Penicillamine Research Articles

Revaluation of copper(II)-Schiff base complex for sensing of d-penicillamine and development of a molecular logic gate: A combined approach

d-penicillamine (D-PA) being a tri-functional organic compound (thiol, amine, and carboxylic acid) is used as a chelating drug for many serious diseases like Wilson’s disease. Due to its serious adverse effects, regular monitoring of blood and urine for D-PA is required during the clinical application of the drug. The dye-containing Cu(II)-Schiff base complex is revisited for easy monitoring of D-PA and the development of a new molecular logic gate through extensive studies. Revaluation is carried out in light of extensive experimental evidence and theoretical rationalization which help to achieve the target. The synthesized Cu(II)-salicylaldehyde rhodamine B hydrazone complex is characterized through FTIR, NMR, Mass spectrometry, UV–Vis, and fluorescence titrations. The crystal structure of the complex is optimized through DFT studies and found distorted square planar. Calculations of Frontier Molecular Orbitals (FMOs) assist to understand the electronic and optical properties of the complex. The recognition of D-PA (LOD = 2.60 × 10-8 M) is executed both colorimetrically and fluorometrically through the “Turn-off” mechanism. The NAND-type molecular logic gate has been developed.

DFT study of D-Penicillamine adsorption on Al and Ga doped boron nitride (Al-B11N12 and Ga-B11N12) nanoclusters as drug delivery agents

A comprehensive computational investigation was performed in this study on the adsorption of a penicillamine (PCA) molecule as drug onto Al- and Ga-doped B12N12 nanoclusters in aqueous and chloroform environments, using density functional theory calculations. The main aim was to evaluate the capability of the nanocluster in drug delivery applications. The PCA molecule interacts effectively with Al- and Ga-doped clusters via its four nucleophilic sites: amine, carbonyl, hydroxyl, and thiol. Using the computational results, the most stable adsorption complexes were obtained when the PCA molecule adsorbs through its amine group with −4.75 and −4.67 eV adsorption energies for Al-B11N12 and Ga-B11N12 nanocages, respectively. The adsorption of the PCA molecule decreases the HOMO–LUMO gaps and the global hardness of the doped clusters, which corroborated increases in reactivity of the considered clusters for drug delivery purpose. Our computational studies exhibit that Al and Ga atoms doping improves the drug delivery capacity of B12N12 nanoclusters.

The Combined Effect of Hg(II) Speciation, Thiol Metabolism, and Cell Physiology on Methylmercury Formation by Geobacter sulfurreducens.

The chemical and biological factors controlling microbial formation of methylmercury (MeHg) are widely studied separately, but the combined effects of these factors are largely unknown. We examined how the chemical speciation of divalent, inorganic mercury (Hg(II)), as controlled by low-molecular-mass thiols, and cell physiology govern MeHg formation by Geobacter sulfurreducens. We compared MeHg formation with and without addition of exogenous cysteine (Cys) to experimental assays with varying nutrient and bacterial metabolite concentrations. Cysteine additions initially (0-2 h) enhanced MeHg formation by two mechanisms: (i) altering the Hg(II) partitioning from the cellular to the dissolved phase and/or (ii) shifting the chemical speciation of dissolved Hg(II) in favor of the Hg(Cys)2 complex. Nutrient additions increased MeHg formation by enhancing cell metabolism. These two effects were, however, not additive since cysteine was largely metabolized to penicillamine (PEN) over time at a rate that increased with nutrient addition. These processes shifted the speciation of dissolved Hg(II) from complexes with relatively high availability, Hg(Cys)2, to complexes with lower availability, Hg(PEN)2, for methylation. This thiol conversion by the cells thereby contributed to stalled MeHg formation after 2-6 h Hg(II) exposure. Overall, our results showed a complex influence of thiol metabolism on microbial MeHg formation and suggest that the conversion of cysteine to penicillamine may partly suppress MeHg formation in cysteine-rich environments like natural biofilms.

Analysis of risk factors for neurological symptoms in patients with purely hepatic Wilson’s disease at diagnosis

ObjectiveTo analyze and explore the risk factors for neurological symptoms in patients with purely hepatic Wilson's disease (WD) at diagnosis.MethodsThis retrospective study was conducted at the First Affiliated Hospital of the Guangdong Pharmaceutical University on 68 patients with purely hepatic WD aged 20.6 ± 7.2 years. The physical examinations, laboratory tests, color Doppler ultrasound of the liver and spleen, and magnetic resonance imaging (MRI) of the brain were performed.ResultsThe elevated alanine transaminase (ALT) and aspartate transaminase (AST) levels and 24-h urinary copper level were higher in the purely hepatic WD who developed neurological symptoms (NH-WD) group than those in the purely hepatic WD (H-WD) group. Adherence to low-copper diet, and daily oral doses of penicillamine (PCA) and zinc gluconate (ZG) were lower in the NH-WD group than those in the H-WD group. Logistic regression analysis showed that insufficient doses of PCA and ZG were associated with the development of neurological symptoms in patients with purely hepatic WD at diagnosis.ConclusionThe development of neurological symptoms in patients with purely hepatic WD was closely associated with insufficient doses of PCA and ZG, and the inferior efficacy of copper-chelating agents. During the course of anti-copper treatment, the patient's medical status and the efficacy of copper excretion should be closely monitored.

Ultrasensitive colorimetric and fluorescent dual-readout assay for D-penicillamine based on the chloride boosted oxidative ability of copper ions

Dual-readout protocols with two signal transduction channels can significantly improve the detection precision and diversity. In contrast to the previous tedious and time-consuming preparation of two response materials, a convenient and commercially available small molecule o-Phenylenediamine (OPD)-based dual-mode system was developed for the ultrasensitive detection of D-penicillamine (D-PA). Fortunately and interestingly, it is demonstrated that chloride ions (Cl−) could largely enhance the oxidative ability of copper ions (Cu2+) and improve the reaction rate and efficiency of the Cu2+-OPD system, leading to the boosted colorimetric and fluorescent signals and shorter reaction time. Meanwhile, D-PA could strongly bind with Cu2+ to form a stable Cu2+-D-PA complex, thereby inhibiting the aforementioned oxidation process and exhibiting decrease of absorbance values and fluorescence intensity. Inspired by the excellent analytical performance, an “INH” molecular logic gate was devised by employing Cl− and D-PA as the inputs, and the dual-mode strategy has been successfully employed to probe D-PA in tablets and human serum samples. Such cost-effective yet efficacious analytical tool not only improve the sensing performance of the Cu2+-OPD reaction system, but also enhance the detection sensitivity for D-PA and promote the application and development of OPD-based reactions.

Nitrogen-doped Ti3C2 MXene quantum dots as an effective FRET ratio fluorometric probe for sensitive detection of Cu2+ and D-PA

In this work, a ratiometric fluorescence sensing platform was established to detect Cu2+ and D-PA (d-penicillamine) based on nitrogen-doped Ti3C2 MXene quantum dots (N-MODs) that was prepared via a simple hydrothermal method and exhibited strong fluorescent and photoluminescence performance as well as excellent stability. Since the oxidation reaction between o-phenylenediamine (OPD) and Cu2+ induced the formation of 2,3-diaminophenazine (ox-OPD) which not only can emerge an emission peak at 570 nm, but also inhibit the fluorescence intensity of N-MQDs at 450 nm, a ratiometric reverse fluorescence sensor via fluorescence resonance energy transfer (FRET) was designed to sensitively detect Cu2+, where N-MQDs acted as energy donor and ox-OPD as energy acceptor. More importantly, another considerably interesting phenomenon was that their catalytic oxidation reaction can be restrained in the presence of D-PA because of the coordination of Cu2+ with D-PA, further triggering the obvious changes in ratio fluorescent signal and color, thus a ratiometric fluorescent sensor of determining D-PA was proposed also in this work. After optimizing various conditions, the ratiometric sensing platform showed rather low detection limits for Cu2+ (3.0 nM) and D-PA (0.115 μM), coupled with excellent sensitivity and stability.

High-Performance Formaldehyde Sensing Using Paper-Based Fluorescent Copper Nanoclusters

Highly sensitive detection of formaldehyde (FA) is of great importance to protect human health against its adverse effect. Herein, we constructed copper nanoclusters (Cu NCs) with strong luminescence capable of rapid, sensitive, and visual detection of FA, which was self-assembled using D-penicillamine (DPA) as the protecting ligand. Common physical measurements were carried out to analyze the as-fabricated samples (DPA-Cu NCs). Experimental results revealed its strong red fluorescence (FL), large Stokes shift, and a long fluorescence lifetime. Furthermore, DPA-Cu NCs presented self-assembled aggregation-induced emission (SAIE) property and achieved a fluorescence quantum yield (FLQY) as high as 76.26% in the solid state. Notably, FA could quench the fluorescence of Cu NCs effectively. The possible quenching mechanism was attributed to static quenching. Moreover, a paper-based visual sensor was built by immobilizing the DPA-Cu NCs probe on the filter paper, which can achieve on-site detection of FA.

Detection and Bioimaging of Glutathione in Cells via a Turn-On Near-Infrared Fluorescent Nanoprobe Composed of Ag2S Quantum Dots and CoOOH Nanosheets

The variations of the microenvironment in cells are always associated with changes in the concentrations of some active species. However, visual detection of these species is still a challenge. In this work, near-infrared (NIR)-emitting fluorescent Ag2S quantum dots (Ag2S QDs) were synthesized via a rapid microwave reaction under normoxic conditions, which were utilized as sensitive fluorescent nanoprobes in sensing and bioimaging of glutathione (GSH) combined with CoOOH nanosheets (CoOOH NSs). The negatively charged Ag2S QDs can easily and effectively attach to the surface of CoOOH NSs to form the Ag2S QD/CoOOH nanoprobe through electrostatic interactions, accompanied by the quenching of the fluorescence of Ag2S QDs at 685 nm via the inner-filter effect (IFE). However, upon the addition of GSH, the fluorescence of Ag2S QDs was recovered due to the reduction of CoOOH NSs into Co2+ by GSH. Meanwhile, the fluorescent emission wavelength shifts slightly, which may result from the ligand exchange reaction between GSH and d-penicillamine (DPA) to form comodified Ag2S QDs. Based on the low toxicity and high tissue penetration depth of the NIR fluorescence of the Ag2S QDs and the good biocompatibility of CoOOH NSs, the nanoprobe composed of Ag2S QDs and CoOOH NSs was successfully applied in bioimaging, which can distinguish the normal cells and cancer cells, the semiquantitative content of endogenous and exogenous GSH. The as-developed strategy not only provides a simple, convenient, cost-effective, and rapid platform for the diagnosis of clinical diseases related to GSH but shows great prospects in fluorescence-assisted surgery.

Copper nanoclusters stabilized by D-penicillamine for ultrasensitive and visual detection of oxytetracycline

Copper nanoclusters (DPA@CuNCs) with red fluorescence were successfully synthesized by a one-step method based on D-penicillamine (DPA), which acted not only as a reducing agent but also as a stabilizer. The products were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, particle-size analysis, ultraviolet–visible spectrophotometry, and fluorescence spectrometry. When the excitation wavelength was 280 nm, DPA@CuNCs emitted bright red fluorescence at 640 nm with a fluorescence quantum yield of 5.8 %. Due to the inner filter effect, oxytetracycline (OTC) effectively quenched the fluorescence of DPA@CuNCs, and then DPA@CuNCs were applied to the trace detection of OTC. The method showed a good linear range for OTC from 5 to 60 μmol/L, with a detection limit of 0.026 μmol/L and a correlation coefficient R2 of 0.9983. Moreover, a paper-based sensor for the visual detection of OTC has been developed, which can conveniently and rapidly distinguish the concentration ranges of OTC through the color changes of the test papers.

Effect of Copper Chelators via the TGF-β Signaling Pathway on Glioblastoma Cell Invasion.

Glioblastoma multiforme (GBM) is a fast-growing and aggressive type of brain cancer. Unlike normal brain cells, GBM cells exhibit epithelial-mesenchymal transition (EMT), which is a crucial biological process in embryonic development and cell metastasis, and are highly invasive. Copper reportedly plays a critical role in the progression of a variety of cancers, including brain, breast, and lung cancers. However, excessive copper is toxic to cells. D-penicillamine (DPA) and triethylenetetramine (TETA) are well-known copper chelators and are the mainstay of treatment for copper-associated diseases. Following treatment with copper sulfate and DPA, GBM cells showed inhibition of proliferation and suppression of EMT properties, including reduced expression levels of N-cadherin, E-cadherin, and Zeb, which are cell markers associated with EMT. In contrast, treatment with copper sulfate and TETA yielded the opposite effects in GBM. Genes, including TGF-β, are associated with an increase in copper levels, implying their role in EMT. To analyze the invasion and spread of GBM, we used zebrafish embryos xenografted with the GBM cell line U87. The invasion of GBM cells into zebrafish embryos was markedly inhibited by copper treatment with DPA. Our findings suggest that treatment with copper and DPA inhibits proliferation and EMT through a mechanism involving TGF-β/Smad signaling in GBM. Therefore, DPA, but not TETA, could be used as adjuvant therapy for GBM with high copper concentrations.

Seven decades of clinical experience with Wilson's disease: Report from the national reference centre in Poland.

Wilson's disease (WD) is a rare autosomal recessive disorder causing excessive copper deposition and a spectrum of manifestations, particularly neurological and hepatic symptoms. We analysed the clinical characteristics of patients with WD admitted to the country's only reference centre, which provided long-term care to most adult patients in Poland over seven decades (pre-1959 to 2019). Electronic prospective data collection began in the 2000s and, for prior years, medical records were analysed retrospectively. Demographic and clinical characteristics, treatment and outcomes were analysed by decade of diagnosis. Life-years lost were estimated in patients with WD compared with the general population. Kaplan-Meier curves were used for a time-to-death analysis using 2000-2009 as a reference. In total, 929 patients were analysed. The number of patients increased from 21 before 1959 to 315 for 2000 to 2009 period. Mostly males were diagnosed before the 1990s, but the numbers of female patients diagnosed increased thereafter. Initially, most patients presented with neurological manifestations; however, the incidence of hepatic manifestations and asymptomatic presentations increased over time as patients were diagnosed early and consequently were more independent at diagnosis. Fewer Kayser-Fleischer rings were detected recently. Prior to 1970, patients were treated with D-penicillamine (DP); however, since the introduction of zinc, both therapies have been used as often. Since the 1990s, switches between DP and zinc were recorded in 6%-7% of patients. Consistent improvement in survival has been observed over the years. This is the largest cohort of patients with WD reported in Poland, with the longest follow-up. Earlier diagnosis and prognosis have improved over seven decades.

Novel copper complexes-polyurethane composites that mimics anti-inflammatory response

Copper is a trace element of biological significance that can form complexes with several thiol containing compounds which can be used as filler in biomedical polyurethanes. In this work, segmented polyurethanes (SPUs) were synthesized with thiol containing compounds as chain extenders including d-penicillamine (DP), l-penicillamine (LP), l-cysteine (LC) and reduced glutathione (GR). Then, the synthesized polyurethane was filled with copper chelates based on the same chain extenders. Evidence of free thiol containing chain extender in polyurethane was not observed by FTIR and Raman but EDX provided evidence of sulfur in the unfilled polyurethane and copper and sulfur in their composite. DSC and DRX showed the semi-crystalline nature of the polyurethanes which provided good mechanical properties, especially to those prepared with DP. The Tg of the PCL determined by DMA shifted toward higher temperatures by the addition of copper complexes while TGA studies showed that the thermal degradation was slightly improved when LCCu and GRCu complex were added. Macrophage viability was observed in all composition studied after longer times of extraction (72 h) and dilutions (1:2 to 1:32) but remarkably high in those prepared with LCCu and GRCu. The anti-inflammatory response was proved in LC and GR copper complex filled polyurethanes as IL-4 and IL-10 increased with time while IL-1β and TNF-α were reduced.

Ratiometric Detection of Al Based on the Mixing of D‐penicillamine‐Functionalized Copper Nanoclusters with Pyridoxal 5’‐phosphate

AbstractThe excess accumulation of nonessential Al3+ in the human body can cause serious health problems, thus there is significant interest in the detection of Al3+. A new ratio fluorescent probe (RF‐probe) based on the mixing of red‐emitting D‐penicillamine (DPA) stabilized copper nanoclusters (DPA‐CuNCs) with pyridoxal 5’‐phosphate (PLP) was designed for sensitive and selective determination of Al3+. The −CHO group of PLP is expected to form an imine linkage with the free −NH2 group available of the DPA on the surface of DPA‐CuNCs. The content of Al3+ could be mensurated by the as‐prepared RF‐probe with a linear response in the range of 1.33–46.67 μmol ⋅ L−1, and corresponding limit of detection (LOD) was calculated to be 0.33 μmol ⋅ L−1. Moreover, the RF‐probe was successfully extended to the assay of Al3+ in aluminum carbonate chewing tablets, baking powder, pond water and drink water with satisfactory results compared to the standard atomic absorption spectroscopy (AAS).

Outcome of Wilson’s disease in Bangladeshi children: a tertiary center experience

BackgroundWilson disease (WD) is an inherited disorder of copper metabolism commonly involving the liver, cornea, and brain. Its incidence is increasing day by day worldwide. Early diagnosis and prompt treatment are the key for best outcome.Material and methodsA cross-sectional descriptive study was done from January 2014 to December 2019. Sixty children of both genders between 3 and 18 years were diagnosed by clinical and laboratory profile meeting selected criteria.ResultsMean age was 8.42 ± 2.6 years and male female ratio was 1.5:1. Consanguinity of marriage was found in 38.3% cases. Seventy percent of cases were hepatic, 16.7% were neuropsychiatric, 5.0% were hepatic with neuropsychiatric, and 8.3% cases were manifested asymptomatically. Asymptomatic and hepatic WD were reported between 3 and 10 years and most of the neuropsychiatric and hepatic with neuropsychiatric manifested after 10 years of age. More than 50% cases improved, a little more than 20% children died, 18.4% were unchanged and 6.6% were hepatic added neuropsychiatric manifestations. Most of the asymptomatic (100%) and hepatic (61.9%) cases improved. High mortality was found with 76.9% cases of acute liver failure (ALF), 7.7% case of chronic liver disease (CLD) and 25% cases of CLD with portal hypertension (CLD and PH). Most of the neuropsychiatric cases (90.0%), and approximately two-third (66.6%) of hepatic with neuropsychiatric cases remained unchanged. Neuropsychiatric manifestations were added in 15.4% cases of CLD and 25% cases of CLD with PH patient. The treatment was well tolerated in 66% children without any side effects. Low WBC (6.3%) and platelet count (4.3%), vomiting (6.3%), anorexia (4.3%), loss of taste (4.3%), rash (4.3%), and proteinuria (2.1%) were found in few cases.ConclusionMajority of the children were presented with hepatic manifestations. More than half of patients with WD treated by D-penicillamine (DP) were improved. Significant mortality was found in acute liver failure whereas neuropsychiatric presentations had persistent abnormalities. No major side effects of DP was observed in most of the cases. Early diagnosis and prompt treatment were crucial for better outcome.

Transformation of a short-term boar semen extender into a long-term boar semen extender by using penicillamine

This study aimed to convert a short-term semen extender into a long-term semen extender by adding penicillamine (PEN). Semen samples were collected from six boars, diluted at a concentration 3 × 10<sup>9</sup> spermatozoa/100 ml, and divided into eight groups as follows: BTS, Merck III<sup>®</sup>, Androstar<sup>®</sup> Plus, PEN 0.125 mM, PEN 0.25 mM, PEN 0.5 mM, PEN 1.0 mM, PEN 2.0 mM. All the diluted semen samples were stored at 18 °C and were examined for progressive motility, viability, acrosome integrity, pH and osmolarity on days 0, 1, 3, 5 and 7 after storage. The level of the total anti-oxidative capability (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were also measured for antioxidant activities. Fertility tests on a commercial pig farm was also conducted. On days 0, 1 and 3 of storage, no statistically significant differences in all the parameters among the extenders was observed. On day 5, the semen diluted with PEN at a concentration of 0.25 mM and Androstar<sup>®</sup> Plus could maintain progressive motility reach of 70.0% and 76.0%, respectively (P < 0.01). On day 7, the semen diluted with PEN at a concentration of 0.25 mM maintained progressive motility (70.0%) and acrosome integrity (85.7%) which is comparable to long-term semen extenders (Androstar<sup>®</sup> Plus) (P < 0.01). For the antioxidant activities, the level of the T-AOC, SOD and MDA varied depended on the PEN concentrations . The results of the fertility test were not different among the groups. To conclude, adding PEN at 0.25 mM in the BTS extender is able to transform a short-term semen extender into a long-term extender.

Response surface methodology optimization for the synthesis of N, S-codoped carbon dots and its application for tetracyclines detection.

In this study, using a convenient one-pot microwave-assisted method, we rapidly fabricated a N, S-codoped fluorescent carbon dots (NSCDs) through using citric acid (CA) and d-penicillamine (DPA) for the detection of tetracyclines (TC). To rapidly and efficiently optimize the various synthesis parameters and significantly decrease the number of experimental runs, the effect of the synthesis factors on quantum yield (QY) by NSCDs was implemented through means of response surface methodology (RSM). The as-synthesized NSCDs presented superior photoluminescence stability with a strong quantum yield (QY) of 91.55% under optimal conditions, which was consistent with the predicted value using RSM. The fluorescence intensity of the NSCDs could be quenched effectively after adding TC by the inner filter effect (IEE) and photoinduced electron transfer (PET). Thus, the determination of TC by using NSCDs as a facile fluorescent probe was constructed in the range of 0.2-70μM with a limit detection of 0.072μM. Moreover, this detection approach has been utilized to detect TC in actual samples with satisfactory results.

D-Penicillamine Reveals the Amelioration of Seizure-Induced Neuronal Injury via Inhibiting Aqp11-Dependent Ferroptosis.

Repetitive seizures, a common phenomenon in diverse neurologic conditions such as epilepsy, can undoubtedly cause neuronal injury and our prior work reveals that ferroptosis is a contributing factor of neuronal damage post seizure. However, there is no drug available in clinical practice for ameliorating seizure-induced neuronal impairment via targeting ferroptosis. Our present work aimed to explore whether D-penicillamine (DPA), an originally approved drug for treating Wilson’s disease, inhibited neuronal ferroptosis and alleviated seizure-associated brain damage. Our findings revealed that DPA remarkably improved neuronal survival in kainic acid (KA)-treated mouse model. Furthermore, ferroptosis-associated indices including acyl-coA synthetase long chain family member 4 (ACSL4), prostaglandin-endoperoxide synthase 2 (Ptgs2) gene and lipid peroxide (LPO) level were significantly decreased in KA mouse model after DPA treatment. In a ferroptotic cell death model induced by glutamate or erastin, DPA was also validated to evidently suppress neuronal ferroptosis. The results from RNA-seq analysis indicated that Aqp11, a gene coding previously reported channel protein responsible for transporting water and small solutes, was identified as a molecular target by which DPA exerted anti-ferroptotic potential in neurons. The experimental results from in vivo Aqp11 siRNA transfer into the brain also confirmed that knockdown of Aqp11 abrogated the inhibitory effect of seizure-induced ferroptosis after DPA treatment, suggesting that the effects of DPA on ferroptosis process are dependent upon Aqp11. In conclusion, DPA can be repurposed to cure seizure disorders such as epilepsy.

Simultaneous Chemical Crosslinking of SnO2 and Perovskite for High‐Performance Planar Perovskite Solar Cells with Minimized Lead Leakage

SnO2‐based planar perovskite solar cells (PSCs) have attracted extensive attention owing to their simple structure and low‐temperature processing. However, the imperfect interface contact caused by surface defects and energy‐level mismatches greatly hinder the further improvement of the efficiency and stability of PSC. Herein, a multifunctional interfacial crosslinking agent D‐penicillamine (DPM) is introduced to improve the interface contact between SnO2 and upper perovskite. Through systematical analysis, it is found that the DPM used to modify SnO2 can simultaneously passivate the defects on the surface of SnO2 via esterification reaction, promote the charge extraction in perovskite by adjusting the interface energy‐level arrangement, and improve the quality of perovskite film by forming coordination bond with lead ions. These merits eventually assist DPM‐modified PSCs and achieve an impressive efficiency of 24.09%, whereas the controlled device only shows an efficiency of 22.44%. In addition, an unencapsulated DPM‐modified PSC exhibits better storage stability, thermal stability, and light stability than the controlled device, as well as in situ absorption capacity of leaked lead ions.

Metal-Organic frameworks encapsulated Ag Nanoparticle-Nanoclusters with enhanced luminescence for simultaneous detection and removal of Chromium(VI)

Metal nanoclusters (NCs) have emerged as a class of promising luminescent materials for sensing, but the low luminescence efficiency hindered their applications. In this work, highly luminescent composites were synthesized by encapsulating D-penicillamine (DPA) capped silver nanoparticle-nanoclusters (AgNP-NCs) into zeolitic imidazolate frameworks (ZIF-8) (denoted as AgNP-NCs@ZIF-8) and were applied for simultaneous detection and removal of chromium(Ⅵ). The photoluminescence intensity of the AgNP-NCs was enhanced by (66 ± 5) folds due to the confinement of ZIF-8 shell, and the lifetime was prolonged from (50.9 ± 1.8) ns to (15.9 ± 0.4) μs. More importantly, thanks to the strong luminescent property of AgNP-NCs and porous structure of the ZIF-8 shell, the AgNP-NCs@ZIF-8 composites not only allowed for the detection of Cr(Ⅵ) as luminescent probe but also exhibited good adsorption capacity of Cr(Ⅵ). The luminescence intensity decreased linearly with Cr(Ⅵ) concentration in the range of 40 to 400 μM, and the limit of detection was determined to be (23.5 ± 0.8) μM. They also exhibited high selectivity toward total chromium in various interfering metal ions and good performance in real water samples. These results indicated that AgNP-NCs@ZIF-8 could serve as an attractive candidate for simultaneous detection and removal of Cr(Ⅵ) in environmental monitoring and protection.

Construction of g-C3N4/Au/NH2-UiO-66 Z-scheme heterojunction for label-free photoelectrochemical recognition of D-penicillamine

The wide clinical application of d-penicillamine (D-PA) makes it inevitably accumulates in the environment, seriously threatening human health and the ecological environment. To better supervisory control D-PA, a highly sensitive and reliable photoelectrochemical (PEC) sensor based on gold nanoparticles (Au NPs) loaded on graphitic carbon nitride sheet and hexagonal NH2-UiO-66 composite (g-C3N4/Au/NH2-UiO-66) was synthesized. Tactfully using the strong bonding between D-PA and Au NPs and the effective carrier separation of Z-scheme heterojunction, the designed g-C3N4/Au/NH2-UiO-66 PEC sensor without an extra recognition unit exhibited a selective and sensitive photocurrent to D-PA. With the aid of UV diffuse reflectance spectra (UV-DRs), electron paramagnetic resonance (EPR) characterization, and free radical capture experiments, the electron transfer path of the PEC sensing system was deduced. The proposed g-C3N4/Au/NH2-UiO-66 PEC-based sensor achieved a low detection limit of 0.0046 μM (S/N = 3) with a wide linear response ranging from 10 nM to 400 μM. In addition, its good stability and selectivity also laid a good foundation for practical applications.