RESUMEN

The development of innovative multi-emission sensors for the rapid and accurate detection of contaminants is both vital and challenging. In this study, utilizing two rigid ligands (H3ICA and H4BTEC), a series of water-stable bimetallic organic frameworks (EuTb-MOFs) were synthesized. Luminescent investigations have revealed that EuTb-MOF-1 exhibits prominent multiple emission peaks, attributed to the distinctive fluorescence characteristics of Eu(III) and Tb(III) ions. Therefore, EuTb-MOF-1 efficiently recognized various metal ions and pharmaceutical compounds through 2D decoded maps. Fe3+ and Pb2+ exhibited significant quenching effects on the luminescence of EuTb-MOF-1, which were attributed to the internal filtering effect and the interaction between Lewis basic sites within EuTb-MOF-1 and Pb2+ ions, respectively. Furthermore, EuTb-MOF-1 demonstrated high sensitivity to sulfonamide antibiotics, with detection limits of 0.037 µM for SMZ and 0.041 µM for SDZ, respectively. In addition, EuTb-MOF-1 was immobilized to prepare MOF-based test strips, enabling direct visual detection of sulfonamides as a portable sensor. With excellent water stability, multi-responsive recognition capabilities, and high sensitivity to specific analytes, EuTb-MOF-1 is a promising candidate for environmental contaminant detection in aquatic systems.

Asunto(s)

RESUMEN

The present work explores the specificity of supramolecular assemblies comprising dialkylaminostyrylhetarene dye molecules incorporated into phosphatidylcholine (PC) or phosphatidylserine (PS) aggregates. In PS-based assemblies, the dyes demonstrate a concentration-dependent fluorescent response, distinguishing anionic proteins such as bovine serum albumin (BSA) and pepsin from lysozyme (LYZ) in aqueous solutions. Conversely, no significant response is observed when the dyes are incorporated into the well-organized bilayers of neutral PC. The fluorescent response arises from the binding of dyes to proteins, leading to the detachment of dye molecules from the assemblies, rather than from the binding of proteins to the assemblies, although the latter process is facilitated by electrostatic attraction. Thus, both the poor ordering of PS molecules and the interfacial arrangement of the dyes are prerequisites for the fluorescent response of dye-PS aggregates. The structure of the dyes significantly impacts the spectral features of dye-PS and dye-protein assemblies. An optimal dye structure has been identified for the recognition of BSA, with a limit of detection (LOD) of 10.8 nM.

Asunto(s)

RESUMEN

Today, diabetes mellitus is one of the most common diseases that affects the population on a worldwide scale. Patients suffering from this disease are required to control their blood-glucose levels several times a day through invasive methods such as piercing their fingers. Our NaGdF4: 5% Er3+, 3% Nd3+ nanoparticles demonstrate a remarkable ability to detect D-glucose levels by analysing alterations in their red-to-green ratio, since this sensitivity arises from the interaction between the nanoparticles and the OH groups present in the D-glucose molecules, resulting in discernible changes in the emission of the green and red bands. These luminescent sensors were implemented and tested on paper substrates, offering a portable, low-cost and enzyme-free solution for D-glucose detection in aqueous solutions with a limit of detection of 22 mg/dL. With this, our study contributes to the development of non-invasive D-glucose sensors, holding promising implications for managing diabetes and improving overall patient well-being with possible future applications in D-glucose sensing through tear fluid.

Asunto(s)

RESUMEN

The detection of antibiotics and pesticides are of great significance since their residues threaten the health of human beings by accumulation. However, most traditional solid chemical sensors are suffer from the limitations of low sensitivity and economic practicability because of the aggregating nature and unstable of solid sensors. Herein, a new luminescent sensor 1@PMMA (1, [(ZnL)·H2O]n (H2L = 5-(4-(pyridin-4-yl)benzamido)benzene-1,3-dioic acid); PMMA = poly(methyl methacrylate)) was successfully prepared. Notably, the polymer matrix provided the chemical protection for MOF particles. The as fabricated 1@PMMA was stable in milk, honey and egg as well as exhibited strong blue emission under ultraviolet light irradiation, which can act as luminescent probe for detecting antibiotics and pesticides. More interestingly, 1@PMMA exhibited visual, real-time and recyclable detection of antibiotics ornidazole (ODZ) and pesticides 2,6-dichloro-4-nitrobenzenamine (DCN) in real food samples. This work shows that the luminescent MOF-based mixed matrix membranes could be applied as good candidates for sensing analytes in practical application.

Asunto(s)

RESUMEN

The rapid detection of epinephrine (EPI) in serum holds immense importance in the early disease diagnosis and regular monitoring. On the basis of the coordination post-synthetic modification (PSM) strategy, a Eu3+ functionalized ZnMOF (Eu3+@ZnMOF) was fabricated by anchoring the Eu3+ ions within the microchannels of ZnMOF as secondary luminescent centers. Benefiting from two independent luminescent centers, the prepared Eu3+@ZnMOF shows great potential as a multi-signal self-calibrating luminescent sensor in visually and efficiently detecting serum EPI levels, with high reliability, fast response time, excellentrecycleability, and low detection limits of 17.8 ng/mL. Additionally, an intelligent sensing system was designed in accurately and reliably detecting serum EPI levels, based on the designed self-calibrating logic gates. Furthermore, the possible sensing mechanisms were elucidated through theoretical calculations as well as spectral overlaps. This work provides an effective and promising strategy for developing MOFs-based self-calibrating intelligent sensing platforms to detect bioactive molecules in bodily fluids.

Asunto(s)

RESUMEN

A new 3D metal-organic framework {[Cd16(tr2btd)10(dcdps)16(H2O)3(EtOH)]∙15DMF}n (MOF 1, tr2btd = 4,7-di(1,2,4-triazol-1-yl)benzo-2,1,3-thiadiazole, H2dcdps = 4,4'-sulfonyldibenzoic acid) was obtained and its luminescent properties were studied. MOF 1 exhibited bright blue-green luminescence with a high quantum yield of 74 % and luminescence quenching response to a toxic natural polyphenol gossypol and luminescence enhancement response to some trivalent metal cations (Fe3+, Cr3+, Al3+ and Ga3+). The limit of gossypol detection was 0.20 µM and the determination was not interfered by the components of the cottonseed oil. The limit of detection of gallium(III) was 1.1 µM. It was demonstrated that MOF 1 may be used for distinguishing between the genuine sunflower oil and oil adulterated by crude cottonseed oil through qualitative luminescent and quantitative visual gossypol determination.

Asunto(s)

RESUMEN

BACKGROUD: Single oxygen (1O2), the molecular oxygen at its excited state, plays a crucial role in the photodynamic therapy (PDT) of some diseases owing to its strong oxidizing property to destroy malignant cells. Although the fluorescent probe technique has proven its powerful application abilities for detection of 1O2 in biological systems, most of the reported fluorescent probes suffered from the interference of background autofluorescence of biological samples. It is clear that the real-time and in situ, background-free fluorescent detection of 1O2 generated in live cells, especially in some organelles, is of great significance for understanding the action mechanism of PDT drugs. RESULTS: By introducing a lysosome-anchoring motif, a morpholine moiety, into a 1O2-specifically-reactive terpyridine polyacid ligand, [4'-(9-anthryl)-2,2':6',2″-terpyridine-6,6″-diyl] bis(methylenenitrilo) tetrakis (acetic acid) (ATTA), and chelating with lanthanide ions (Eu3+ or Tb3+), two lanthanide complex-based "turn-on" luminescent probes that can be used for the background-free time-gated luminescent (TGL) detection of lysosomal 1O2, Lyso-ATTA-Eu3+ and Lyso-ATTA-Tb3+, have been developed. The probes exhibit fast luminescence responses (within 2.5 min) towards 1O2 with high selectivity and sensitivity (<0.75 µM) in a wide pH range (4-11). And the excellent lysosome-localization performance of the probes allowed them to be used for the monitoring of endogenous 1O2 in lysosomes, which enabled the variability of lysosomal-1O2 concentrations induced by different photosensitizers to be successfully discriminated. Furthermore, by doping Lyso-ATTA-Eu3+ into the polyethylene glycol (PEG) hydrogel, the smart luminescent sensor film, PEG-Lyso-ATTA-Eu3+, was prepared, and successfully used for the detection of the on-site 1O2 production during the PDT process of psoriatic disease in model mice. SIGNIFICANT: Two lysosome-targetable background-free TGL probes for 1O2 were firstly reported. The developed smart luminescent sensor film could be a powerful tool for the clinical monitoring of PDT on skin diseases without using sophisticated and expensive instruments.

Asunto(s)

RESUMEN

The rapid and accurate sensing of p-xylene, an essential raw material with a multi-billion-dollar market, in xylene mixture is of great significance in industry; however, the highly similar molecular structures, energy levels, and spectral characteristics of xylene isomers make the selective recognition extremely challenging. Metal-organic frameworks (MOFs) exhibiting tailorable pores and potential binding sites provide prospects for xylene sensing but a comprehensive understanding of the pore effect is still elusive, primarily due to the intricacies involved in the sensing process. Herein, we reported a robust bilanthanide MOF NKU-999-EuTb with precisely engineered pores to accommodate p-xylene, of which the binding sites were confirmed by single crystal X-ray diffraction and dynamic magnetic susceptibilities. NKU-999-EuTb exhibits high-performance in selective recognition for p-xylene towards its isomers. Through a systematical study, it was revealed that absorbing p-xylene into the pores governs the sensing performance. This work provides insights for developing advanced sensing materials for complex isomers.

RESUMEN

A new Ni coordination polymer [Ni(MIP)(BMIOPE)]n (1) was constructed (BMIOPE = 4,4'-bis(2-methylimidazol-1-yl)diphenyl ether, and H2MIP = 5-methylisophthalic acid), possessing two-dimensional (2D) twofold parallel interwoven net structure with a 44∙62 point symbol. Complex 1 has been successfully obtained based on mixed-ligand strategy. The fluorescence titration experiments revealed that complex 1 could act as multifunctional luminescent sensor to simultaneously detect UO22+, Cr2O72- and CrO42-, and NFT (nitrofurantoin). The limit of detection (LOD) values for complex 1 are 2.86 × 10-5, 4.09 × 10-5, 3.79 × 10-5 and 9.32 × 10-5 M for UO22+, Cr2O72-, CrO42- and NFT. The Ksv values are 6.18 × 103, 1.44 × 104, 1.27 × 104 and 1.51 × 104 M-1 for NFT, CrO42-, Cr2O72- and UO22+. Finally, the mechanism of its luminescence sensing is studied in detail. These results manifest that complex 1 is a multifunctional sensor for sensitive fluorescent UO22+, Cr2O72-, CrO42- and NFT detection.

RESUMEN

Increasing trace levels of antibiotics and hormones in the environment and food samples are concerning and pose a threat. Opto-electrochemical sensors have received attention due to their low cost, portability, sensitivity, analytical performance, and ease of deployment in the field as compared to conventional expensive technologies that are time-consuming and require experienced professionals. Metal-organic frameworks (MOFs) with variable porosity, active functional sites, and fluorescence capacity are attractive materials for developing opto-electrochemical sensors. Herein, the insights into the capabilities of electrochemical and luminescent MOF sensors for detection and monitoring of antibiotics and hormones from various samples are critically reviewed. The detailed sensing mechanisms and detection limits of MOF sensors are addressed. The challenges, recent advances, and future directions for the development of stable, high-performance MOFs as commercially viable next-generation opto-electrochemical sensor materials for the detection and monitoring of diverse analytes are discussed.

RESUMEN

The present work demonstrates the optimization of the ligand structure in the series of bis(phosphine oxide) and ß-ketophosphine oxide representatives for efficient coordination of Tb3+ and Eu3+ ions with the formation of the complexes exhibiting high Tb3+- and Eu3+-centered luminescence. The analysis of the stoichiometry and structure of the lanthanide complexes obtained using the XRD method reveals the great impact of the bridging group nature between two phosphine oxide moieties on the coordination mode of the ligands with Tb3+ and Eu3+ ions. The bridging imido-group facilitates the deprotonation of the imido- bis(phosphine oxide) ligand followed by the formation of tris-complexes. The spectral and PXRD analysis of the separated colloids indicates that the high stability of the tris-complexes provides their safe conversion into polystyrenesulfonate-stabilized colloids using the solvent exchange method. The red Eu3+-centered luminescence of the tris-complex exhibits the same specificity in the solutions and the colloids. The pronounced luminescent response on the antibiotic ceftriaxone allows for sensing the latter in aqueous solutions with an LOD value equal to 0.974 µM.

RESUMEN

As hazardous environmental pollutants, residual tetracycline (TC) and acetone are harmful to the ecosystem. Therefore, it is necessary to detect the presence of these pollutants in the environment. In this work, using Zn (II) salt, 4-(4-carboxy phenoxy) phthalic acid (H3L), and 3,5-bis(1-imidazolyl) pyridine (BMP), a new metal-organic framework (Zn-MOF) known as [Zn3(BMP)2L2(H2O)4]·2H2O was synthesized using a one-pot hydrothermal method. The Zn-MOF has a three-dimensional framework based on the [Zn1N2O2] and [Zn2N2O4] nodes linked by a tridentate bridge BMP ligand and an L ligand with the µ1:η1η0/µ1:η1η0/µ0:η0η0 coordination mode. There were two kinds of left- and right-handed helix chains, Zn1-BMP and Zn1-BMP-Zn1-L. The complex was stable in aqueous solutions with pH values of 4-10. The Zn-MOF exhibited a strong emission band centered at 385 nm owing to the π*→π electron transition of the ligand. It showed high luminescence in some common organic solvents as well as in the aqueous solutions of pH 4-10. Interestingly, TC and acetone effectively quenched the luminescence of the Zn-MOF in aqueous solution and enabled the Zn-MOF to be used as a sensor to detect TC and acetone. The detection limits of TC and acetone were observed to be 3.34 µM and 0.1597%, respectively. Even in acidic (pH = 4) and alkaline (pH = 10) conditions, the Zn-MOF showed a stable luminescence sensing capability to detect TC. Luminescence sensing of the Zn-MOF for TC in urine and aquaculture wastewater systems was not affected by the interfering agent. Furthermore, the mechanism of sensing TC was investigated in this study. Fluorescence resonance energy transfer and photoinduced electron transfer were found to be the possible quenching mechanisms via UV-Vis absorption spectra/the excitation spectra measurements and DFT calculations.

RESUMEN

Countless people have been affected by the COVID-19 pandemic on a global scale. Favipiravir, has shown potential as an effective drug for SARS-CoV-2, attracting scientists' attention. However, overuse of Favipiravir easily leads to serious side effects, requiring real-time monitoring in body fluids. Given this, a new lanthanide metal-organic framework (MOF) was prepared under solvothermal conditions from either Eu (Eu-MOF or (1)) or Tb (Tb-MOF or (2)) using the highly delocalized imidazoledicarboxylic acid linker H2 L (H2 L=5-(4-(imidazol-1-yl) phenyl) isophthalic acid) and could be successfully applied to selective optical detection of Favipiravir. In this MOF framework, the organic linker H2 L provides a high excitation energy transfer efficiency that can sensitize luminescence in lanthanides. In addition, through deliberate tuning of Eu/Tb molar ratio and reaction concentration in the lanthanide framework, ratiometric recyclable luminescent Eux Tb1-x -MOF nanoparticles with open metal sites have been constructed, which present a high detection sensitivity (Ksv =1×107 [M-1 ], detection limit is 4.63 nM) for Favipiravir. The detection mechanism is discussed with the help of Density Functional Theory (DFT) calculations that sheds light over the selective sensing of Favipiravir over other related COVID-19 drug candidates. Finally, to explore the practical application of Favipiravir sensing, MOF based thin films have been used for visual detection of Favipiravir and recycled 5 times.

Asunto(s)

RESUMEN

Luminescent aerogels based on sodium alginate cross-linked with ions of rare earth elements (Eu3+, Tb3+, Sm3+) and containing phenanthroline, thenoyltrifluoroacetone, dibenzoylmethane, and acetylacetone as ligands introduced into the matrix during the impregnation of alginate aerogels (AEG), were obtained for the first time in a supercritical carbon dioxide medium. The impregnation method used made it possible to introduce organically soluble sensitizing ligands into polysaccharide matrices over the entire thickness of the sample while maintaining the porous structure of the aerogel. It is shown that the pore size and their specific area are 150 nm and 270 m2/g, respectively. Moreover, metal ions with content of about 23 wt.%, acting as cross-linking agents, are uniformly distributed over the thickness of the sample. In addition, the effect of sensitizing ligands on the luminescence intensity of cross-linked aerogel matrices is considered. The interaction in the resulting metal/ligand systems is unique for each pair, which is confirmed by the detection of broad bands with individual positions in the luminescence excitation spectra of photoactive aerogels.

RESUMEN

Hydrogen-bonded organic frameworks (HOFs), as a newly developed porous material, have been widely used in various fields. To date, several organic building units (OBUs) with tri-, tetra-, and hexa-carboxylic acid synthons have been applied to synthesize HOFs. To our knowledge, di-carboxylic acids have rarely been reported for the construction of HOFs, in particular, di-carboxylic acid-based HOFs with fluorescence sensing properties have not been reported. In this study, a rare example of a di-carboxylic acid-based, luminescent three-dimensional hydrogen-bonded organic framework has been successfully constructed and structurally characterized; it has a strong electron-rich property originated from its organic linker 9-phenylcarbazole-3,6-dicarboxylic acid. It represents the first example of HOF-based sensors for the highly selective and sensitive detection of PA (Picric acid) with reusability; the LOD is less than 60 nM. This work thus provides a new avenue for the fabrication of fluorescent HOFs sensing towards explosives.

Asunto(s)

RESUMEN

Porosity is a fundamental property of metal-organic frameworks (MOFs). However, the role of the pore size has always been underestimated in MOF-based luminescent sensors for enantioselective sensing. The construction of isoreticular MOFs (IRMOFs) with variable pore sizes and the synergy between chirality and luminescence is challenging. Herein, a general strategy was developed to introduce chirality into two well-known IRMOF-74 analogs with nanochannels of identical shapes but different pore sizes by functionalizing the open metal site under mild conditions. To enhance the detection accuracy, a second luminescent center was introduced into the IRMOF-74 system to achieve ratiometric sensing. The two bifunctionalized IRMOF-74 compounds exhibited pore-size-dependent sensing performance for enantiomers. This study not only provides a convenient method to construct chiral MOFs as advanced sensing materials but also reveals the fundamental of the pores in MOF-based luminescent sensors.

RESUMEN

The metal-organic framework materials have an important application as sensors. In this work, a microporous three-dimensional (3D) Eu(III)-organic framework (Eu-MOF), [Eu2(3,5-bct)(phen)2(ox)2(H2O)]·H2O, was constructed from 3,5-bis(3'-carboxyphenyl)-1,2,4-triazole (3,5-H2bct), oxalate (ox) and 1,10-phenanthroline (phen) as a luminescent sensor. The free volume was found to be 15.7% per unit volume ignoring the free water molecules. The Eu-MOF showed bright red light due to the emission at 622 nm (5D0 → 7F2 transition) of the Eu(III) with high quantum yield (QY, 52.51%). The Eu-MOF exerted high luminescence stability in common organic solvents as well as aqueous solutions within a wide pH range from 4 to 11. Based on the luminescent Eu-MOF, the sensing behavior for colchicine in the aqueous environment was studied. Highly selective and sensitive detection (LOD = 2.43 × 10-5 mol L-1) of colchicine was observed by the Eu-MOF even in the presence of potential interfering components. The sensing mechanism for colchicine was investigated by experimental and theoretical results. It is worth noting that a film (Film@Eu-MOF) prepared by loading Eu-MOF showed intense characteristic red light emission under UV light. The luminescence color changed immediately from red to colorless when the Film@Eu-MOF came in contact with colchicine. Highly sensitive and rapid detection of colchicine in wastewater was achieved using this Film@Eu-MOF, which could be identified by the naked eye. The experimental results suggest that the synthesized Eu-MOF has potential application as a luminescent sensing material for pollutants in the environmental system.

Asunto(s)

RESUMEN

The level of L-kynurenine (L-kyn) can reflect the health state of human body, and the determination of L-kyn can be used for the medical diagnosis of several cancers and neurological diseases. In this work, a series of air-, water-, and thermo-stable dinuclear lanthanide nanoclusters [Ln2(2,5-DFBA)6(phen)2] (Tb 1, Eu 2, Gd 3, 2,5-DFBA = 2,5-difluorobenzoic acid, phen = 1,10-phenanthroline) are obtained by a facial method. 1 and 2 show very high luminescence quantum yields (QYs) of 71.7% and 81.8%, respectively. Interestingly, investigation reveals that 1 is a quick, highly sensitive and selective sensor for L-kyn in real samples of urine and serum. Furthermore, transmission electron microscope (TEM) results reveal that nanocluster 1 is stable in solution and can be uniform distributed on the base, suggesting it can be deposited on various supports to fabricate sensing devices. Thus, 1 is fabricated into a sensitive test paper for the eye-readable detection of L-kyn in real samples of human urine and serum. The limit of detection (LOD) as low as 0.3 µM, which is enough to rapidly determine L-kyn in human body liquor (usually 5 µM in healthy human body).

Asunto(s)

RESUMEN

The small molecule 8-methoxy-2-oxo-1,2,4,5-tetrahydrocyclopenta[de]quinoline-3-carboxylic acid (2b) behaves as a reactive non-fluorescent Michael acceptor, which after reaction with thiols becomes fluorescent, and an efficient Eu3+ antenna, after self-assembling with this cation in water. This behavior makes 2b a highly selective GSH biosensor, which has demonstrated high potential for studies in murine and human cells of the immune system (CD4+ T, CD8+ T, and B cells) using flow cytometry. GSH can be monitored by the fluorescence of the product of addition to 2b (445 nm) or by the luminescence of Eu3+ (592 nm). 2b was able to capture baseline differences in GSH intracellular levels among murine and human CD4+ T, CD8+ T, and B cells. We also successfully used 2b to monitor intracellular changes in GSH associated with the metabolic variations governing the induction of CD4+ naïve T cells into regulatory T cells (TREG).

Asunto(s)

RESUMEN

In this study, a new Cd(II)-bearing coordination polymer with the chemical formula of {[Cd4(meda)3(dpe)4(H2O)4]·(NO3)2·2(H2O)}n (1, H2meda = 3,3'-methylenedibenzoic acid, dpe = 1,2-di(pyridin-4-yl)ethane) has been successfully prepared by reaction of Cd(NO3)·4H2O with a V-shape carboxyl ligand H2meda along with the linear dipyridine ligand dpe under the hydrothermal conditions. Due to its intensive luminescence, complex 1 could be utilized as the sensor of detecting Al3+ ion, and its detection limit is 4 × 10-6 M. Firstly, the toxicity of the compound on the normal liver cells was determined with Cell Counting Kit-8 detection kit. The triglyceride in liver cells was detected by detection kit after compound treatment and the relative expression of 15-lox and 12-lox in L02 cells was also measured by RT-PCR after compound treatment. In addition, multiple functional groups that provided by the synthesized Cd(II) complex have been studied by using molecular docking simulation for the confirmation of possible binding modes that formed between ligand and receptor.

Asunto(s)