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1.
Sci Total Environ ; 864: 161156, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36572319

RESUMO

As a widely applied semiconductor nanomaterial, quantum dots (QDs) have drawn considerable interest. In this study, pumpkin and rice seedlings were hydroponically exposed to two core/shell CdSe/ZnS QDs coated with cysteamine (CdSe/ZnS-CA) and polyethylene glycol-carboxy (CdSe/ZnS-PEG-COOH) for 10 days to analyze their time-varying uptake, translocation, and transformation behaviors in plants. Both QDs were mainly adsorbed/absorbed by the roots in the particulate state, and more CdSe/ZnS-CA accumulated than CdSe/ZnS-PEG-COOH. For CdSe/ZnS-CA-treated plants, the Se and Cd concentrations (CSe and CCd) associated with the roots were 561 ± 75 and 580 ± 73 µg/g (dw) for rice and 474 ± 49 and 546 ± 53 µg/g (dw) for pumpkin, respectively, on day 10. For CdSe/ZnS-PEG-COOH-treated plants, the concentrations of Se and Cd associated with roots were 392 ± 56 and 453 ± 56 µg/g (dw) for rice and 363 ± 52 and 417 ± 52 µg/g (dw) for pumpkin, respectively. The surface charges and coatings significantly affected the accumulation of QDs at the beginning of exposure; however, the impaction decreased with time. The ratios between the Cd and Se concentrations (CCd/CSe) in the stems and leaves varied from those of the QD standards, indicating the transformation of the QDs in the exposure system. Se and Cd were more likely to translocate in CdSe/ZnS-PEG-COOH-treated plants than in CdSe/ZnS-CA-treated plants. The vertical translocation of Se was greater than that of Cd. Rice showed greater abilities of accumulation and translocation of Se and Cd from both QDs than pumpkin. These findings improve our understanding of the interference of QDs with plants and their environmental fate.


Assuntos
Compostos de Cádmio , Cucurbita , Oryza , Pontos Quânticos , Compostos de Selênio , Cádmio , Compostos de Zinco , Sulfetos
2.
Chemosphere ; 314: 137660, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36581122

RESUMO

Researchers have been enthusiastic about developing high-performance electrode materials based on metal chalcogenides for energy storage applications. Herein, we developed cupric ion-containing zinc sulfide (ZnS:Cu) nanoplates by using a solvothermal approach. The as-synthesized ZnS:Cu nanoplates electrode was characterized and analyzed by using XRD, SEM, TEM, EDS, and XPS. The binder-free flexible ZnS:Cu nanoplates exhibited excellent specific capacitance of 545 F g-1 at a current density of 1 A g-1. The CV and GCD measurements revealed that the specific capacitance was mainly attributed to the Faradaic redox mechanism. Further, the binder-free flexible ZnS:Cu nanoplates electrode retained 87.4% along with excellent Coulombic efficiency (99%) after 5000 cycles. The binder-free flexible ZnS:Cu nanoplates exhibited excellent conductivity, specific capacitance, and stability which are beneficial in energy storage systems. These findings will also open new horizons amongst material scientists toward the new direction of electrode development.


Assuntos
Excipientes , Zinco , Compostos de Zinco , Capacitância Elétrica
3.
Sensors (Basel) ; 22(24)2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36560314

RESUMO

Rapid and accurate detection of lethal volatile compounds is an emerging requirement to ensure the security of the current and future society. Since the threats are becoming more complex, the assurance of future sensing devices' performance can be obtained solely based on a thorough fundamental approach, by utilizing physics and chemistry together. In this work, we have applied thermal desorption spectroscopy (TDS) to study dimethyl methylophosphate (DMMP, sarin analogue) adsorption on zinc phthalocyanine (ZnPc), aiming to achieve the quantification of the sensing mechanism. Furthermore, we utilize a novel approach to TDS that involves quantum chemistry calculations for the determination of desorption activation energies. As a result, we have provided a comprehensive description of DMMP desorption processes from ZnPc, which is the basis for successful future applications of sarin ZnPc-based sensors. Finally, we have verified the sensing capability of the studied material at room temperature using impedance spectroscopy and took the final steps towards demonstrating ZnPc as a promising sarin sensor candidate.


Assuntos
Substâncias para a Guerra Química , Compostos Organometálicos , Substâncias para a Guerra Química/análise , Sarina , Compostos Organometálicos/química , Compostos de Zinco
4.
Langmuir ; 38(51): 15995-16003, 2022 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-36512759

RESUMO

In contrast to the hot-injection organometallic routes, synthesizing stable and highly luminescent core/shell nanocrystals with encapsulation of biocompatible groups through an aqueous route is a long-standing challenge. In recent years, relatively high quantum efficiency and unique properties of core/shell nanostructured materials (quantum dots) have contributed toward enhancement in sensing capability. The present work reports a facile aqueous synthesis process of core/shell CdSe/ZnS quantum dots (QDs) with encapsulation of glutathione (GSH). The optimal conditions for the synthesis of the most stable particles were ascertained, and the different experimental analyses suggest that the stable core/shell QDs in question have good crystallinity with a size around 4.7 nm with a shell thickness of 0.7 nm and a photoluminescence quantum yield of about 35%. Further, it is demonstrated that the as-synthesized material has great potential in detecting as low as 0.28 nM 3-nitro-l-tyrosine (3-NT), an important marker for oxidative stress, the level of which in our body signals several chronically diseased conditions. The enthalpy-driven interactions of CdSe/ZnS-GSH QDs with 3-NT were characterized through steady-state and time-resolved luminescence spectroscopy and isothermal microcalorimetry. The devised method of probing 3-NT was further validated with human serum samples. Thus, the proposed strategy may provide a protocol for selective determination of 3-NT under different pathological conditions.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Humanos , Pontos Quânticos/química , Compostos de Cádmio/química , Luminescência , Compostos de Selênio/química , Compostos de Zinco/química , Sulfetos/química , Água/química , Glutationa/química
5.
Int J Mol Sci ; 23(23)2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36499186

RESUMO

Based on the isolobal analogy of ZnCp (Cp = η5-C5H5) and ZnR (R = alkyl or aryl group) fragments with hydrogen atom and fragment [Zn(CO)2] with a CH2 carbene, the following complexes [(ZnCp)2{µ-Zn(CO)2}], 1, [(ZnPh)2{µ-Zn(CO)2}], 2, [(ZnPh){µ-Zn(CO)2}(ZnCp)], 3, [(ZnCp)2{µ-Zn2(CO)4}], 4, [(ZnPh)2{µ-Zn2(CO)4}], 5, [(ZnPh){µ-Zn(CO)2}2(ZnCp)], 6, [Zn3(CO)6], 7 and [Zn5(CO)10], 8, were built. These polynuclear zinc compounds are isolobally related to simple hydrocarbons (methane, ethane, cyclopropane and cyclopentane). They have been studied by density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) to compare the nature and topology of the Zn-Zn bond with previous studies. There are bond critical points (BCPs) between each pair of adjacent Zn centers in complexes 1-8 with Zn-Zn distances within the range 2.37-2.50 Å. The nature of the Zn-Zn bond in these complexes can be described as polar rather than pure covalent bonds. Although in a subtle way, the presence of different ligands and zinc oxidation states introduces asymmetry and polarity in the Zn-Zn bond. In addition, the Zn-Zn bond is delocalized in nature in complex 7 whereas it can be described as a localized bond for the remaining zinc complexes here studied.


Assuntos
Teoria Quântica , Zinco , Zinco/química , Compostos de Zinco/química , Hidrogênio , Ligantes
6.
Environ Sci Technol ; 56(23): 16831-16837, 2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36394535

RESUMO

Nanosized zinc sulfides (nano-ZnS) have size-dependent and tunable physical and chemical properties that make them useful for a variety of technological applications. For example, structural changes, especially caused by strain, are pronounced in nano-ZnS < 5 nm in size, the size range typical of incidental nano-ZnS that form in the environment. Previous research has shown how natural organic matter impacts the physical properties of nano-ZnS but was mostly focused on their aggregation state. However, the specific organic molecules and the type of functional groups that are most important for controlling the nano-ZnS size and strain remain unclear. This study examined the size-dependent strain of nano-ZnS synthesized in the presence of serine, cysteine, glutathione, histidine, and acetate. Synchrotron total scattering pair distribution function analysis was used to determine the average crystallite size and strain. Among the different organic molecules tested, those containing a thiol group were shown to affect the particle size and size-induced strain most strongly when added during synthesis but significantly reduced the particle strain when added to as-formed nano-ZnS. The same effects are useful to understand the properties and behavior of natural nano-ZnS formed as products of microbial activity, for example, in reducing environments, or of incidental nano-ZnS formed in organic wastes.


Assuntos
Nanopartículas , Compostos de Zinco , Compostos de Zinco/análise , Compostos de Zinco/química , Sulfetos/química , Nanopartículas/química , Tamanho da Partícula
7.
ACS Nano ; 16(11): 19053-19066, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36349982

RESUMO

The critical role of transition metal dyshomeostasis in Alzheimer's disease (AD) pathology poses demands of in vivo imaging for brain copper levels. Nanostructured probes afford prolonged retention time, increased accumulation, and enhanced photostability; however, their development for activatable photoacoustic (PA) imaging remains largely unexplored. We develop a principle of concept for activable PA imaging using in situ cation exchange of ultrathin zinc selenide (ZnSe) nanoplatelets for monitoring brain copper levels in AD mice. We start from quantitative modeling of optical absorption, time-resolved temperature field, and thermal expansion of copper selenide (CuSe) nanocrystals of different morphologies and reveal that ultrathin nanoplatelets afford substantial enhancement of near-infrared (NIR) absorption and PA pressures as compared to nanodots and nanoparticles. By tethering with a blood-brain barrier (BBB)-targeting peptide ligand, the ultrathin ZnSe nanoplatelet probe efficiently transports across the BBB and rapidly exchanges with endogenous copper ions, boosting activatable PA imaging of brain copper levels. We also demonstrate that the efficient exchange of ZnSe nanoplatelets with copper ions can reduce oxidative stress of neurons and protect neuronal cells from apoptosis. The nanoplatelet probe provides a paradigm for activatable PA imaging of brain copper levels, highlighting its potential for pathophysiologic study of AD.


Assuntos
Doença de Alzheimer , Técnicas Fotoacústicas , Animais , Camundongos , Cobre , Doença de Alzheimer/diagnóstico por imagem , Técnicas Fotoacústicas/métodos , Compostos de Zinco
8.
Nutrients ; 14(19)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36235778

RESUMO

Helicobacter pylori (H. pylori) is the most prevalent etiology of gastritis worldwide. H. pylori management depends mainly on antibiotics, especially the triple therapy formed of clarithromycin, amoxicillin, and proton pump inhibitors. Lately, many antibiotic-resistant strains have emerged, leading to a decrease in the eradication rates of H. pylori. Polaprezinc (PZN), a mucosal protective zinc-L-carnosine complex, may be a non-antibiotic agent to treat H. pylori without the risk of resistance. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of a PZN-based regimen for the eradication of H. pylori. This study used a systematic review and meta-analysis synthesizing randomized controlled trials (RCTs) from WOS, SCOPUS, EMBASE, PubMed, and Google Scholar until 25 July 2022. We used the odds ratio (OR) for dichotomous outcomes presented with the corresponding 95% confidence interval (CI). We registered our protocol in PROSPERO with ID: CRD42022349231. We included 3 trials with a total of 396 participants who were randomized to either PZN plus triple therapy (n = 199) or triple therapy alone (control) (n = 197). Pooled OR found a statistical difference favoring the PZN arm in the intention to treat and per protocol H. pylori eradication rates (OR: 2.01 with 95% CI [1.27, 3.21], p = 0.003) and (OR: 2.65 with 95% CI [1.55, 4.54], p = 0.0004), respectively. We found no statistical difference between the two groups regarding the total adverse events (OR: 1.06 with 95% CI [0.55, 2.06], p = 0.85). PZN, when added to the triple therapy, yielded a better effect concerning the eradication rates of H. pylori with no difference in adverse event rates, and thus can be considered a valuable adjuvant for the management of H. pylori. However, the evidence is still scarce, and larger trials are needed to confirm or refute our findings.


Assuntos
Carnosina , Infecções por Helicobacter , Compostos Organometálicos , Compostos de Zinco , Amoxicilina/uso terapêutico , Antibacterianos/uso terapêutico , Carnosina/análogos & derivados , Carnosina/uso terapêutico , Claritromicina/uso terapêutico , Quimioterapia Combinada , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Humanos , Compostos Organometálicos/uso terapêutico , Inibidores da Bomba de Prótons/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Compostos de Zinco/uso terapêutico
9.
Anal Bioanal Chem ; 414(29-30): 8277-8287, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36239752

RESUMO

The first, novel solid-state membrane sensor for Zn(II) determination is developed based on ZnS nanoparticles. ZnS nanoparticles are synthesized by chemical co-precipitation and investigated via X-ray diffraction, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and impedance study. X-ray diffraction shows that the prepared ZnS nanoparticles have an average domain size of 5.72 nm, which is very close to the particle size obtained from TEM observations (6.30 nm). The ZnS nanoparticles are pressed into disks and examined as electroactive solid-state membrane. Solid-state membrane and coated wire sensors are fabricated. They display linear responses over concentration ranges of 1.0 × 10-5 to 1.0 × 10-1 mol L-1 Zn2+ ions with cationic slopes of 28.9±0.2 and 25.9±0.2 mV decade-1 for the solid-state membrane and coated wire sensors, respectively. The lower limits of detection are 2.86 × 10-6 and 4.60 × 10-6 mol L-1 Zn2+ ions for the solid-state membrane and coated wire sensors, respectively. The response time for the two sensors is instantaneous (1 s), and the useful lifetimes for the solid-state membrane and coated wire sensors are long (10 and 6 months, respectively). The solid-state membrane sensor is utilized for the quantification of Zn(II) ions in brass alloys and pharmaceutical preparations.


Assuntos
Nanopartículas , Compostos de Zinco , Compostos de Zinco/química , Sulfetos/química , Nanopartículas/química , Zinco
10.
Anal Chem ; 94(43): 15067-15075, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36268852

RESUMO

Switchable theranostics are of great interest for accurate tumor imaging and targeted therapy. Here, we develop smart engineering to construct nanostructured phthalocyanines self-assembled by amphiphilic zinc phthalocyanines (ZnPcs) and hydrophobic copper phthalocyanines (CuPcs) (ZnPc(PEG)5:CuPc-N, where ZnPc(PEG)5 is monosubstituted ZnPcs with pentaethylene glycol as the substituent). The fluorescence and reactive oxygen species generation of ZnPc(PEG)5:CuPc-N can be triggered depending on the membrane of the tumor cells for the imaging and photoactivities. Concerning the stability in blood circulation, the surface of the nanocomplex is coated with polydopamine, which responds to the tumor acidic microenvironment. ZnPc(PEG)5 and CuPc focus on photodynamic and photothermal properties, respectively, and can be stimulated by a single laser beam, endowing ZnPc(PEG)5:CuPc-N a combined antitumor effect from evaluations both in vitro and in vivo. In our study, the mechanism of switchable theranostics, the strategy of combined photodynamic and photothermal therapy, and the smart nanoengineering technology of phthalocyanines with poor water solubility can be applied to other phthalocyanines or phthalocyanine-like phototherapy agents.


Assuntos
Neoplasias , Compostos Organometálicos , Fotoquimioterapia , Humanos , Fotoquimioterapia/métodos , Fluorescência , Compostos Organometálicos/química , Fototerapia , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Compostos de Zinco , Fármacos Fotossensibilizantes/uso terapêutico , Fármacos Fotossensibilizantes/química , Linhagem Celular Tumoral , Microambiente Tumoral
11.
Molecules ; 27(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36234969

RESUMO

Phosphate chemical conversion (PCC) technology has attracted extensive attention for its ability to regulate the surface properties of biomedical metals. However, titanium (Ti)-based alloys exhibit inertia because of the native passive layer, whereas zinc (Zn)-based alloys show high activity in acidic PCC solutions. The substrate performance affects the chemical reaction in the phosphating solution, which further leads to diversity in coating properties. In this work, the zinc-phosphate (ZnP) coatings are prepared on Ti alloy (TA) and Zn alloy (ZA) substrates using the PCC method, respectively. The coatings prepared herein are detected by a scanning electron microscope (SEM), X-ray diffractometer (XRD), laser scanning confocal microscope (LSCM), universal testing machine, contact angle goniometer, and electrochemical workstation system. The results show that the substrate performance has little effect on the phase composition but can significantly affect the crystal microstructure, thickness, and bonding strength of the coatings. In addition, the ZnP coatings improve the surface roughness of the substrates and show good hydrophilicity and electrochemical corrosion resistance. The formation mechanism of the ZnP coating is revealed using potential-time curves, indicating that the metal-solution interfacial reaction plays a dominant role in the deposition process.


Assuntos
Ligas , Titânio , Ligas/química , Materiais Revestidos Biocompatíveis , Corrosão , Metais , Compostos Organometálicos , Fosfatos/química , Piridinas , Propriedades de Superfície , Zinco/química , Compostos de Zinco
12.
Environ Monit Assess ; 194(12): 890, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36241946

RESUMO

A sensitive, selective, and simple spectrofluorimetric method for the detection and determination of cypermethrin (CYP) in various samples based on thioglycolic acid-caped Mn-doped ZnS quantum dots (TGA@Mn-ZnS-QDs) is reported. These quantum dots were synthesized using the Gonzalez method. The synthesized quantum dots were structurally characterized with the help of different spectroscopic techniques including X-ray diffraction (XRD) and energy dispersive X-ray (EDX) techniques and fluorescence spectroscopy. The quantum dots were used for spectrofluorimetric detection and determination of CYP. The emission peak of these quantum dots at 632 nm showed a linear quenching with increasing the concentration of CYP, noticing an excellent linear relationship between F°/F values and CYP in the range of 0.5-12 µg mL-1 with a correlation coefficient (R2) of 0.992. The influence of different physiochemical parameters such as time, pH, the concentration of quantum dots, and other pesticides interference on the fluorescence quenching was investigated. The detection limit was calculated to be 0.132 µg mL-1. The developed method was successfully applied for the detection and determination of CYP in various spiked samples (tomato, okra, pea, spinach, soil, and water) using the spike and recovery methods. The percent recoveries of CYP from these samples were found to be 77 ± 0.05% to 95 ± 0.12% at various levels.


Assuntos
Monitoramento Ambiental , Praguicidas , Piretrinas , Solo , Espectrometria de Fluorescência/métodos , Sulfetos/análise , Água/química , Compostos de Zinco
13.
CNS Drugs ; 36(10): 1079-1111, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36194365

RESUMO

The developmental and epileptic encephalopathies encompass a group of rare syndromes characterised by severe drug-resistant epilepsy with onset in childhood and significant neurodevelopmental comorbidities. The latter include intellectual disability, developmental delay, behavioural problems including attention-deficit hyperactivity disorder and autism spectrum disorder, psychiatric problems including anxiety and depression, speech impairment and sleep problems. Classical examples of developmental and epileptic encephalopathies include Dravet syndrome, Lennox-Gastaut syndrome and tuberous sclerosis complex. The mainstay of treatment is with multiple anti-seizure medications (ASMs); however, the ASMs themselves can be associated with psychobehavioural adverse events, and effects (negative or positive) on cognition and sleep. We have performed a targeted literature review of ASMs commonly used in the treatment of developmental and epileptic encephalopathies to discuss the latest evidence on their effects on behaviour, mood, cognition, sedation and sleep. The ASMs include valproate (VPA), clobazam, topiramate (TPM), cannabidiol (CBD), fenfluramine (FFA), levetiracetam (LEV), brivaracetam (BRV), zonisamide (ZNS), perampanel (PER), ethosuximide, stiripentol, lamotrigine (LTG), rufinamide, vigabatrin, lacosamide (LCM) and everolimus. Bromide, felbamate and other sodium channel ASMs are discussed briefly. Overall, the current evidence suggest that LEV, PER and to a lesser extent BRV are associated with psychobehavioural adverse events including aggressiveness and irritability; TPM and to a lesser extent ZNS are associated with language impairment and cognitive dulling/memory problems. Patients with a history of behavioural and psychiatric comorbidities may be more at risk of developing psychobehavioural adverse events. Topiramate and ZNS may be associated with negative effects in some aspects of cognition; CBD, FFA, LEV, BRV and LTG may have some positive effects, while the remaining ASMs do not appear to have a detrimental effect. All the ASMs are associated with sedation to a certain extent, which is pronounced during uptitration. Cannabidiol, PER and pregabalin may be associated with improvements in sleep, LTG is associated with insomnia, while VPA, TPM, LEV, ZNS and LCM do not appear to have detrimental effects. There was variability in the extent of evidence for each ASM: for many first-generation and some second-generation ASMs, there is scant documented evidence; however, their extensive use suggests favourable tolerability and safety (e.g. VPA); second-generation and some third-generation ASMs tend to have the most robust evidence documented over several years of use (TPM, LEV, PER, ZNS, BRV), while evidence is still being generated for newer ASMs such as CBD and FFA. Finally, we discuss how a variety of factors can affect mood, behaviour and cognition, and untangling the associations between the effects of the underlying syndrome and those of the ASMs can be challenging. In particular, there is enormous heterogeneity in cognitive, behavioural and developmental impairments that is complex and can change naturally over time; there is a lack of standardised instruments for evaluating these outcomes in developmental and epileptic encephalopathies, with a reliance on subjective evaluations by proxy (caregivers); and treatment regimes are complex involving multiple ASMs as well as other drugs.


Assuntos
Transtorno do Espectro Autista , Canabidiol , Espasmos Infantis , Brometos , Clobazam , Cognição , Etossuximida , Everolimo , Felbamato , Fenfluramina , Humanos , Lacosamida , Lamotrigina , Levetiracetam , Pregabalina , Sulfetos , Topiramato , Ácido Valproico , Vigabatrina , Compostos de Zinco , Zonisamida
14.
Angew Chem Int Ed Engl ; 61(49): e202213065, 2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36250269

RESUMO

Colloidal quantum dots (QDs) can photocatalyze diverse organic reactions. However, reported QD-photocatalysts often contain highly-toxic elements Cd or Pb, and have not surpassed prototypical transition-metal complexes in terms of their photoredox power or excited-state energy. Here we report low-toxicity ZnSe/ZnS core/shell QDs as potent visible photocatalysts to drive challenging organic transformations. To overcome the limitation of short excited-state lifetime of the QDs, we functionalize their surfaces with benzophenone ligands which can rapidly extract electrons from photoexcited QDs and sustain long-lived charge-separated states. The benzophenone anions function as potent electron relay to drive dehalogenation of aryl chlorides and additive-free polymerization of acrylates. Alternatively, the QDs are functionalized with biphenyl ligands to store energy in long-lived, energetic triplets, enabling [2+2] homo-cycloaddition of styrene and cycloaddition of carbonyls with alkenes.


Assuntos
Pontos Quânticos , Pontos Quânticos/toxicidade , Compostos de Zinco , Sulfetos , Benzofenonas
15.
Small ; 18(40): e2203093, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36069261

RESUMO

The lack of anionic carboxylate ligands on the surface of InP/ZnSe/ZnS quantum dots (QDs), where zinc carboxylate ligands can be converted to carboxylic acid or carboxylate ligands via proton transfer by 1-octanethiol, is demonstrated. The as-synthesized QDs initially have an under-coordinated vacancy surface, which is passivated by solvent ligands such as ethanol and acetone. Upon exposure of 1-octanethiol to the QD surface, 1-octanethiol effectively induces the surface binding of anionic carboxylate ligands (derived from zinc carboxylate ligands) by proton transfer, which consequently exchanges ethanol and acetone ligands that bind on the incomplete QD surface. These systematic chemical analyses, such as thermogravimetric analysis-mass spectrometry and proton nuclear magnetic resonance spectroscopy, directly show the interplay of surface ligands, and it associates with QD light-emitting diodes (QD-LEDs). It is believed that this better understanding can lead to industrially feasible QD-LEDs.


Assuntos
Pontos Quânticos , Acetona , Ácidos Carboxílicos , Etanol , Ligantes , Prótons , Pontos Quânticos/química , Solventes , Compostos de Sulfidrila , Sulfetos , Zinco , Compostos de Zinco
16.
Anal Methods ; 14(39): 3881-3889, 2022 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-36156613

RESUMO

In this study, a mesoporous silica fluorescence probe co-doped with manganese-doped zinc sulfide quantum dots (Mn:ZnS QDs) and rhodamine B (RB) and coated with molecularly imprinted polymer (MIP) has been prepared by sol-gel methods. The morphology and structure were characterized in detail by transmission electron microscopy (TEM), Fourier transform-infrared absorption spectroscopy (FT-IR) and ultraviolet-visible absorption spectroscopy (UV-vis). The probe exhibited two characteristic emission peaks at 411 nm and 582 nm, and the synchronous ratiometric fluorescence responses F411/F582 to different concentrations of 4-nitrophenol (4-NP) showed a good linear correlation in the range of 0.01-10 µmol L-1 besides achieving the sensitive detection of 4-NP with a detection limit as low as 3.0 nmol L-1 (3σ). The probe possesses the advantages of selectivity toward the target molecular structure, self-stability in the detection time domain and anti-interference ability, exhibiting excellent potential for application in 4-NP detection in different water environments.


Assuntos
Impressão Molecular , Manganês/química , Compostos de Manganês , Impressão Molecular/métodos , Polímeros Molecularmente Impressos , Nitrofenóis , Polímeros/química , Rodaminas , Dióxido de Silício/química , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos , Água , Compostos de Zinco
17.
Chemosphere ; 308(Pt 2): 136375, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36088970

RESUMO

In this work, the fabrication of the CuO on ZnCdS as a heterojunction nanocomposites were conducted by hydrothermal method and the synthesis method was confirmed by the XRD, XPS, EDS, UV-vis spectrum analysis. The CuO/ZnCdS was used as a photocathode in the bio-photoelectrochemical system (BPES) for tetracycline (TC) degradation under solar irradiation. The CuO/ZnCdS photocathode indicated substantial photocatalytic efficiency for TC degradation, due to the fast separation and transfer of photogenerated carriers. The ESR test evaluates the mechanism of degradation, and shows that ·OH, and ·O2- were contributed to TC degradation. The TC degradation was 1.59 times higher than the unilluminated process (98.72% vs 61.71). The photocatalysis test shows that the TC was degraded about 90.5% in 1.5 h. Then, the synthesized CuO/ZnCdS nanocomposites were studied for the biological application such as antifungal activities. CuO/ZnCdS nanocomposites depicted substantial antimicrobial activity versus Candida-albicans by in vitro process. Therefore, this study suggests the novel system for the antibiotics degradation, and as antifungal application.


Assuntos
Microbiota , Nanocompostos , Óxido de Zinco , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Cádmio , Compostos de Cádmio , Catálise , Cobre/farmacologia , Óxidos , Sulfetos , Tetraciclina , Zinco , Compostos de Zinco
18.
Int J Mol Sci ; 23(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36142888

RESUMO

Quantum dots (QDs) have outstanding optical properties such as strong fluorescence, excellent photostability, broad absorption spectra, and narrow emission bands, which make them useful for bioimaging. However, cadmium (Cd)-based QDs, which have been widely studied, have potential toxicity problems. Cd-free QDs have also been studied, but their weak photoluminescence (PL) intensity makes their practical use in bioimaging challenging. In this study, Cd-free QD nanoprobes for bioimaging were fabricated by densely embedding multiple indium phosphide/zinc sulfide (InP/ZnS) QDs onto silica templates and coating them with a silica shell. The fabricated silica-coated InP/ZnS QD-embedded silica nanoparticles (SiO2@InP QDs@SiO2 NPs) exhibited hydrophilic properties because of the surface silica shell. The quantum yield (QY), maximum emission peak wavelength, and full-width half-maximum (FWHM) of the final fabricated SiO2@InP QDs@SiO2 NPs were 6.61%, 527.01 nm, and 44.62 nm, respectively. Moreover, the brightness of the particles could be easily controlled by adjusting the amount of InP/ZnS QDs in the SiO2@InP QDs@SiO2 NPs. When SiO2@InP QDs@SiO2 NPs were administered to tumor syngeneic mice, the fluorescence signal was prominently detected in the tumor because of the preferential distribution of the SiO2@InP QDs@SiO2 NPs, demonstrating their applicability in bioimaging with NPs. Thus, SiO2@InP QDs@SiO2 NPs have the potential to successfully replace Cd-based QDs as highly bright and biocompatible fluorescent nanoprobes.


Assuntos
Nanopartículas , Neoplasias , Pontos Quânticos , Animais , Cádmio , Índio , Camundongos , Fosfinas , Dióxido de Silício , Sulfetos , Compostos de Zinco
19.
Anal Bioanal Chem ; 414(24): 7001-7002, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36117197
20.
Chemosphere ; 308(Pt 1): 136238, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36064017

RESUMO

Oxygen vacancies and its associated defect states have a great influence on the electronic and structural aspects of semiconductor photocatalysts, yet there is paucity of investigations about the influence of the defect states on their photocatalytic properties. Herein, this study reports the hierarchical fabrication of oxygen vacancy enriched ZnO/ZnMn2O4/ZnS-PVA nanocomposite (NCs) for the enhanced photodegradation of rifampicin and co-trimoxazole. The formation of lattice expansion induced oxygen vacancies and its associated Urbach tail energy, and n-p-n heterojunction-based S-scheme charge transfer path synergistically contributed to the boosted photocatalytic performance of the as prepared NCs. The photocatalytic performance of the nanomaterial towards rifampicin and co-trimoxazole has been determined to be 80% and 90% under visible light irradiation, respectively. Furthermore, various operating parameters including the concentration of NCs and drug, pH and interference of various ions have been evaluated. The degraded product intermediates have been elucidated by GC-MS analysis. The toxicity of the as-prepared nanomaterials has been evaluated by treating the samples with root tips of Allium cepa, where the NCs was found to be non-toxic. The study provides a new-fangled insight on the preparation and fabrication of non-toxic and defect rich nanomaterials which may help stimulate this area of research.


Assuntos
Óxido de Zinco , Cebolas , Oxigênio , Fotólise , Rifampina , Sulfetos , Combinação Trimetoprima e Sulfametoxazol , Compostos de Zinco , Óxido de Zinco/química , Óxido de Zinco/toxicidade
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