Dual Metal Ions Research Articles

A synergistic enhancement strategy for mechanical and conductive properties of hydrogels with dual ionically cross-linked κ-carrageenan/poly(sodium acrylate-co-acrylamide) network

Applying conductive hydrogels in electronic skin, health monitoring, and wearable devices has aroused great research interest. Yet, it remains a significant challenge to prepare conductive hydrogels simultaneously with superior mechanical, self-recovery, and conductivity performance. Herein, a dual ionically cross-linked double network (DN) hydrogel is fabricated based on K+ and Fe3+ ion cross-linked κ-carrageenan (κ-CG) and Fe3+ ion cross-linked poly(sodium acrylate-co-acrylamide) P(AANa-co-AM). Benefiting from the abundance of hydrogen bonds and metal coordination bonds, the conductive hydrogel has excellent mechanical properties (fracture strain up to 1420 %, fracture stress up to 2.30 MPa, and toughness up to 20.63 MJ/m3) and good self-recovery performance (the recovery rate of the toughness can reach 85 % after waiting for 1 h). Meanwhile, due to the introduction of dual metal ions of K+ and Fe3+, the ionic conductivity of conductive hydrogel is up to 1.42 S/m. Furthermore, the hydrogel strain sensor has good sensitivity with a gauge factor (GF) of 2.41 (0–100 %). It can be a wearable sensor that monitors different human motions, such as sit-ups. This work offers a new synergistic strategy for designing a hydrogel strain sensor with high mechanical, self-recovery, and conductive properties.

Dual structure cobalt sites on surface hydroxyl and oxygen vacancy of BiOCl for cooperative CO2 reduction and tetracycline oxidation

Metal ion cocatalysts have huge prospect for photocatalytic CO2 reduction coupled with organic decomposition because of their cost effectiveness and abundant active sites. Herein, we exploit a defect−group oriented tactic to induce dual−structured Co sites on BiOCl with rich surface hydroxyls (OHs) and oxygen vacancies (OVs) (labeled as BiO1−xCl−OH), in which the surface OHs and OVs acted as anchoring points to anchor Co2+ ions. Density functional theory calculations manifested that surface OHs anchored Co2+ ions via hydrogen bonding to produce tight OH−Co sites, meanwhile, surface OVs with unsaturated metal sites and unpaired electrons captured Co2+ ions through chemical bonding to form close−knit OV−Co site. The as−generated OV−Co and OH−Co site served as reductive and oxidative cocatalyst for CO2 reduction and tetracycline oxidation, respectively, thereby achieving high−efficiency redox activity. This work provided a novel strategy to devise progressive dual functional metal ions cocatalysts for high−efficiency CO2 reduction and organic pollutants oxidation.

Upconversion nanoparticles-CuMnO2 nanoassemblies for NIR-excited imaging of reactive oxygen species in vivo

Here, we designed a ratiometric luminescent nanoprobe based on lanthanide-doped upconversion nanoparticles-CuMnO2 nanoassemblies for rapid and sensitive detection of reactive oxygen species (ROS) levels in living cells and mouse. CuMnO2 nanosheets exhibit a wide absorption range of 300–700 nm, overlapping with the visible-light emission of upconversion nanoparticles (UCNPs), resulting in a significant upconversion luminescence quenching. In an acidic environment, H2O2 can promote the redox reaction of CuMnO2, leading to its dissociation from the surface of UCNPs and the restoration of upconversion luminescence. The variation in luminescence intensity ratio (UCL475/UCL450) were monitored to detect ROS levels. The H2O2 nanoprobe exhibited a linear response in the range of 0.314–10 μM with a detection limit of 11.3 nM. The biological tests proved the excellent biocompatibility and low toxicity of obtained UCNPs-CuMnO2 nanoassemblies. This ratiometric luminescent nanoprobe was successfully applied for the detection of exogenous and endogenous ROS in live cells as well as in vivo ROS quantitation. The dual transition metal ions endow this probe efficient catalytic decomposition capabilities, and this sensing strategy broadens the application of UCNPs-based nanomaterials in the field of biological analysis and diagnosis.

Harnessing bimetallic iMWA nanosensitizer to unleash ferroptosis and calcium overload: Unlocking tumor vulnerability for potentiated iMWA therapy against hepatocellular carcinoma

Microwave ablation (MWA) holds promise as a tumor treatment modality, yet incomplete ablation with low-frequency MWA (iMWA) remains a significant obstacle to survival, while the high-frequency MWA poses safety concerns. To address these challenges, we introduce a novel bimetallic iMWA nanosensitizer, CFT-NPs, constructed via metal-coordination interactions between tannic acid (TA) and iron/calcium dual metal ions (Fe3+/Ca2+). The Fe3+/Ca2+ in CFT-NPs work in harmony to convert electromagnetic energy into heat, thereby bolstering the effectiveness of iMWA while maintaining good biosafety. Furthermore, the pH-triggered rupture of CFT-NPs release TA, Fe3+, and Ca2+. The liberated Fe3+ undergoes reduction by TA, and when combined with Ca2+, they trigger ferroptosis and Ca2+ overload respectively, significantly amplifying the therapeutic effects of iMWA. Utilization iMWA with CFT-NPs results in lipid oxidation, mitochondrial dysfunction, and disruption of redox balance, both in vitro and in vivo. Notably, this nanosensitizer exerts a robust antitumor effect, effectively inhibiting tumor growth and downregulating the expression of matrix metalloproteinases, which is associated with tumor metastasis. Collectively, this innovative study offers a promising approach to overcome the challenges of incomplete ablation and biological safety, enhancing the antitumor efficacy of iMWA..

Sustainable fabrication of fluorescent carbon quantum dots as an optical amplifier in modern agriculture, anti-counterfeiting, food packing and intelligent pH detection

Carbon quantum dots (CQDs) have received a great deal of attention due to their distinctive luminescent features and exciting potential applications in the fields of agronomy, enhanced anti-counterfeiting, drug tracking and intelligent sensing and detection. The focus of the current effort is on easily transforming toxic, non-biodegradable waste expanded polystyrene foam (WEPS) into extremely luminescent CQDs and investigating their various applications. As a nano-priming agent for Cajanus cajan (L.), the green pigeon pea (GPP), WEPS derived CQDs are used. The outcomes showed that seed priming had beneficial effects at all CQDs concentrations (100–900 mg/L), including accelerated seed germination rate, increased shoot and root length, augmented root vigour, higher chlorophyll content and biomass accumulation in comparison to the control groups. The most crucial data coding can be protected under 365 nm UV light using the optimized CQDs concentration (700 mg/L) blue fluorescent ink. In addition, a straightforward sensing platform with high sensitivity and selectivity is needed for the detection of dual metal ions, as well as one with a "turn-on and turn-off" fluorescence (FL) response. Additionally, a composite film containing well-dispersed CQDs (700 mg/L) in polyvinyl alcohol and strong hydrogen-bond interaction is successfully developed to alleviate the FL quenching caused by CQD aggregation. The resulting film had extraordinary FL performance, good mechanical flexibility and high transparency (transmittance of 90 %). Even more remarkably, this luminescent film showed sensitive pH responsiveness, signifying that when pH is stimulated, the FL intensity changed. A smart pH-detector based on this luminescent film is logically created as a proof-of-concept for real-time sensing and detection of pH changes in human sweat. These results show that WEPS derived CQDs have enormous potential as nano-priming agents for seed germination, seedling development, anti-counterfeiting ink, food packaging and intelligent pH-detector in wearable, real-time health monitoring.

Competition between dual alkali metal ions fuels high-performance sodium-ion batteries

Dual alkali metal ion battery is expected to apply in future high-efficiency energy storage applications as it can skillfully combine the advantages of Li+ and Na+. However, the specific insertion and extraction processes of the two ions are not well explained. Herein, a layered sodium transition metal oxide electrode with ordered mixing of Na/Li ions is prepared by ion exchange method. The ion behavior is explained in terms of activation energy of chemical reaction and Gibbs free energy. Based on thermodynamic analysis and material characterizations, the priorities of Na+ and Li+ deblock reactions are determined. The competition mechanism of alkali metal ions and the double gain effect of Li are revealed by electrochemical experiments. This work is expected to provide a positive impact on the future design of multifunctional cathodes for advanced rechargeable batteries.

Tailoring the solvation shells of dual metal ions for high-performance aqueous zinc ion batteries

For a long time, the issue of dendrites in neutral/mild electrolyte-based aqueous zinc-ion batteries (AZIBs) has been a matter of concern. The dendrites resulting from this problem lead to short-circuit faults and significantly reduce the cycle life, which is quite troublesome. Here, we induce uniform Zn deposition by utilizing the enhanced electrostatic shielding effect of a hybrid additive of Na2SO4 and EDTA. The limited tip-blocking effect of Na+ is due to the higher exchange reaction rate constant (kex) of water molecules in the solvation shell. The coordination of EDTA can provide a more stable solvation shell for Na+, ensuring a stronger blocking effect on Zn deposition at the tip. This enhanced electrostatic shielding effect effectively suppresses the growth of Zn dendrites. In addition, EDTA also enters the solvation shell of Zn2+ and displaces some coordinated water molecules, allowing for more reversible Zn plating/stripping without significant side reactions occurring at the Zn anode.

Visible light-driven Z-scheme Bi2O3/CuBi2O4 heterojunction with dual metal ions cycle for PMS activation and Lev degradation

In this study, Bi2O3/CuBi2O4 composite was prepared by sol–gel method, which was used to degrade levofloxacin (Lev) by the synergistic effect of visible light and peroxymonosulfate (PMS). The physicochemical properties of Bi2O3/CuBi2O4 were regulated by varying the molar ratio of the raw materials. The structure and morphology of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). Secondly, Bi2O3/CuBi2O4/Vis/PMS system was constructed to investigate the effects of different conditions (pollutant concentration, catalyst dosage, PMS concentration, pH and different anion concentration) on the removal effect of Lev. Benefit from the highly ordered alternating nanoparticles and nanosheets, Bi2O3/CuBi2O4 showed satisfactory PMS activation ability than single Bi2O3. The degradation rate increased from 12.98 ± 2.41% (Bi2O3) to 70.62 ± 0.07% (Bi2O3/CuBi2O4) within 120 min. Finally, the quenching experiments and electron paramagnetic resonance (EPR) results showed that radical pathways (h+, SO4-·, ·OH) and non-radical pathways (1O2) were both involved in the PMS activation process. The main reaction mechanism of Bi2O3/CuBi2O4/Vis/PMS system was predicted, the unique electron transfer pathway of Z-scheme heterojunction and Cu(II)/Cu(I), Bi(V)/Bi(III) redox-cycle on the catalyst surface effectively drove the generation of radicals, realizing the high efficiency of pollutant degradation.

Spectral studies of synthetic symmetric syringaldehyde di-Schiff azine with β-cyclodextrin inclusion complexes as a fluorescent probe for the detection of metal ions

In the past few years, organic fluorescent probes play a crucial role in sensor fields due to their magnificent selectivity and detection ability towards various transition metals and alkali ions. Herein, A facile and profitable Schiff-based symmetrical azine derivative of 4,4′ ((1E,1′E)-hydrazine-1,2-diylidenebis(methanylylidene)) bis2,6-methoxyphenyl, dihydrazone or syringaldehyde Azine (SyA) has been synthesized which was rapidly detected dual metal ions (Cu2+ and Pb2+) in different mechanism pathway via Chelation Enhanced Fluorescence Mechanism (CHEF) and Ligand to Metal Charge Transfer (LMCT) approach in optimized physiological conditions under ACN medium. Simultaneously, the interaction mechanism between the SyA and both metals was studied with the help of Benesi-Hildebrand and 1H NMR spectroscopy. Afterward, we prepared the inclusion complex of β-cyclodextrin with SyA (β-CD:SyA) to enhance water solubility and sensing probability. The complex for the observed surprising result was that complexation not only enhanced their properties and detected the new metal ion of Al3+ (may be due to β-CD hydroxyl group interaction with metal ions) without disturbance detection of Cu2+ and Pb2+. The LOD and binding constant values of SyA and β-CD:SyA towards Cu2+, and Al2+ were calculated by absorbance and fluorescence titration profile. From an application point of view, the antibacterial activity and biological activities were evaluated.

Preparation of sodium alginate gel microspheres catalysts and its high catalytic performance for treatment of ciprofloxacin wastewater

The discharge of the antibiotic wastewater has increased dramatically in our country with the development of medical science and wide application of antibiotic, resulting in serious harm to human body and ecological environment. In this work, ciprofloxacin (CIP) was selected as one of typical antibiotics and heterogeneous Fenton-like catalysts were prepared for the treatment of ciprofloxacin wastewater. The sodium alginate (SA) gel microspheres catalysts were prepared by polymerization method using double metal ions of Fe3+ and Mn2+ as cross-linking agents. Preparation conditions such as metal ions concentration, mass fraction of SA, polymerization temperature and dual-metal ions as crosslinking agent were optimized. Moreover, the effects of operating conditions such as initial concentration of CIP, pH value and catalyst dosage on CIP removal were studied. The kinetic equation showed that the effect of the initial concentration of CIP on the degradation rate was in line with second-order kinetics, and the effects of catalyst dosage and pH value on the degradation rate of CIP were in line with first-order kinetics. The SA gel microspheres catalysts prepared by dual-metal ions exhibited a high CIP removal and showed a good reusability after six recycles. The SA gel microspheres catalysts with an easy recovery performance provided an economical and efficient method for the removal of antibiotics in the future.

Electronic structure and oxygen vacancy tuning of Co & Ni co-doped W18O49 nanourchins for efficient TEA gas sensing

Inducing oxygen vacancies in metal oxides by dual doping metal ions is the key to modulating their electronic structure and designing highly sensitive noble metal-free materials for detecting hazardous toxic gases. This study reports nickel (Ni) and cobalt (Co) co-doping in W18O49 crystal lattices leads to electronic structure modulation and generates oxygen vacancies to highly activate the redox capability and catalytic efficacy of the urchin-like W18O49 sensor toward triethylamine (TEA) gas species. The electronic structure modulations and physisorption interactions between TEA molecules and W18O49 and/or Co&Ni co-doped W18O49 nanourchins were calculated by density functional theory (DFT). The experimental results and DFT calculations confirmed more significant charge transfers due to bandgap excitation and reactivity of TEA with Co&Ni co-doped W18O49 verifying their strong binding interactions. Electrons move from lattice oxygen to surface O2 molecules through co-doped cations-induced oxygen vacancies, which provide active sites and form surface superoxide and peroxide species incorporated into the sensing materials surface. Benefiting from the high specific surface area, abundant active sites, and faster electron/charge transport capability, the optimized 2 %Ni-doped W18O49, and 1 %Co&2%Ni co-doped W18O49 nanourchins exhibited excellent sensitivity towards TEA gas molecules. The sensing response of Co&Ni-W18O49 (Ra/Rg = 156) is higher than Ni-W18O49 (Ra/Rg = 114) and W18O49 (Ra/Rg = 76) at 250 °C, fast response/recovery (16/13), and superior selectivity. The XRD and XPS results combining the DFT calculations verify the improved sensitivity due to the synergistic modulation of electronic structure, which paws a friendly strategy for enriching the free electronics to design cost-effective gas sensors.

Ceria and gold co-decorated porous MoS2@graphene nanocomposite electrochemical electrode integrated with smartphone-controlled microstation for simultaneous dual metal ions detection

Continuous increase in release of toxic metals into ecosystem posed a threat to public ecology, leading to demand for the portable monitoring system to control contamination source and monitor disease progression. Herein, ceria and gold co-decorated porous MoS2@graphene nanocomposite was synthesized to construct electrochemical chip and integrate with smartphone-controlled hand-held microstation for simultaneous detecting Zn(II) and Cu(II). Concretely, MoS2 nanosheets coated polyimide were firstly laser-induced into 3D frame-structured MoS2/graphene with abundant oxygen-containing groups and active breaking edges, thereby accelerating the electron transfer and improving the absorptivity and reductive affinity for divalent ions. Double electro-deposition of ceria and gold provide vast oxygen vacancies for sensing, and Ce(III)/Ce(IV) cycle inhibit the recombination of electrons and holes, prolonging the life of carriers to enhance its electro-conductibility. The hydroxylation of ceria under acidic conditions is favorable for ions adsorption. Benefitting from synergetic effect among materials, the smartphone-controlled sensing system exhibits high sensitivity and low detection limit for Cu(II) of 2.8 ppt and Zn(II) of 103.6 ppt. Low energy barrier of target plating/stripping kinetics were also substantiated via calculating activation energy upon composite using Arrhenius formula. Furthermore, its outstanding flexibility, reusability, and anti-interference performance was verified, indicating the potential implementation possibilities in complex environment.

Hard and Soft Acid and Base (HSAB) Engineering for Efficient and Stable Sn‐Pb Perovskite Solar Cells

AbstractRegulation of Lewis acid‐base adduct intermediate is more critical for the dual metal ions of Sn2+ and Pb2+ than for the single metal ion such as Pb2+ in preparing high quality perovskite films. It has been reported here that the photovoltaic performance of Sn‐Pb alloyed perovskite solar cells is dependent on the interaction between metal ions and Lewis base additives. Urea and thiourea are selected as an O‐ and a S‐donor, respectively, which is used as an additive in the precursor solution including equimolar SnI2 and PbI2 together with organic iodides of formamidinium iodide and methylammonium iodide, forming a nominal composition of FA0.5MA0.5Pb0.5Sn0.5I3. Open‐circuit voltage (Voc) is increased while maintaining short‐circuit photocurrent density (Jsc) after the addition of urea. On the other hand, both Jsc and Voc are simultaneously increased by adding thiourea, leading to a considerable increase in power conversion efficiency from 14.58% (control) to 18.59%. A strong interaction between the relatively soft Sn2+, compared to Sn4+, and the soft sulfur in thiourea, associated with hard and soft acid and base theory, suppresses effectively a disproportionation reaction of 2Sn2+→ Sn4+ + Sn0, which results in a substantial enhancement of carrier lifetime and consequently photovoltaic performance.

In situ Electroactivated Fe‐NiOOH Nanoclusters on Carbon Quantum Dots for Efficient Large‐Scale Oxygen Production

The sluggish kinetics of oxygen evolution reaction (OER) seriously limits the development of water‐based energy devices due to the inevitable loss of activity at high current electrolysis. Herein, an in situ activation of the electrocatalyst of dual metal ions on carbon quantum dots (Fe‐NiOOH/CQDs) for the scalable oxygen production is reported. Through alternating the potential‐determining step and averaging energy barrier distributions of OER, Fe‐NiOOH/CQDs show excellent intrinsic OER performance with an extremely low Tafel slope of 35 mV dec−1 and the overpotential of 199 mV@10 mA cm−2. Meanwhile, the hydrophilicity and aerophobicity of Fe‐NiOOH/CQDs facilitate the rapid OH− diffusion and O2 detachment, resulting in an outstanding kinetics for large‐scale oxygen production. With an overpotential of 450 mV@1000 mA cm−2 and ultrahigh turnover frequency of 5.4 s−1, it is superior to most of the reported transitional‐metal‐based electrocatalysts. Thereby, a water splitting electrolyzer with Fe‐NiOOH/CQDs anode is assembled to demonstrate the promising reality.

A NASICON‐typed Na4Mn0.5Fe0.5Al(PO4)3 cathode for low‐cost and high‐energy sodium‐ion batteries

AbstractDeveloping low‐cost and high‐voltage manganese (Mn)‐based Na superionic conductor (NASICON) cathode materials have attracted extensive interest. The low capacity and cycling instability of Na4MnAl(PO4)3 (NMAP), however, limits its performance in sodium‐ion batteries (SIBs). Herein, a binary Na4Mn0.5Fe0.5Al(PO4)3 (MNFAP) is fabricated to ease the structural instability and, in turn, deliver an improved reversible capacity of 102 mAh g−1 at 0.1 C and a high energy density of 287.7 Wh kg−1. The synergistic interaction of Fe and Mn in Na4Mn0.5Fe0.5Al(PO4)3/C composite leads to a one‐phase solid‐solution reaction mechanism with high structural reversibility. Theoretical calculations have also been performed to explain the upshifted voltage platform of both Fe2+/Fe3+ and Mn3+/Mn4+ redox potentials. The rational design of NASICON‐type cathodes by regulating their composition with dual metal ions provides new perspectives for developing high‐performance SIBs.

Dual metal ions and water molecular pre-intercalated δ-MnO2 spherical microflowers for aqueous zinc ion batteries

Layered δ-MnO2 is a promising cathode material for aqueous zinc ion batteries (AZIBs) due to its high theoretical capacity, high operating voltage and low cost. However, the dissolution of MnO2 and the disproportionation of Mn3+ will lead to irreversible reaction and serious structural degradation of the material during cycling process. In this work, the Al3+ pre-intercalated K0.27MnO2·0.54H2O was prepared by a one-step hydrothermal method with citric acid as the complexing agent and weak reducing agent. Based on the pillars of bimetallic ions K+, Al3+ and water, the framework and interlayer of δ-MnO2 is stabilized. Besides, a certain amount of Al3+ facilitates the increase of crystal water compared with the pure K0.27MnO2·0.54H2O, which is not only conducive to promote the construction of porous and loose 3D morphology, but also beneficial to improve the stability of layered structure and accelerate the migration rate of zinc ions. Contributed to the dissolution/deposition reaction mechanism combined with H+/Zn2+ co-insertion/co-extraction mechanism, it has achieved the high capacity with the maximum reversible specific capacity of 269.5 mAh g−1 at 0.5 A g−1 and excellent stability with 205.8 mAh g−1 even after 300 cycles in Zn//Al-KMO battery.

An innovative trimetallic-MOF mediated catalytic cleavage activity of FAM tagged Ag10/T-rich DNAzyme as an ultra-sensitive and selective fluorescent biosensor for subsequent recognition of Ag+ and Hg2+ ions

In this work, specific and sensitive recognition of the dual metal ions (Ag+ & Hg2+) through the FAM tagged Ag10/T-rich DNAzyme mediated Trimetallic-MOF (Ni/Zn with K3[Co (CN)6]) as a biochemical sensing platform. Interestingly, the fluorescenceprobe of the FAM tagged specific Ag10/T-rich DNAzyme, and the Trimetallic-MOF demonstrated excellent analytical response towards subsequent recognition of the Ag+ & Hg2+ ions compared to the other coexisting targets. More precisely, the silver enzyme oligomer (EO) and FAM tagged thymine rich substrate oligomer (SO) were hybridized to form the Ag10/T-rich DNAzyme structure. When the Ag+ ion is induced into the Trimetallic-MOF with the FAM tagged Ag10/T-rich DNAzyme complex caused higher efficient internal catalytic cleavage at RNA site of FAM tagged substrate oligomer (SO). The released FAM tagged T-rich SO sequence was adsorbed on the Trimetallic-MOF surface through π-π stacking and electrostatic interactions, which diminished (Turn-OFF) the fluorescent signal. Surprisingly, the subsequent addition of the Hg2+ ions into the above-quenched system (Trimetallic-MOF/cleaved FAM tagged SO, and EO with Ag+) resulted in an enhancement of the fluorescence intensity (Turn-ON) due to the creation of the double-strand structure (T-Hg2+-T). By utilizing this sensor, susceptible and discriminating recognition of the Ag+ and Hg2+ ions is attained through the subsequent processes of catalytic cleavage of the DNAzyme and the FRET mechanism. As a result, the proposed biosensor achieved low detection limits of Ag+ (0.29 nM) and Hg2+ (0.10 nM), respectively. The utility of the developed fluorescence biosensor was established due to the subsequent recognition of the Ag+ and Hg2+ in actual water samples with satisfactory regaining and good reproducibility.

Nitrogen-Doped Carbon Quantum Dot-Anchored Hydrogels for Visual Recognition of Dual Metal Ions through Reversible Fluorescence Response

Nitrogen-Doped Carbon Quantum Dot-Anchored Hydrogels for Visual Recognition of Dual Metal Ions through Reversible Fluorescence Response

Development of novel blue emissive carbon dots for sensitive detection of dual metal ions and their potential applications in bioimaging and chelation therapy

In recent years, there has been an increased interest in the use of fluorescent carbon dots (C-dots) as an alternative to toxic synthetic organic dyes in live cell imaging, medical diagnostics and other diverse biomedical applications. In the present work, highly fluorescent C-dots have been prepared from commercially available peptic digest of animal tissue, without using any additional chemical reagent for surface functionalization. The synthesized C-dots are monodispersed nanomaterials with hydroxyl, carboxyl and amino surface functionalities and remain stable in high ionic strength media and over a wide range of pH. They exhibit a strong blue fluorescence upon excitation at 350 nm with a high quantum yield of 61%. The potential use of these C-dots as fluorescent nanoprobe for specific metal ions (Cu2+ and Hg2+) detection through chelation, radical scavenging and cellular imaging has been investigated. These highly fluorescent labels show rapid cellular internalization without hampering cellular integrity. Cell proliferation assay demonstrates that these C-dots have minimal cell toxicity even at a high concentration of 3 mg/mL. They show significant quenching on incubation with cells pretreated with Cu2+ and Hg2+ ions. They also show rapid exocytosis from cells showcasing their high potential for chelation therapy. Thus, this study offers a scalable synthesis approach for highly fluorescent and bio-compatible C-dots from a cost-effective precursor, which can be used for specific metal ions detection and their removal from cells through chelation via exocytosis. They can also be used as an alternate to synthetic organic dyes for fluorescence-based cell-imaging.

Highly sensitive and selective colorimetric detection of dual metal ions (Hg2+ and Sn2+) in water: an eco-friendly approach.

Application of an alliin-based precursor for the synthesis of silver nanoparticles (Ag NPs) which is an emerging, reliable and rapid sensor of heavy metal ion contaminants in water is reported here. The Ag NPs were characterized by using UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy analysis techniques. The Ag NPs simultaneously and selectively detect Hg2+ and Sn2+ ions from aqueous solution. The sensitivity and selectivity of the prepared Ag NPs towards other representative transition-metal ions, alkali metal ions and alkaline earth metal ions were also studied. For more precise evidence, a density functional theory study was carried out to understand the possible mechanism and interaction in the detection of Hg2+ and Sn2+ by Ag NPs. The limits of detection for Hg2+ and Sn2+ ions were found as 15.7 nM and 11.25 nM, respectively. This assay indicates the possible use of garlic extract-synthesized Ag NPs for sensing Hg2+ and Sn2+ in aqueous solution very significantly. So, the simple, green, eco-friendly and easy method to detect the dual metal ions may further lead to a potential sensor of heavy metal ion contaminants in water of industrial importance.