Bond Formation Research Articles

Improved Low-field NMR porosity characterization of cementitious materials containing water-soluble organic admixtures

Water-soluble organic admixtures (WSOAs) are widely used in cementitious materials, and may affect the porosity, but their effects on low-field nuclear magnetic resonance (LF-NMR) measurement are often overlooked. Using viscosity modifying admixture (VMA) as an example, this study demonstrates the presence of WSOAs would lead to an overestimation of porosity and a leftward shift of pore size distribution using LF-NMR. This is attributed to the formation of hydrogen bonds between polymer and water molecules, and the decreased distance between nuclear spins, respectively. A strategy is proposed to improve the accuracy of the porosity characterization by eliminating the additional effects of WSOAs in LF-NMR testing. The results show that the addition of small molecular mass non-ionic VMAs replacing mixing water (within a 20 % replacing rate) does not alter the porosity of the paste. This method can be extended to characterize the porosity of various porous materials containing WSOAs.

Functionality, physicochemical properties, and applications of chitosan/nano-hydroxyapatite–tea polyphenol films

An active chitosan (CS) film containing a nano-hydroxyapatite–tea polyphenol (HAP-TP) complex was designed and prepared. The effects of HAP-TP loading on the structural and physicochemical properties of the CS-based film were evaluated. The mechanical and thermal properties of the film were significantly improved by the resulting intermolecular interactions and formation of hydrogen bonds between HAP-TP and CS, which reduced the water vapor and oxygen permeabilities of the film by 29.78 and 35.59 %, respectively. The CS-HAP-TP film exhibited excellent slow-release behavior and antioxidant activity, with a cumulative release rate at 700 h 6.79 % lower than that of CS-TP films. The CS-HAP-TP film significantly inhibited the deterioration of semi-dried golden pompano, and thus helped to retain the taste of umami and sweet amino acids in fish samples, while reducing off-flavor generation. The film therefore shows considerable potential as an active packaging material for the preservation of semi-dried fish products.

Surface Phase Stability of High-Nickel Layered Oxides by Titanium and Sulfur Co-modifications

High-nickel layered oxides are promising cathodes for lithium-ion batteries due to relatively high capacity and low cost, which however are still faced with safety issues because of poor stability against cycling. Herein, a facile one-pot solid-state method is employed for preparation of trace Ti/S co-doped LiNi0.98Co0.02O2. Ti and S co-doping enhances both rate capability and intrinsic stability greatly in a mutually promoting manner compared to individual Ti and S doping. The co-doped samples show excellent rate capability with 170.9 mAh g-1 at 5 C and superior intrinsic stability with a capacity retention of 88.6% at 1 C after 200 cycles at room temperature (50 oC), in sharp contrast with 132.2 mAh g-1 and 61.6% for the pristine samples. Full cells achieve excellent long-term stability with a retention of 92.7% after 400 cycles at 1 C. The improved performance can be ascribed to the formation of stronger Ti-O bonds and of a thin rock-salt protective layer enabled by sulfur with the stability enhanced by Ti modifications, and the activation of extra redox reactions triggered by sulfur. The mutually promoting enhancement effect by doping different alien elements opens a new and unique design strategy for performance improvement of electrode materials.

Identification of a novel RHCE*Ce (829G > A) allele associated with absence of C and e antigens expression.

The Rh blood group antigens are encoded by the RHD and RHCE genes, which possess a remarkable degree of polymorphism owing to their high homologous structures. These variants of the RH genes can lead to absence or weak expression of antigens. Analysis of RHCE genotyping by Polymerase Chain Reaction (PCR-SSP) method specific to detect c.48G, c.48C, 109 bp insertion of IVS2, c.201A and c.307C and RhCE phenotyping, were conducted in 316 Chinese patients in previous study. One patient with discrepancy typing result was collected for further RhCE serologic typing using microcolumn gel method and tube method in saline using monoclonal antibodies. PacBio sequencing was performed for RHCE, RHD and RHAG complete sequence analysis. 3D molecular models of the protein with the wild-type and mutant residue were generated using the DynaMut web server. The effect of the mutation on the protein function was predicted by PolyPhen-2 software. One male patient of Chinese Han was detected with RHCE*C allele showed by PCR-SSP method but ccEE phenotype. Further PacBio sequencing identified one normal RHCE*cE allele and one RHCE*Ce allele carried a novel c.829G > A (p.Gly277Arg) variant, which the encoded amino acid located in the ninth transmembrane segment of RhCE protein. Crystallisation analysis of 3D molecular models revealed that the substitution at Arg277 leads to the formation of additional hydrogen bonds, including weak hydrogen bonds between multiple atoms. It also results in hydrophobic ion interactions between Arg277 and Ala244. This mutation is predicted to have a damaging effect on protein function. One novel RHCE*Ce allele with c.829G > A (p.Gly277Arg) variant was identified to resulting in the absence or weak expression of C and e antigens.

The evaluation of the interaction of baicalein (5,6,7-trihydroxyflavone) with human IgG and a glioblastoma multiforme (GBM) cell line

Baicalein, a nutritional phenolic bioactive small molecule present in the roots of Scutellaria baicalensis and Scutellaria lateriflora, shows promising therapeutic effects against a wide range of cancer cells. However, its potential binding with blood carrier proteins and its anticancer mechanisms have not been well investigated. In this study, the interaction between baicalein and immunoglobulin G (IgG) was analyzed by analyzing intrinsic fluorescence, ellipticity changes, as well as molecular docking. The anticancer effects of baicalein against a glioblastoma multiforme (GBM) cell line, U87MG, and one normal immortalized human astrocytes were assessed by MTT, real-time PCR, caspase assay, and western blot. It was shown that fluorescence quenching mechanism of human IgG by baicalein was based on a static quenching, where one binding site was responsible for the formation of baicalein-IgG complex derived by the formation of hydrogen bonds and van der Waals forces. Molecular docking study indicated that tyrosine residues (Tyr 91 and Tyr 98) were mostly involved in the binding site of baicalein to IgG. The cellular assay demonstrated that baicalein induced U87MG cell line death with an IC50 concentration of 73.19 µM, whereas normal astrocytes depicted over 82.94 % portion of viability at 100 µM baicalein. The Bax mRNA overexpression, Bcl-2 mRNA downexpression, as well as the elevation of caspase-9 and caspase-3 activities confirmed that baicalein could effectively trigger the apoptosis of U87MG cells. Moreover, it was explored that baicalein downregulated the expression of the Axl/STAT3 signaling pathway in the U87MG cells, which is responsible for cellular proliferation and growth. In conclusion, these data may provide useful information regarding the pharmaceutical application of baicalein.

Collaborative intercalation and reduction of graphene oxide for highly stable and efficient nanofiltration membranes

Two-dimensional (2D) materials, known for their atomically thin profiles and micrometer transverse dimensions, have garnered considerable attentions in membrane technology. Despite their potential, 2D membranes comprising stacked nanosheets often suffer from low permeability and poor stability. Addressing these challenges, we applied collaborative intercalation and reduction strategies to enhance permeability and stability of graphene oxide (GO)-based membranes. We intercalated 2-hydroxypropyl-β-cyclodextrin (2β-CD) into the GO nanosheet dispersion under heat treatment and employed vacuum assisted self-assembly to fabricate the 2β-CD intercalated reduced GO (CD-rGO) membrane. During this process, GO nanosheets underwent reduction, facilitating the formation of hydrogen bonds between 2β-CD and GO. The resulting CD-rGO membrane exhibited markedly improved water permeance at 96.9 L m−2 h−1 bar−1 and an impressive rejection rate at 99.5 % towards Congo red, alongside enhanced stability under a 20 min ultrasonic test at 180 W, and pressure and long-term stability under the cross-flow filtrate tests. The introduction of 2β-CD during heat treatment not only increased the interlayer distance but also utilized the intrinsic pores of 2β-CD and enhanced surface hydrophilicity, contributing to superior separation performance These collaborative strategies offer a facile and promising approach towards high-performance 2D laminated GO-based membranes.

Microbubble-enhanced cold plasma activation (MB-CPA) for surface functionalization of polymer nanoparticles from nanoprecipitation

Cold plasma activation has been considered as a green and effective technological approach for functionalization of solid surfaces. In the current study, we introduce a versatile technique known as microbubble-enhanced cold plasma activation (MB-CPA) for surface modification of polymer plates and nanoparticles in flowing liquid phase. Corona plasma is generated at the inlet of a venturi tube, thereby creating a highly excited state in the air. Reactive nitrogen and oxygen species (RNOS) are transferred from the gas phase to the suspension flow in the form of plasma microbubbles. Two types of polymer-based nanoparticles in the suspension, namely polymethyl methacrylate (PMMA) of 16–154 nm and polycaprolactone (PCL) of 30–225 nm, are synthesized using nano-precipitation method. Through the degradation of model compounds, the polar organic solvent, acetone and ethanol, is found to promote or suppress the production of active species. In addition, the efficiency of the MB-CPA treatment depends on the solvent composition, making this technology a controllable and efficient strategy for the surface modification of nanoparticles. The findings indicate that plasma activation effectively reduces the negative surface zeta-potentials and induces aggregation and separation in the suspensions. The infrared spectra of the treated nanoparticles reveal that plasma activation leads to the formation of NH and CN bonds situated on the surface of PMMA. Our work demonstrates that organic-solvent involved MB-CPA emerges as a promising method for the surface modification of nanoparticles in the flow condition.

Exploring a facile preparation method for Co-Ni/MoS2-derived nanohybrid from wheat straw extract and its physicochemical properties.

This study presents a novel approach for the fabrication of a Co,Ni/MoS2-derived nanohybrid material using wheat straw extract. The facile synthesis method involves a sol-gel process, followed by calcination, showcasing the potential of agricultural waste as a sustainable reducing and chelating reagent. The as-prepared nanohybrid has been characterized using different techniques to analyse its physicochemical properties. X-ray diffraction analysis confirmed the successful synthesis of the nanohybrid material, identifying the presence of NiMoO4, CoSO4 and Mo17O47 as its components. Fourier-transform infrared spectroscopy differentiated the functional groups present in the wheat straw biomass and those in the nanohybrid material, highlighting the formation of metal-oxide and sulphide bonds. Scanning electron microscopy revealed a heterogeneous morphology with agglomerated structures and a grain size of around 70 nm in the nanohybrid. Energy-dispersive X-ray spectroscopy analysis shows the composition of elements with weight percentages of (Mo) 9.17%, (S) 6.21%, (Co) 12.48%, (Ni) 12.18% and (O) 50.46% contributing to its composition. Electrochemical analysis performed through cyclic voltammetry showcased the exceptional performance of the nanohybrid material as compared with MoS2, suggesting its possible applications for designing biosensors and related technologies. Thus, the research study presented herein underscores the efficient utilization of natural resources for the development of functional nanomaterials with promising applications in various fields. This study paves a way for manufacturing innovation along with advancement of novel synthesis method for sustainable nanomaterial for future technological developments.

Efficient extraction of gold from aqueous solution by azo-phenylthiourea functionalized Zr-MOF

The design and synthesis of effective adsorbent for extracting gold from wastewater has significant environmental and economic implications. However, the development of an adsorbent with high efficiency remains challenging. Herein, we report the synthesis of an azo-phenylthiourea functionalized metal-organic framework (MOF, azo-PT-UiO-66) and its application for the adsorption of Au(Ⅲ) from aqueous solution. The performance of azo-PT-UiO-66 was significantly improved as compared with the unmodified MOF, achieving an adsorption capacity up to 650.07 mg/g. Based on the results of kinetic, isothermal and thermodynamic studies, the adsorptive behaviour was a homogeneous and spontaneous chemisorption. Moreover, characterizations revealed that the appearance of metallic gold was caused by the reduction of Au(Ⅲ) via -NH2 groups. The density functional theory (DFT) calculations confirmed that the chemisorption is owing to the formation of coordinate bonds between azo, S and Au(Ⅲ). This work provides a clean and sustainable method for the recovery of gold from industrial wastewater.

Sustainable composites with synergistic combinations of construction and demolition waste: Behavior of rubber, HDPE, PS, and brick after short-term water immersion

The growing concern for environmental sustainability and construction and demolition (C&D) waste management has led to innovative approaches to recycling and reusing these materials. This study presents the development of sustainable composites using a unique mix of C&D wastes: rubber, high-density polyethylene (HDPE), polystyrene (PS), and bricks. Mechanical tests were performed to determine their structural integrity and suitability for construction applications. The composites were further subjected to immersion in water to evaluate their resistance to environmental factors. In addition, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses were performed to obtain information on the chemical and morphological properties of the composites. The synergy achieved by combining C&D waste materials such as rubber, HDPE, PS and bricks resulted in composites that exhibited outstanding mechanical properties. The samples with the composition rubber:HDPE:PS:brick = 15:40:40:5 immersed in water for 21 days presented the best mechanical resistance properties: Rc = 146.51 MPa, Ei = 36.05 kJ/m2, Rt = 11.2 MPa. The results demonstrated that the composites maintained their structural integrity and did not undergo significant degradation when exposed to moisture, highlighting their potential for use in wet or humid environments. FTIR analysis provided valuable information on the chemical composition of the composites. The interactions between the individual components led to the formation of new chemical bonds, strengthening the overall structure of the composite material. SEM images revealed a homogeneous distribution of the components in the composites, confirming their excellent compatibility. XRD analysis showed that the crystal structure of the composites was optimized for mechanical performance, further supporting their suitability for construction applications.

First-principles studies of gas molecule adsorption on a LaB6(100) surface.

First-principles calculations were employed to study the molecular and dissociative adsorption of CO2, H2O, O2 and N2 on a LaB6(100) surface. The adsorption energy calculation results indicate that these gas molecules can form thermodynamically stable adsorption structures. Dissociative adsorption is always accompanied by more electron transfer compared to molecular adsorption, which is one of the necessary conditions for dissociation to occur. Bader charge analysis indicates that the adsorption of gas molecules on the LaB6(100) surface is always accompanied by electron transfer from the surface to the adsorbed molecules. This electron transfer forms a dipole moment from the adsorbed molecule towards the surface, leading to an increase in the work function of LaB6(100). This mechanism is a crucial aspect of the LaB6(100) poisoning effect. Additionally, LaB6(100) sometimes exhibits a certain degree of resistance to poisoning. In such cases, after the adsorption of gas molecules, local regions of the LaB6(100) surface become negatively charged, which counteracts the poisoning effect to some extent. Using electronic density of states and electron localization function analyses, we examined the nature of the chemical bonds. It was found that La tends to form non-covalent bonds with the adsorbates, whereas B tends to form covalent bonds with them. The 2p orbitals of B play a significant role in the formation of these covalent bonds in most cases.

Iodoxybenzoic Acid (IBX) in Organic Synthesis: A Septennial Review.

This study reviews the oxidative applications of 2-iodoxybenzoic acid (IBX) in organic synthesis, focusing on C-H functionalization, hetero-hetero bond formations, ring cleavage reactions, dehydrogenation, heterocyclic ring formations, and some miscellaneous reactions in a comprehensive and critical way. It compiles the literature starting from mid-2015 to date.

Theoretical insight into the NO* Coverage-Dependent selectivity of Pd and Cu electrocatalysts for nitrate reduction

Nitrate (NO3−) is a concerning contaminant in groundwater that is harmful to human health. Electrocatalytic reduction of NO3− can be achieved with transition metals such as Pd and Cu. In this work, we apply density functional theory (DFT) to discern how the electronic properties of the metal catalyst affect the selectivity of the nitrate reduction mechanism toward either N2 products (e.g., N2 and N2O) or N1 products (e.g., NH3 and NH4+). We find that the greater d-band filling of Cu results in more electron accumulation on the N atom of adsorbed NO*, which drives N–H bond formation favoring the production of HNO* and eventually N1 products (NH3). Conversely, the more delocalized d orbitals of Pd lead to a strong adsorbate–adsorbate coverage effect that lowers key N–N coupling barriers at high NO* coverage favoring selectivity toward N2 products (N2 and N2O). This work elucidates why, at the electronic-structure level, nitrate reduction is highly sensitive to NO* coverage on some metals (such as Pd) and less so on others (such as Cu).

Improving the gel properties of Ficus pumila Linn. pectin by incorporating deacetylated konjac glucomannan.

To improve the gelation behaviour of pectin, the effect of deacetylated konjac glucomannan (DKGM) with various deacetylation degrees (27.44%, 44.32%, 60.25%, and 71.77%) on the heat-induced gel characteristics of Ficus pumila Linn. pectin was studied. The hardness, chewiness, and adhesiveness of the gel increased as the degree of deacetylation increased from 27.44% to 60.25%, but decreased at 71.77%. Additionally, DKGM addition resulted in higher apparent viscosity and non-Newtonian fluid behaviour in the composite gel. The incorporation of DKGM into the gel matrix strengthened the gel structure by promoting hydrogen bond formation and shortening relaxation time compared to the control. Scanning electron microscopy images revealed that the densification of the pectin gel network increased as the degree of deacetylation of konjac glucomannan rose from 27.44% to 60.25%, but then loosened when it exceeded 71.77%. As the degree of deacetylation increased, the hydrophobic interaction between pectin and DKGM increased. Overall, the addition of DKGM effectively modulated the gel properties of Ficus pumila Linn. pectin, thus broadening its industrial application on different gel products.

Curcumin loaded starch-based aerogels interfere with quorum sensing regulated virulence functions and biofilm of bacterial pathogens

Over the last two decades, the sharp escalation of antimicrobial resistance (AMR) has emerged as a formidable threat to human health. This pressing situation demands innovative interventions to combat infectious diseases. Aerogels, characterized by their nanostructured composition and high porosity, present a promising avenue. In this study, we manufactured curcumin loaded starch-based aerogels (CSA) and evaluated their impact on the quorum sensing (QS) mechanism in Gram-negative bacteria. Fourier-transform infrared (FTIR) analysis highlighted the presence of cellulose hydroxyl groups engaged in hydrogen bond formation. Thermogravimetric analysis (TGA) revealed that over 50 % of the initial mass was lost when CSA underwent heating to 350 °C. Microscopic examination showcased a uniform and compact pattern, suggesting reduced pore distribution. The elemental composition analysis indicated that carbon and oxygen constituted 23.00 % and 77.00 % of the weight, respectively. The presence of CSA resulted in over 30.4 % inhibition of violacein pigment production. Furthermore, CSA modulated pyocyanin production, pyoverdin production, LasB elastase activity, and rhamnolipid production by 34.4 %, 31.07 %, 22.7 %, and 19.7 %, respectively. The total exoproteases, cell surface hydrophobicity and exopolysaccharide production in E. coli, L. monocytogenes, S. marcescens, and P. aeruginosa, experienced a significant decrease at sub-MICs. Production of biofilms as well as the mature biofilms in test bacteria were reduced in dose-dependent manner significantly. Due to their antibiofilm and anti-quorum sensing properties, these CSAs could prove to be functional biomaterials with versatile applications, particularly in the food industry.

Fusion of immiscible covalent adaptable networks rooted in Enamine-One and β-Amino ester bonds with robust mechanically and excellent re-processing properties

Covalent adaptable networks (CANs) are widely used because of their outstanding mechanical properties and reprocessibility. However, these materials can only be recycled with mono-dynamic bonding networks during recovery. Here, we report that fused polymer CANs containing bi-dynamic bonds with adjustable mechanical properties are achieved through the dynamic behavior of the β-amino ester bond and the enamine-one bond. The β-amino ester bond-based CANs (P1) and the enamine-one bond-based CANs (P5) were prepared using tris(2-aminoethyl)amine (TREN) and m-xylylenediamine (MXDA) with hexanediol diacrylate and hexane-1, 6-diyl dipropiolate via click reaction, respectively. The mechanical and thermal properties of the fused films obtained after grinding and mixing at room temperature were comparable to those of CANs containing bi-dynamic bonds obtained by pre-mixing TREN and MXDA. Dynamic exchange and topological bond formation by the β-amino ester and the enamine-one at the interface are shown at the molecular level and with high uniformity. CANs containing bi-dynamic bonds showed synergism in stress relaxation experiments, demonstrating variable activation energies over a range of the temperature window. Owing to their excellent puncture resistance, the prepared materials can be used in flexible devices, energy-storage equipment, and various other applications.

Interaction between peptide and solid lignin suggest mechanisms of abiotic covalent bond formation

The mechanisms behind the formation of soil organic matter (SOM) and associated nitrogen immobilization remain partially elusive, while ongoing research continues to shed light on carbon and nitrogen sequestration in the environment. Studies show that quinone-like structures within alkali-soluble humic extracts of SOM can bond covalently with nitrogen-containing molecules derived from proteinaceous organic matter. However, direct molecular evidence for this chemical bonding with lignin in the solid form and non-solvent-extracted SOM is lacking. Using gel-state 1H-15N heteronuclear single quantum coherence (HSQC) high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy, we demonstrate that a 15N-labeled peptide (glycine-glycine-glycine-arginine, GGGR), can covalently bind to solid, untreated, brown rotted wood as well as 1,2-naphthoquinone, a quinone-model molecule typically found in degraded lignin. The new peaks in both reactions represent a change in the environment surrounding the N-functional groups. Interaction of the 15N-labeled peptide with the model quinone produced NMR cross peaks that are similar to those of the solid lignin. This suggests that the quinone-like structures are the most likely functional groups to form covalent bonds with peptides in the degraded lignin. Both Michael addition and Schiff base formation is proposed when the peptide GGGR interacts with white oak lignin and 1,2-naphthoquinone. These processes are of considerable importance to N incorporation into SOM and offer insights into how proteinaceous molecules could potentially be preserved and sequestered through covalent bond formation.

Epididymal mRNA expression profiles for the protein disulfide isomerase gene family: Modulation by development and androgens.

The endoplasmic reticulum (ER) is the central hub for protein quality control, where the protein disulfide isomerases (PDIs), encoded by at least 21 genes, play a pivotal role. These multifunctional proteins contribute to disulfide bond formation, proper folding, and protein modifications, and may act as hormone-binding proteins (e.g., steroids), influencing hormone biology. The interplay between ER proteostasis, PDIs, and epididymis-a crucial site for sperm maturation-remains largely understudied. This study characterizes transcriptional signatures of Pdi genes in the epididymis. Transcriptional profiles of selected Pdi genes were assessed in adult Wistar rat tissues, and epididymis under different experimental conditions (developmental stages, surgical castration, and efferent ductules ligation [EDL]). In silico bioinformatic analyses identified expression trends of this gene family in human epididymal segments. P4hb, Pdia3, Pdia5, Pdia6, Erp44, Erp29, and Casq1 transcripts were detected in both reproductive and non-reproductive tissues, while Casq2 exhibited higher abundance in vas deferens, prostate, and heart. Pdilt, highly expressed in testis, and Pdia2, highly expressed in heart, showed minimal mRNA levels in the epididymis. In the mesonephric duct, epididymal embryonic precursor, P4hb, Pdia3, Pdia5, Pdia6, and Erp29 mRNAs were found at gestational day (GD) 17.5. Except for Erp29, which remained stable, these Pdi transcript levels increased from GD17.5 to GD20.5, when epididymal morphogenesis occurs, and were maintained to varying degrees in the epididymis during postnatal development. Surgical castration downregulated P4hb, Pdia3, Pdia5, Pdia6, Pdilt and Erp29 transcripts, an effect reversed by testosterone replacement. Conversely, transcript levels remained unaffected by EDL, except P4hb, which was reduced in caput epididymis. All 21 PDI genes exhibited diverse transcriptional profiles across the human epididymis. The findings lay the foundations to explore Pdi genes in epididymal biology. As a considerable proportion of male infertility cases are idiopathic, targeting hormonal regulation of protein quality control in epididymis represents a route to address male infertility and advance therapeutic interventions in this domain.

Exploring the Enhanced Oxidation Potential through Green Synthesis of Ofloxacin–Silver Complex: Investigating Silver and Ofloxacin Interaction at Varied Concentrations

The purpose for this work is to synthesize ofloxacin–Silver(I) complex with the highest oxidation potential in liquid state with green methodology. Initially, we investigated the complexation of the OFL ligand with silver ions using UV-visible spectrophotometry, differential pulse wave voltammetry, and electrochemical impedance spectroscopy. The UV-visible results indicated the interaction between OFL and Ag+ through a complexation reaction. Notably, the peak corresponding to OFL oxidation at 0.98 V showed a significant increase in the presence of silver, leading to an oxidation potential shift towards positive values attributed to the bond formation between the OFL and Ag+. In terms of structural characterization, various spectroscopic analyses were employed, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and scanning electron microscopy. The OFL–Ag+ complex formation was confirmed by the appearance of two distinct sharp bands at 547 and 950 cm−1 in the FTIR spectra. The average particle diameter of the OFL–Ag+ complex was determined to be 187.5 nm. This complex, synthesized as a brown solid powder soluble in water, exhibited the highest oxidation potential of 1.32 V. Hence, it holds promise for potential application in antibacterial activity.

Design of silver nanoparticle-embedded nano zirconium-based metal-organic frameworks for highly sensitive detection of chlorpyrifos in real samples.

Chlorpyrifos (CPS) is widely found in food and water sources due to agricultural use, posing health and environmental risks. Therefore, this work introduces a fluorescent sensor design of silver nanoparticle-embedded nano zirconium-based metal-organic frameworks (UiO-66-NH2@AgNPs) for accurate examination of CPS. Briefly, UiO-66-NH2 was synthesized hydrothermally, exhibiting weak luminescence owed to ligand-to-metal charge transfer (LMCT). Here, it limits its direct utility in fluorescence-based detection. To address this limitation, silver nanoparticles (AgNPs) were introduced into UiO-66-NH2, enhancing fluorescence via the metal-enhanced fluorescence (MEF) effect. Briefly, a comprehensive spectral analysis such as XPS, SEM, TEM, PXRD, etc., was performed to validate the synthesis of UiO-66-NH2@AgNPs. Subsequent evaluation revealed that CPS effectively quenched the luminescence intensity of UiO-66-NH2@AgNPs through a static quenching mechanism. The fluorescence intensity exhibited good linearity with CPS concentration in the span of 10 to 1,000 ng/mL, with a recognition limit of 191.5ng/mL(S/N = 3). The interaction involved Ag-S bond formation and electrostatic interactions, reducing fluorescence intensity. The method was confirmed through successful CPS detection in fruit samples. The UiO-66-NH2@AgNPs nanoprobe offers a simple, sensitive, and accurate platform for CPS sensing, with potential for future use in detecting CPS in fruits and vegetables.