Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Adv Sci (Weinh) ; : e2309992, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38774946

RESUMEN

Radiotherapy demonstrates a synergistic effect with immunotherapy by inducing a transformation of "immune cold" tumors into "immune hot" tumors in triple negative breast cancer (TNBC). Nevertheless, the effectiveness of immunotherapy is constrained by low expression of tumor-exposed antigens, inadequate inflammation, and insufficient tumor infiltrating lymphocyte (TILs). To address this predicament, novel lutecium-based rare earth nanoparticles (RENPs) are synthesized with the aim of amplifying radiation effect and tumor immune response. The nanoprobe is characterized by neodymium-based down-conversion fluorescence, demonstrating robust photostability, biocompatibility, and targetability. The conjugation of RENPs with a CXCR4 targeted drug enables precise delineation of breast tumors using a near-infrared imaging system and improves radiation efficacy via lutetium-based radio-sensitizer in vivo. Furthermore, the study shows a notable enhancement of immune response through the induction of immunogenic cell death and recruitment of TILs, resulting in the inhibition of tumor progression both in vitro and in vivo models following the administration of nanoparticles. Hence, the novel multifunctional nanoprobes incorporating various lanthanide elements offer the potential for imaging-guided tumor delineation, radio-sensitization, and immune activation post-radiation, thus presenting an efficient radio-immunotherapeutic approach for TNBC.

2.
Int J Nanomedicine ; 18: 5141-5157, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37705867

RESUMEN

Background: Durable responses to immune-checkpoint blocking therapy (ICT) targeting programmed cell death protein-1/ligand-1 (PD-1/PD-L1) have improved outcomes for patients with triple negative breast cancer (TNBC). Unfortunately, only 19-23% of patients benefit from ICT. Hence, non-invasive strategies evaluating responses to therapy and selecting patients who will benefit from ICT are critical issues for TNBC immunotherapy. Methods: We developed a novel nanoparticle-Atezolizumab (NPs-Ate) consisting of indocyanine green (ICG), gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), human serum albumin (HSA), and Atezolizumab. The efficiency of Gd-DTPA linking was verified using mass spectrometry, and the size of NPs-Ate was characterized using Nano-flow cytometry. The synthesized NPs-Ate were evaluated for fluorescence stability, penetration depth, and target specificity. TNBC cell lines and tumor-bearing mice models were used to identify the feasibility of this dual-modal second near-infrared/magnetic resonance imaging (NIR-II/MRI) system. Additionally, ICT combination with chemotherapy or radiotherapy in TNBC tumor-bearing mice models were used to assess dynamic changes of PD-L1 and predicted therapeutic responses with NPs-Ate. Results: Atezolizumab, a monoclonal antibody, was successfully labeled with ICG and Gd-DTPA to generate NPs-Ate. This demonstrated strong fluorescence signals in our NIR-II imaging system, and relaxivity (γ1) of 9.77 mM-1 s-1. In tumor-bearing mice, the NIR-II imaging signal background ratio (SBR) reached its peak of 11.51 at 36 hours, while the MRI imaging SBR reached its highest as 1.95 after 12 hours of tracer injection. NPs-Ate specifically targets cells and tumors expressing PD-L1, enabling monitoring of PD-L1 status during immunotherapy. Combining therapies led to inhibited tumor growth, prolonged survival, and increased PD-L1 expression, effectively monitored using the non-invasive NPs-Ate imaging system. Conclusion: The NIR-II/MRI NPs-Ate effectively reflected PD-L1 status during immunotherapy. Real-time and non-invasive immunotherapy and response/prognosis monitoring under NIR-II/MRI imaging guidance in TNBC is a promising and innovative technology with potential for extensive clinical applications in the future.


Asunto(s)
Neoplasias de la Mama Triple Negativas , Humanos , Animales , Ratones , Neoplasias de la Mama Triple Negativas/diagnóstico por imagen , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Antígeno B7-H1 , Gadolinio DTPA , Inmunoterapia , Imagen por Resonancia Magnética , Verde de Indocianina
3.
Cancer Res ; 83(20): 3428-3441, 2023 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-37540231

RESUMEN

Sentinel lymph node (SLN) biopsy plays a critical role in axillary staging of breast cancer. However, traditional SLN mapping does not accurately discern the presence or absence of metastatic disease. Detection of SLN metastasis largely hinges on examination of frozen sections or paraffin-embedded tissues post-SLN biopsy. To improve detection of SLN metastasis, we developed a second near-infrared (NIR-II) in vivo fluorescence imaging system, pairing erbium-based rare-earth nanoparticles (ErNP) with bright down-conversion fluorescence at 1,556 nm. To visualize SLNs bearing breast cancer, ErNPs were modified by balixafortide (ErNPs@POL6326), a peptide antagonist of the chemokine receptor CXCR4. The ErNPs@POL6326 probes readily drained into SLNs when delivered subcutaneously, entering metastatic breast tumor cells specifically via CXCR4-mediated endocytosis. NIR fluorescence signals increased significantly in tumor-positive versus tumor-negative SLNs, enabling accurate determination of SLN breast cancer metastasis. In a syngeneic mouse mammary tumor model and a human breast cancer xenograft model, sensitivity for SLN metastasis detection was 92.86% and 93.33%, respectively, and specificity was 96.15% and 96.08%, respectively. Of note, the probes accurately detected both macrometastases and micrometastases in SLNs. These results overall underscore the potential of ErNPs@POL6326 for real-time visualization of SLNs and in vivo screening for SLN metastasis. SIGNIFICANCE: NIR-IIb imaging of a rare-earth nanoprobe that is specifically taken up by breast cancer cells can accurately detect breast cancer macrometastases and micrometastases in sentinel lymph nodes.


Asunto(s)
Neoplasias de la Mama , Ganglio Linfático Centinela , Animales , Ratones , Humanos , Femenino , Metástasis Linfática/diagnóstico por imagen , Metástasis Linfática/patología , Ganglio Linfático Centinela/diagnóstico por imagen , Ganglio Linfático Centinela/patología , Neoplasias de la Mama/patología , Ganglios Linfáticos/diagnóstico por imagen , Ganglios Linfáticos/patología , Micrometástasis de Neoplasia/patología , Biopsia del Ganglio Linfático Centinela/métodos , Estadificación de Neoplasias , Axila/patología
4.
Adv Sci (Weinh) ; 10(10): e2205294, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36721054

RESUMEN

Breast-conserving surgery (BCS) is the predominant treatment approach for initial breast cancer. However, due to a lack of effective methods evaluating BCS margins, local recurrence caused by positive margins remains an issue. Accordingly, radiation therapy (RT) is a common modality in patients with advanced breast cancer. However, while RT also protects normal tissue and enhances tumor bed doses to improve therapeutic effects, current radiosensitizers cannot meet these urgent clinical needs. To address this, a novel self-assembled multifunctional nanoprobe (NP) gadolinium (Gd)-diethylenetriaminepentaacetic acid-human serum albumin (HSA)@indocyanine green-Bevacizumab (NPs-Bev) is synthesized to improve the efficacy of fluorescence-image-guided BCS and RT. Fluorescence image guidance of the second near infrared NP improves complete resection in tumor-bearing mice and accurately discriminates between benign and malignant mammary tissue in transgenic mice. Moreover, targeting tumors with NPs induces more reactive oxygen species under X-ray radiation therapy, which not only increases RT sensitivity, but also reduces tumor progression in mice. Interestingly, self-assembled NPs-Bev using HSA, the magnetic resonance contrast agent and Bevacizumab-targeting vascular growth factor A, which are clinically safe reagents, are safe in vitro and in vivo. Therefore, the novel self-assembled NPs provide a solid precision therapy platform to treat breast cancer.


Asunto(s)
Neoplasias de la Mama , Humanos , Ratones , Animales , Femenino , Neoplasias de la Mama/radioterapia , Neoplasias de la Mama/cirugía , Bevacizumab/uso terapéutico , Verde de Indocianina/uso terapéutico , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética
5.
Crit Rev Oncol Hematol ; 176: 103746, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35752425

RESUMEN

Recently, immune checkpoint therapy (ICT) represented by programmed cell death1 (PD-1) and its major ligands, programmed death ligand 1 (PD-L1), has achieved significant success. Detection of PD-L1 by immunohistochemistry (IHC) is a classic method to guide the treatment of ICT patients. However, PD-L1 expression in the tumor microenvironment is highly complex. Thus, PD-L1 IHC is inadequate to fully understand the relevance of PD-L1 levels in the whole body and their dynamics to improve therapeutic outcomes. Intriguingly, numerous studies have revealed that molecular imaging technologies could potentially meet this need. Therefore, the purpose of this narrative review is to summarize the preclinical and clinical application of ICT guided by molecular imaging technology, and to explore the future opportunities and practical difficulties of these innovations.


Asunto(s)
Antígeno B7-H1 , Microambiente Tumoral , Humanos , Inmunohistoquímica , Imagen Molecular , Pronóstico
6.
Inorg Chem ; 61(6): 2724-2732, 2022 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-35089029

RESUMEN

A SiO2@MOF core-shell microsphere for environmentally friendly applications was introduced in this study. Several types of metal-organic framework core-shell microspheres were successfully synthesized. To achieve high stability and favorable catalytic performance, modification and coating methods were necessary for optimization. The improved SiO2@MOF core-shell microspheres were used in the cycloaddition reaction of carbon dioxide and propylene oxide. Dispersion ability was enhanced by the addition of core-shell microspheres, which also produced high catalytic activity. Accompanied with tetrabutylammonium bromide as a co-catalyst, SiO2@ZIF-67 had a maximum conversion of 97%, and the results revealed that SiO2@ZIF-67 could be used for 5 reaction cycles while maintaining high catalytic performance. This recycling catalyst was also reacted with a series of terminal epoxides to form corresponding cyclic carbonates with high conversion rates, indicating that SiO2@MOF core-shell microspheres exhibit promise in the field of catalysis.

7.
Cell Death Dis ; 12(6): 502, 2021 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-34006834

RESUMEN

Notch receptors (Notch1-4) play critical roles in tumorigenesis and metastasis of malignant tumors, including breast cancer. Although abnormal Notch activation is related to various tumors, the importance of single receptors and their mechanism of activation in distinct breast cancer subtypes are still unclear. Previous studies by our group demonstrated that Notch3 may inhibit the emergence and progression of breast cancer. PTEN is a potent tumor suppressor, and its loss of function is sufficient to promote the occurrence and progression of tumors. Intriguingly, numerous studies have revealed that Notch1 is involved in the regulation of PTEN through its binding to CBF-1, a Notch transcription factor, and the PTEN promoter. In this study, we found that Notch3 and PTEN levels correlated with the luminal phenotype in breast cancer cell lines. Furthermore, we demonstrated that Notch3 transactivated PTEN by binding CSL-binding elements in the PTEN promoter and, at least in part, inhibiting the PTEN downstream AKT-mTOR pathway. Notably, Notch3 knockdown downregulated PTEN and promoted cell proliferation and tumorigenesis. In contrast, overexpression of the Notch3 intracellular domain upregulated PTEN and inhibited cell proliferation and tumorigenesis in vitro and in vivo. Moreover, inhibition or overexpression of PTEN partially reversed the promotion or inhibition of cell proliferation induced by Notch3 alterations. In general, Notch3 expression positively correlated with elevated expression of PTEN, ER, lower Ki-67 index, and incidence of involved node status and predicted better recurrence-free survival in breast cancer patients. Therefore, our findings demonstrate that Notch3 inhibits breast cancer proliferation and suppresses tumorigenesis by transactivating PTEN expression.


Asunto(s)
Neoplasias de la Mama/metabolismo , Fosfohidrolasa PTEN/metabolismo , Receptor Notch3/metabolismo , Animales , Neoplasias de la Mama/genética , Carcinogénesis , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Femenino , Humanos , Ratones , Ratones Desnudos , Pronóstico , Análisis de Supervivencia , Transfección
8.
Materials (Basel) ; 14(4)2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33670380

RESUMEN

This work presents an efficient and facile strategy to prepare an α-amylase bioreactor. As enzymes are quite large to be immobilized inside metal-organic frameworks (MOFs), the tertiary and quaternary structures of α-amylase were first disrupted using a combination of urea, dithiothreitol (DTT), and iodoacetamide (IAA). After losing its tertiary structure, the unfolded proteins can now penetrate into the microporous MOFs, affording fragmented α-amylase@MOF bioreactors. Among the different MOFs evaluated, UiO-66 gave the most promising potential due to the size-matching effect of the α-helix of the fragmented α-amylase with the pore size of UiO-66. The prepared bioreactor exhibited high yields of small carbohydrate (maltose) even when reused up to 15 times (>80% conversion).

9.
Dalton Trans ; 50(5): 1866-1873, 2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33470994

RESUMEN

In this paper, we describe the facile preparation of a chiral catalyst by the combination of the amino acid, l-proline (Pro), and the enzyme, porcine pancreas lipase (PPL), immobilized on a microporous metal-organic framework (PPL-Pro@MOF). The multipoint immobilization of PPL onto the MOF is made possible with the aid of Pro, which also provided a chiral environment for enhanced enantioselectivity. The application of the microporous MOF is pivotal in maintaining the catalytic activity of PPL, wherein it prevented the leaching of Pro during the catalytic reaction, leading to the enhanced activity of PPL. The prepared biocatalyst was applied in asymmetric carbon-carbon bond formation, demonstrating the potential of this simple approach for chemical transformations.


Asunto(s)
Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Lipasa/química , Lipasa/metabolismo , Estructuras Metalorgánicas/química , Prolina/química , Animales , Reactores Biológicos , Líquidos Iónicos/química , Cinética , Estereoisomerismo , Porcinos
10.
Endocrinology ; 161(10)2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32348468

RESUMEN

The incidence of papillary thyroid cancer (PTC) with concomitant Hashimoto thyroiditis (HT) is increasing. Interleukin (IL)-10 is a cytokine previously reported to be elevated in this condition. Evidence from multiple human malignancies showed IL-10 participated in tumor immunity and exhibited therapeutic potential. The aim of this study is to investigate whether IL-10 interferes with tumor immunity in PTC with concomitant HT. Expression of IL-10 and major histocompatibility complex (MHC) class Ⅰ were compared with PTC tissues with or without concomitant HT. PTC cell lines K1 and TPC-1 were stimulated with IL-10 and analyzed for MHC class Ⅰ expression afterward. T-cell activation, production of IL-2 and interferon (IFN)-γ and programmed death-1 (PD-1) expression were assessed by coculture of donor peripheral blood lymphocytes (PBLs) with IL-10-pretreated PTC cells. Programmed death-ligand 1 (PD-L1) expression was measured in PTC tissues and IL-10-pretreated cells of K1 and TPC-1. Increased levels of IL-10 and MHC class Ⅰ were observed in PTC with concomitant HT. IL-10 stimulation increased MHC class Ⅰ expression of PTC cells in vitro. Coculture of PBLs with IL-10-pretreated PTC cells enhanced T-cell activation (% cluster of differentiation [CD]25+ of CD3+T cells) and increased IL-2 production along with decreased IFN-γ secretion and PD-1 expression. Reduced PD-L1 expression was seen in PTC + HT tissue samples and IL-10-stimulated PTC cell lines. Elevated IL-10 expression in PTC with concomitant HT restores MHC class Ⅰ expression and interferes with tumor immunity. The potential mechanism of IL-10 in tumor immunity needs further investigation.


Asunto(s)
Genes MHC Clase I/efectos de los fármacos , Enfermedad de Hashimoto/genética , Interleucina-10/farmacología , Activación de Linfocitos/efectos de los fármacos , Cáncer Papilar Tiroideo/genética , Neoplasias de la Tiroides/genética , Adulto , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Células Cultivadas , Estudios de Cohortes , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Enfermedad de Hashimoto/complicaciones , Enfermedad de Hashimoto/inmunología , Enfermedad de Hashimoto/patología , Humanos , Interleucina-10/genética , Interleucina-10/metabolismo , Activación de Linfocitos/genética , Masculino , Persona de Mediana Edad , Linfocitos T/efectos de los fármacos , Linfocitos T/fisiología , Cáncer Papilar Tiroideo/complicaciones , Cáncer Papilar Tiroideo/inmunología , Cáncer Papilar Tiroideo/patología , Neoplasias de la Tiroides/complicaciones , Neoplasias de la Tiroides/inmunología , Neoplasias de la Tiroides/patología , Escape del Tumor/efectos de los fármacos , Escape del Tumor/genética , Adulto Joven
12.
Nat Chem ; 12(1): 90-97, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31792388

RESUMEN

Topological transitions between considerably different phases typically require harsh conditions to collectively break chemical bonds and overcome the stress caused to the original structure by altering its correlated bond environment. In this work we present a case system that can achieve rapid rearrangement of the whole lattice of a metal-organic framework through a domino alteration of the bond connectivity under mild conditions. The system transforms from a disordered metal-organic framework with low porosity to a highly porous and crystalline isomer within 40 s following activation (solvent exchange and desolvation), resulting in a substantial increase in surface area from 725 to 2,749 m2 g-1. Spectroscopic measurements show that this counter-intuitive lattice rearrangement involves a metastable intermediate that results from solvent removal on coordinatively unsaturated metal sites. This disordered-crystalline switch between two topological distinct metal-organic frameworks is shown to be reversible over four cycles through activation and reimmersion in polar solvents.

13.
Chem Commun (Camb) ; 55(31): 4475-4478, 2019 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-30810146

RESUMEN

A strategy for fabricating zirconium oxide doped nanoporous carbons derived from metal-organic gels (MOGs) is reported. For the first time, the achievement of metastable ZrO2-NPCs is demonstrated. The direct pyrolysis of MOGs provided new perspective in developing metal oxide-doped NPCs and circumvented the shortcomings of existing methods in synthesizing metastable ZrO2 doped NPCs.

14.
Chemistry ; 24(53): 14044-14047, 2018 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-29923252

RESUMEN

In this study, the adsorption behavior of different metal centers in analogous M-1,4-NDC frameworks (1,4-NDC=1,4-naphthalenedicarboxylate) towards guest molecules through simulation studies and experimental studies is reported. Simulation studies showed that the adsorption behavior of analogous M-1,4-NDC is affected by the atomic radius of the metal center, which was found to be in agreement with the experimental studies.

15.
Chemistry ; 24(38): 9598-9605, 2018 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-29745473

RESUMEN

A novel and facile strategy in developing a water stable magnetic metal-organic framework nanocomposite (Fe3 O4 @MOF) is herein reported, in which a Keggin polyoxometalate, phosphotungstic acid (HPW), was encapsulated within the MOF framework via one-pot synthesis method. The combination of HPW-embedded MOF and Fe3 O4 endowed the composite with high surface area, strong UV absorption, good hydrophilicity, and enhanced water stability. With these unique properties, the Fe3 O4 @MOF embedded HPW served as adsorbent as well as matrix for SALDI-MS (surface-assisted laser desorption ionization mass spectrometry) analysis of polar and non-polar compounds. The synergistic effect of Fe3 O4 and MOF showed an interference-free background at low mass region than the pristine MOF or Fe3 O4 counterparts. This simple approach can be used as new platform in developing magnetic MOF composites without the time consuming and labor-intensive preparation.

16.
J Chromatogr A ; 1539: 12-18, 2018 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-29402430

RESUMEN

In this study, activated carbon-organic polymer (AC-polymer) extraction columns were prepared via microwave-assisted polymerization. The AC-polymer was applied in polymer monolith microextraction (PMME) of phenolic acids (PAs) in food samples. Structural characterization using Raman and Fourier transform infrared (FTIR) spectroscopy revealed the successful incorporation of AC into polymer monolith. In contrast to neat polymer in which low extraction efficiency (17.0-57.7%) was observed, the AC-polymer (8 mg AC, 4 cm column length) afforded better extraction efficiency for PAs ranging from 75.8 to 99.8% for intra-day with less than 1.4% relative standard deviations (RSDs) and inter-day precision ranging from 74.3 to 100.1% (<2.7% RSDs). The extraction efficiency for column-to-column were found to be in the range of 72.8-100.5% (<2.0% RSDs) (n = 3). Under the optimized conditions, the AC-polymer monolithic column was successfully applied in PMME of PAs in fruit wine and cranberry juice samples at concentrations of <4.8 mg L-1 and 26.54 mg L-1, respectively.


Asunto(s)
Carbono/química , Análisis de los Alimentos/instrumentación , Análisis de los Alimentos/métodos , Hidroxibenzoatos/aislamiento & purificación , Polímeros/química , Vino/análisis , Jugos de Frutas y Vegetales/análisis , Microondas , Polimerizacion , Vaccinium macrocarpon/química
17.
ChemSusChem ; 10(7): 1364-1369, 2017 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-28195433

RESUMEN

In this study, nanoporous carbon (NPC) derived from metal-organic framework was used as support for the immobilization of Burkholderia cepacia lipase. The decorated aluminum oxide within the mesoporous NPC improved the enzyme loading efficiency as well as the catalytic ability for the transesterification of soybean oil, thus making it a promising green and sustainable catalytic system for industrial application.


Asunto(s)
Biocombustibles , Carbono/química , Enzimas Inmovilizadas/química , Lipasa/química , Nanoporos , Compuestos Organometálicos/química , Burkholderia cepacia/enzimología , Técnicas de Química Sintética , Enzimas Inmovilizadas/metabolismo , Esterificación , Lipasa/metabolismo
18.
Small ; 12(15): 2057-66, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26913971

RESUMEN

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) represents a powerful tool for the analysis of biomolecules, synthetic polymers, and even small organic compounds; its performances largely depend on the type of matrix materials utilized. Here, for the first time the employment of nanoporous carbons derived from metal-organic frameworks (MOFs) as novel matrices for SALDI-MS is demonstrated. The nanoporous carbons derived from MOFs not only circumvent the shortcomings of existing matrix materials but also demonstrate much higher efficiency of laser desorption/ionization for various compounds than any other nanoporous carbons reported so far. A new perspective for the development of matrix materials for SALDI-MS application is therefore provided.


Asunto(s)
Carbono/química , Metales/química , Nanoporos , Compuestos Orgánicos/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Adsorción , Interacciones Hidrofóbicas e Hidrofílicas , Nanoporos/ultraestructura , Espectroscopía de Fotoelectrones , Espectrometría Raman , Vapor , Temperatura , Difracción de Rayos X
19.
J Chromatogr A ; 1428: 336-45, 2016 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-26363948

RESUMEN

In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80µgL(-1) and 14-270µgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4µgL(-1) and 111.7-201.2µgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives.


Asunto(s)
Carbón Orgánico/química , Cromatografía Capilar Electrocinética Micelar , Análisis de los Alimentos/métodos , Imidazoles/análisis , Polímeros/química , Microextracción en Fase Sólida , Imidazoles/química , Límite de Detección
20.
J Chromatogr A ; 1428: 236-45, 2016 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-26065570

RESUMEN

In this study, aluminum based metal-organic framework (Al-MOF)-organic polymer monoliths were prepared via microwave-assisted polymerization of ethylene dimethacrylate (EDMA), butyl methacrylate (BMA) with different weight percentages of Al-MOF (MIL-53; 37.5-62.5%) and subsequently utilized as sorbent in solid-phase microextraction (SPME) of penicillins (penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin). The Al-MOF-polymer was characterized using Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM-energy-dispersive X-ray spectroscopy (SEM-EDS) to clarify the retained crystalline structure well as the homogeneous dispersion of Al-MOF (MIL-53) in polymer monolith. The developed Al-MOF-polymer (MIL-53) monolithic column was evaluated according to its extraction recovery of penicillins. Several parameters affecting the extraction recoveries of penicillins using fabricated Al-MOF-polymer (MIL-53) monolithic column including different MIL-53 weight percentages, column length, pH, desorption solvent, and mobile phase flow rate were investigated. For comparison, different Al-based MOFs (MIL-68, CYCU-4 and DUT-5) were fabricated using the optimized condition for MIL-53-polymer (sample matrix at pH 3, 200µL desorption volume using methanol, 37.5% of MOF, 4-cm column length at 0.100mLmin(-1) flow rate). Among all the Al-MOF-polymers, MIL-53(Al)-polymer still afforded the best extraction recovery for penicillins ranging from 90.5 to 95.7% for intra-day with less than 3.5% relative standard deviations (RSDs) and inter-day precision were in the range of 90.7-97.6% with less than 4.2% RSDs. Meanwhile, the recoveries for column-to-column were in the range of 89.5-93.5% (<3.4% RSDs) while 88.5-90.5% (<5.8% RSDs) for batch-to-batch (n=3). Under the optimal conditions, the limit of detections were in the range of 0.06-0.26µgL(-1) and limit of quantifications between 0.20 and 0.87µgL(-1). Finally, the MIL-53-polymer was applied for the extraction of penicillin in river water and milk by spiking trace-level penicillin for as low as 50µgL(-1) and 100µgL(-1) with recoveries ranging from 80.8% to 90.9% (<6.7% RSDs) in river water and 81.1% to 100.7% (<7.1% RSDs) in milk sample, respectively.


Asunto(s)
Aluminio/química , Monitoreo del Ambiente/métodos , Análisis de los Alimentos/métodos , Leche/química , Penicilinas/análisis , Polímeros/química , Ríos/química , Animales , Metacrilatos/química , Polimerizacion , Microextracción en Fase Sólida , Difracción de Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...