andin vivoefficacy.

Synthesis of Photocatalyst Based on WO3 Applying for the Treatment of Tetracycline Antibiotics

In this paper, WO3/g-C3N4 photocatalysts were fabricated by ultrasonic-assisted hydrothermal method at different mole ratios of WO3/g-C3N4. Ultraviolet–visible absorption spectroscopy (UV-Vis DRS) and photoluminescence (PL) results indicated that WO3/g-C3N4 photocatalyst with the WO3/g-C3N4 mole ratio of 1/1 (WC-1) showed visible light absorption ability and prevented electron-hole recombination rate better than WO3, g-C3N4 and other composites. The photocatalytic activities of synthesized photocatalysts were investigated by the photocatalytic oxidation of tetracycline (TC) antibiotics under visible light. The degradation efficiency of TC in aqueous environment by the WC-1 was 79.35% after 180 minutes. This value was higher than those of other materials. The improvement in photocatalytic property of the WO3/g-C3N4 was due to the efficient generation of electrons and holes.

In vitro inhibitory effect of berberine against rotavirus combined with its antioxidant, anti-inflammatory, and cytotoxicity activities.

Although berberine (BBR) is well known as a traditional medicine used in treatment of gastrointestinal diseases, its potent against viral gastroenteritis has not been specifically reported. This study aims to investigate the antiviral activity of BBR against rotavirus and evaluate its cytotoxicity and pharmacological efficacies, including antioxidant and anti-inflammatory activities in vitro. Using ultraviolet-visible absorption spectroscopy, the saturation concentration of BBR was determined as 2261 µg/mL, indicating that BBR is a poor water-soluble compound. The inhibition rate of NO production of BBR solution at a concentration of 238 µg/mL was similar to that of Cardamonin 0.3 µM with a cell viability of 92,46±0.35%, revealing the anti-inflammatory activity of BBR. The cytotoxicity of BBR solution depended on its concentration, whereby the 50% cytotoxicity concentration (CC50) of BBR after 96 h exposure was 664 µg/mL. Investigation of cytopathic effects (CPE) of MA104 cells treated with BBR and BBR-incubated rotavirus indicates that BBR could effectively inhibit the replication of rotavirus. CPEs were not observed in the cells inoculated with rotavirus (100TCID50) which was pre-incubated with BBR for 96 hours at BBR concentration of 283 µg/mL. Therefore, the study provides reliable results to demonstrate the ability of BBR to inhibit the replication of rotavirus.

Development of Heterojunction C-TiO2/g-C3N4 as New Photocatalysts for Degradation of Antibiotics Pollutant in Aquesous Environment

C-TiO2 was effectively hybridized with g-C3N4 in the varies mass ratio of C-TiO2/g-C3N4 (10, 20, 30 và 40%) to highly improve its photocatalytic activity for degradation of tetracycline (TC). The prepared samples were characterized by X-ray diffraction (XRD), Ultraviolet–visible absorption spectroscopy (UV-Vis DRS), Photoluminescence (PL) and Energy dispersive X-ray spectroscopy (EDX). As compared with C-TiO2 and g-C3N4, the decoration of C-TiO2 on g-C3N4 led to formation of C-TiO2/g-C3N4 heterojunction to effectively prevent the charge recombination in each material and exhibit great increases in visible light adsorption. The obtained PL and UV-Vis DRS indecated C-TiO2/g-C3N4 material, which the C-TiO2:g-C3N4 mass ratio was 20% showed the strongest tetracycline degradation efficiency (84.24%). With the further increasing in C-TiO2 content in C-TiO2/g-C3N4, photocatalytic degradation efficiency decreased. This was because the excessed C-TiO2 hindered optical absorption for electron-hole separation of g-C3N4 and the excessed C-TiO2 decorating on the surface g-C3N4 could also act as centers for electron-hole recombination leading to decrease photocatalytic degradation efficiency of the C-TiO2/g-C3N4.

Into the Groove: A Multitechnique Insight into the DNA–Vemurafenib Interaction

This study explores the interaction between Vemurafenib (VEM), a potent BRAF inhibitor, and calf thymus DNA (ctDNA) using a comprehensive array of biophysical and computational techniques. The primary objective is to understand the potential off-target effects of VEM on DNA, given its established role in melanoma therapy targeting the BRAF V600E mutation. The investigation employed methods such as ultraviolet–visible absorption spectroscopy, steady-state fluorescence, circular dichroism, isothermal titration calorimetry, and advanced molecular dynamics simulations. The results indicate that VEM interacts with DNA primarily through a minor groove-binding mechanism, causing minimal structural disruption to the DNA double helix. Viscosity measurements and melting temperature analyses further confirmed this non-intercalative mode of binding. Calorimetry data revealed an exothermic, thermodynamically favorable interaction between VEM and ctDNA, driven by both enthalpic and entropic factors. Finally, computer simulations identified the most probable binding site and mode of VEM within the minor groove of the nucleic acid, providing a molecular basis for the experimental findings.

Dual-targeted TfRA4-DNA1-Ag@AuNPs: An innovative radiosensitizer for enhancing radiotherapy in glioblastoma multiforme

Radiation therapy (RT) is one of the most effective and widely used treatment methods for glioblastoma multiforme (GBM). However, its efficacy is often compromised by the inherent radioresistance of tumor cells, while the restrictive nature of the blood-brain barrier (BBB) specifically impedes the delivery of radiosensitizer. Thus, we constructed and characterized polyethylene glycol (PEG)-functionalized silver-gold core-shell nanoparticles (PSGNPs) targeting both BBB (TfRA4) and GBM (DNA1) (TDSGNPs). Afterwards, studies conducted both in vitro and in vivo were employed to assess the BBB penetration capabilities, abilities of GBM targeting and radiosensitization effect. Transmission electron microscope images of PSGNPs showed a core-shell structure, and the results of ultraviolet-visible absorption spectroscopy and dynamic light scattering displayed that TDSGNPs were successfully constructed with excellent dispersion properties. TDSGNPs could be specifically taken up by U87MG cells and the uptake peaked at 24 h. TDSGNPs combined with RT obviously increased the apoptosis proportion of the cells. It was shown by the in vitro and in vivo investigations that TDSGNPs could target U87MG cells after crossing the BBB, and further study revealed that TDSGNPs showed an uptake peak in the tumor sites after 3 h intravenous injection. The radiosensitization of TDSGNPs was better than that of the nanoparticles modified with single aptamers and the median survival of tumor-bearing mice was greatly extended. This study demonstrated that TDSGNPs could penetrate BBB to target GBM, functioning as a promising radiosensitizer for the targeted therapy of GBM.

The influence of precursor solutions containing an amount of silver bismuth sulfide nanoparticles (AgBiS2 NPs) on the characteristics of CH3NH3PbI3 perovskites solar cells

The utilization of organo-metal halide perovskites as absorbers in thin-film solar cells has garnered considerable interest from the scientific community in recent times. In this study, we present the introduction of silver bismuth sulfide nanoparticles (AgBiS2 NPs) doped into perovskite thin films composed of CH3NH3PbI3 thin film. Our results demonstrate that the perovskites' morphology and structure were significantly improved. The effects of AgBiS2 NPs concentration on the optical, mechanical, and crystallographic properties of CH3NH3PbI3 perovskite thin films were investigated. The findings from the structure investigations revealed that an increase in the concentration of AgBiS2 NPs resulted in a transition from a low-crystalline to a polycrystalline structure of the perovskite thin films. An elevation in the concentration of AgBiS2 NPs from 2 to 8 mg/mL led to the development of perovskite films of superior quality, consisting entirely of PbI3 and CH3NH3. These films exhibited almost impeccable deposition, compactness, and uniformity, and their particle size reached an approximate value of 1.3 μm. Furthermore, an increase in the optical absorption coefficient (∼105 cm−1) in the visible spectrum and subsequent enhancements in photoluminescence (PL) and ultraviolet–visible (UV–Vis) absorption spectroscopy serve as further evidence of the film's enhanced quality. When AgBiS2 NPs are doped into perovskites, the films' quality is significantly improved; they acquire a uniform surface morphology, an exceptional crystal structure, and enhanced light absorption, all of which contribute to accelerated PL quenching and charge transfer. Power conversion efficiency (PCE) was enhanced across all photovoltaic parameters through the use of larger granules in bulk-heterojunction solar cells, as opposed to undoped heterojunction solar cells. The PCE of the perovskite device with CH3NH3PbI3 base is 17.04 % at the optimal concentration of 6 mg/mL AgBiS2 NPs. These findings indicate that the doping of CH3NH3PbI3 perovskite thin films with AgBiS2 NPs is essential for the achievement of high crystallinity, a large particle size, and a high absorption coefficient. These properties are advantageous for the high-power conversion efficiency of solar cell applications.

Preparation and Characterization of Pyramids/Particles NiO/SnO2 Composite for Sorption and Separation of Molybdenum and Zirconium Ions from Some Synthetic Fission Products

AbstractPyramids/particles of NiO/SnO2 composite (NS7) was produced by applying the sol–gel autocombustion method. The produced composite was investigated using different techniques, X-ray diffraction, Fourier-transform infrared, Raman spectroscopy, scanning electron microscope, dynamic light scattering, ultraviolet–visible absorbance spectroscopy, and BET surface area then was applied for the adsorption and separation of molybdenum and zirconium ions from lanthanum, strontium, and cesium. 3D pyramids of NiO and particles of SnO2 are confirmed in the composite with a homogeneous mesoporous structure. The composite has good affinity for zirconium and molybdenum ions with fast kinetics and Qmax of 27.1 and 33.3 mg/g, respectively, low affinity for lanthanum, and negligible affinity for strontium and cesium. The sorption mechanism is physical sorption and endothermic in nature. The adsorbed Zr(IV), Mo(VI), and La(III) ions were separated using the desorption process as the following sequence: First, 95 ± 2% (14.3 ppm) of the loaded La was desorbed by washing with double distilled water. Then 96 ± 2% (41.3 ppm) of the loaded Zr was recovered by 1 M potassium chloride without interfering ions. Finally, 98 ± 2% (42.88 ppm) of Mo is desorbed by 1 M sodium acetate solution. The NS7 composite can be reused five times successfully.

A Dy(III) Coordination Polymer Material as a Dual-Functional Fluorescent Sensor for the Selective Detection of Inorganic Pollutants.

A Dy(III) coordination polymer (CP), [Dy(spasds)(H2O)2]n (1) (Na2Hspasds = 5-(4-sulfophenylazo)salicylic disodium salt), has been synthesized using a hydrothermal method and characterized. 1 features a 2D layered structure, where the spasda3- anions act as pentadentate ligands, adopting carboxylate, sulfonate and phenolate groups to bridge with four Dy centers in η3-μ1: μ2, η2-μ1: μ1, and monodentate coordination modes, respectively. It possesses a unique (4,4)-connected net with a Schläfli symbol of {44·62}{4}2. The luminescence study revealed that 1 exhibited a broad fluorescent emission band at 392 nm. Moreover, the visual blue color has been confirmed by the CIE plot. 1 can serve as a dual-functional luminescent sensor toward Fe3+ and MnO4- through the luminescence quenching effect, with limits of detection (LODs) of 9.30 × 10-7 and 1.19 × 10-6 M, respectively. The LODs are relatively low in comparison with those of the reported CP-based sensors for Fe3+ and MnO4-. In addition, 1 also has high selectivity and remarkable anti-interference ability, as well as good recyclability for at least five cycles. Furthermore, the potential application of the sensor for the detection of Fe3+ and MnO4- was studied through simulated wastewater samples with different concentrations. The possible sensing mechanisms were investigated using Ultraviolet-Visible (UV-Vis) absorption spectroscopy and density functional theory (DFT) calculations. The results revealed that the luminescence turn-off effects toward Fe3+ and MnO4- were caused by competitive absorption and photoinduced electron transfer (PET), and competitive absorption and inner filter effect (IFE), respectively.

New insights on thermal ageing of electrical insulating oils as revealed from photoluminescence and absorption spectroscopy

AbstractRecently, significant efforts have been exerted to replace mineral oil with environmentally friendly oils due to safety and environmental issues. However, there is a need to clarify the physical mechanisms behind the ageing impact of these oils. The authors use advanced optical spectroscopy techniques in correlation with dielectric measurements to understand the ageing processes in environmentally friendly oils as well as mineral oil. Firstly, different samples of environmentally friendly oils and mineral oil were utilised to investigate the ageing mechanism. The samples were subjected to different ageing periods using a thermal accelerated ageing process. Secondly, the severity of the produced byproducts due to the oil degradation is examined based on several measured properties representing macroscopic and microscopic categories. The macroscopic category was evaluated through dielectric properties, including breakdown voltage, dielectric permittivity, and dissipation factor. The microscopic category, on the other hand, was assessed using techniques such as ultraviolet–visible absorption spectroscopy and photoluminescence spectroscopy. These techniques enabled a deep understanding of the molecular‐level changes occurring in the oil under ageing conditions, thereby getting new insights into oil ageing mechanisms. It is worth mentioning that natural ester oil demonstrated the most favourable performance across various properties under ageing conditions.

Novel peptides with calcium-binding capacity from antler bone hydrolysate, its bioactivity on MC3T3-E1 cells, and the possible chelating mode.

In this study, peptide-calcium chelate was screened from antler bone hydrolysate, and its bioactivity on MC3T3-E1 cells and its chelating mechanism were investigated. Invitro experiments showed that peptide-calcium chelate promoted the differentiation and mineralization of MC3T3-E1 cells. Subsequently, three novel calcium-chelating peptides were obtained from antler bone hydrolysate using hydroxyapatite chromatography (HAC), Sephadex G-25 gel filtration chromatography, and reversed-phase high-performance liquid chromatography (RP-HPLC). Meanwhile, this work determined peptides' amino acid sequences as TKLGTQLQL, LETVILGLLKT, and KMVFLMDLLK based on LC-MS/MS. Then the present work prepared the three peptides, with the corresponding calcium-chelating rates being verified as 87.68 ± 2.86%, 80.72 ± 0.93%, and 67.96 ± 0.98%, respectively. Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible absorption (UV-vis) spectroscopy, X-ray diffraction (XRD), circular dichroism (CD), zeta potential, and molecular dynamics (MD) simulations were adopted to investigate the chelating mode of peptides with calcium ions. As a result, oxygen in the carboxyl group and the nitrogen in the amino group were related to calcium binding. In addition, the chelation site preferred the negatively charged carboxylate groups of Leu or Thr. The present work revealed that antler bone might be the new calcium-chelating peptide source and elucidated their positive role in osteogenesis.

Preparation, characterization and enhancement of intestinal iron absorption activity of β-casein phosphopeptides-iron chelate

In this study, the β-casein phosphopeptides (β-CPPs) was enzymatically prepared from β-casein, followed by the preparation of β-casein phosphopeptides-iron chelate (β-CPPs-Fe). The results of Ultraviolet–Visible absorption spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) indicated that the -COOH, O-H, N-H, and P-O-C of the β-CPPs may chelate with iron during the chelation. The amino acids involved in the chelation process were predominantly pSer, Tyr, Trp, and Phe. The scanning electron microscopy showed that due to β-CPPs combined with iron, the microsurface of β-CPPs-Fe displayed a predominantly loose porous structure. After the chelation with iron, the particle size distribution and zeta potential of β-CPPs-Fe increased. In vitro simulated gastrointestinal digestion revealed that β-CPPs-Fe demonstrated a significant increase in iron solubility compared to FeSO4·7 H2O (p < 0.05). At the endpoint of transport (180 min) in Caco-2 intestinal epithelial cell model, the amount of transferred iron for β-CPPs and β-CPPs-Fe increased by 30 % and 57 %, respectively, compared to the control group. Both β-CPPs and β-CPPs-Fe exhibited favorable effects on enhancing iron absorption, with the promotional impact of β-CPPs-Fe being notably more pronounced. The experimental findings establish a theoretical foundation for the industrial implementation of iron-fortified food products.

Facile preparation of graphene oxide/Poly (N‐Isopropylacrylamide‐co‐acrylic acid) composite thin film and its quartz crystal microbalance humidity sensing property

AbstractThe composite microgels were synthesized from N‐Isopropylacrylamide (NIPAM) and acrylic acid (AA) monomers in the presence of graphene oxide (GO) using an in situ radical copolymerization method. The successful preparation of these composite microgels was investigated through Fourier transform infrared spectroscopy (FTIR), ultraviolet visible absorption spectroscopy (UV–vis), and Raman spectroscopy. Due to the hydrophilic properties of GO and the microgels containing oxygenated groups (OH, COOH, and CONH2), quartz crystal microbalance (QCM) sensors can be fabricated by spraying the GO/P(NIPAM‐co‐AA) dispersion onto QCM sensors as sensitive coating materials. The results indicate a notable enhancement in the performance of GO/P(NIPAM‐co‐AA) modified QCM humidity sensor, compared to QCM sensors modified with either GO or P(NIPAM‐co‐AA) microgels alone. This improvement is mainly evidenced by higher sensitivity and reduced moisture hysteresis. The humidity sensing mechanism is based on the combined effect of GO and P(NIPAM‐co‐AA) microgels, which synergistically enhance the sensor's performance. Additionally, the results from water contact angle measurements, laser scanning confocal microscopy (LSCM), and scanning electron microscope (SEM) show that GO/P(NIPAM‐co‐AA) exhibits greater roughness and stronger hydrophilicity than either GO or P(NIPAM‐co‐AA) microgels alone. These properties make GO/P(NIPAM‐co‐AA) an effective moisture‐sensitive material for QCM sensors.