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1.
Biosens Bioelectron ; 148: 111739, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31731075

RESUMO

A competitive-type PEC immunosensor for 17ß-estradiol (E2) detection was successfully fabricated using ZnIn2S4@NH2-MIL-125(Ti) composite as matrix. The excellent PEC behavior of ZnIn2S4@NH2-MIL-125(Ti) composite could be attributed to that the Ti4+-Ti3+ intervalence cycles in the titanium oxo-cluster of NH2-MIL-125(Ti) as well as the matching energy level between ZnIn2S4 and NH2-MIL-125(Ti) promote the migration and separation of photocarrier. Besides, polydopamine (PDA) with abundant amino- and quinone-groups was selected to further improve the PEC signals and capture antibody, which implement through the covalent bonding of PDA and BSA-E2 or carboxyl-group functionalized Mn:ZnCdS QDs in the competitive-type strategy. Concretely, the quinone functional groups in PDA film was applied to immobilize BSA-E2 through Michael reactions, and the PDA nanosphere loaded Mn:ZnCdS quantum dot (PDA NS/Mn:ZnCdS QDs) was used as antibodies' labels to amplify PEC signals. After PDA NS/Mn:ZnCdS-anti-E2 immobilized on the modified electrode, a remarkable increase of photocurrent signal was observed owing to the specific bonding of antigen and antibody. Based on the competitive binding of PDA NS/Mn:ZnCdS-anti-E2 with either free E2 or bovine serum albumin (BSA)-E2 causing the change of the photocurrent signal, the standard sample free E2 could be accuracy detect. Under optimal conditions, the competitive-type PEC immunosensor exhibited the linear range from 0.0005 ng/mL to 20 ng/mL and a limit detection of 0.3 pg/mL (S/N = 3). Meanwhile, the acceptable stability, selectivity and reproducibility of the proposed PEC immunosensing platform indicating the promising detection of small molecular environmental pollutants.


Assuntos
Técnicas Biossensoriais/métodos , Estradiol/análise , Indóis/química , Nanocompostos/química , Polímeros/química , Titânio/química , Poluentes Químicos da Água/análise , Anticorpos Imobilizados/química , Compostos de Cádmio/química , Técnicas Eletroquímicas/métodos , Imunoensaio/métodos , Limite de Detecção , Dietilamida do Ácido Lisérgico/análogos & derivados , Dietilamida do Ácido Lisérgico/química , Nanocompostos/ultraestrutura , Pontos Quânticos/química , Pontos Quânticos/ultraestrutura , Sulfetos/química , Água/análise , Zinco/química
2.
Int J Nanomedicine ; 14: 9577-9586, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31824152

RESUMO

Purpose: Quantum dots (QDs) are widely used semiconductor nanomaterials. Indium phosphide/zinc sulfide (InP/ZnS) QDs are becoming potential alternatives to toxic heavy metal-containing QDs. However, the potential toxicity and, in particular, the immunotoxicity of InP/ZnS QDs are unknown. This study aimed to investigate the impacts of InP/ZnS QDs on inflammatory responses both in vivo and in vitro. Methods: Mice and mouse bone marrow-derived macrophages (BMMs) were exposed to polyethylene glycol (PEG) coated InP/ZnS QDs. The infiltration of neutrophils and the release of interleukin-6 (IL-6) were measured using a hematology analyzer and an enzyme-linked immunosorbent assay (ELISA) for the in vivo test. Cytotoxicity, IL-6 secretion, oxidative stress and endoplasmic reticulum (ER) stress were studied in the BMMs, and then, inhibitors of oxidative stress and ER stress were used to explore the mechanism of the InP/ZnS QDs. Results: We found that 20 mg/kg PEG-InP/ZnS QDs increased the number of neutrophils and the levels of IL-6 in both peritoneal lavage fluids and blood, which indicated acute phase inflammation in the mice. PEG-InP/ZnS QDs also activated the BMMs and increased the production of IL-6. In addition, PEG-InP/ZnS QDs triggered oxidative stress and the ER stress-related PERK-ATF4 pathway in the BMMs. Moreover, the inflammatory response caused by the PEG-InP/ZnS QDs could be attenuated in the macrophages by blocking the oxidative stress or the ER stress with inhibitors. Conclusion: InP/ZnS QDs can activate macrophages and induce acute phase inflammation both in vivo and in vitro, which may be regulated by oxidative stress and ER stress. Our present work is expected to help clarify the biosafety of InP/ZnS QDs and promote their safe application in biomedical and engineering fields.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Índio/farmacologia , Macrófagos/patologia , Estresse Oxidativo/efeitos dos fármacos , Fosfinas/farmacologia , Pontos Quânticos/química , Sulfetos/farmacologia , Compostos de Zinco/farmacologia , Animais , Feminino , Depuradores de Radicais Livres/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/genética , Inflamação/patologia , Interleucina-6/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Pontos Quânticos/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo
3.
Int J Nanomedicine ; 14: 9513-9524, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31819447

RESUMO

Background: Early diagnosis of renal cell carcinoma is extremely significant for the effective treatment of kidney cancer. The development of AS1411 aptamer modified Mn-MoS2 QDs provides a promising fluorescence/magnetic resonance (MR) dual-modal imaging probe for the precise diagnosis of renal clear cell carcinoma. Methods: In this work, Mn-MoS2 QDs were synthesized through a simple "bottom-up" one-step hydrothermal method. AS1411 aptamer was modified on the Mn-MoS2 QDs to improve the specificity to renal cell carcinoma. The characteristics of Mn-MoS2 QDs were confirmed by transmission electronic microscopy (TEM), atomic force microscope (AFM), X-ray photoelectron spectrometer (XPS), photoluminescence (PL) emission spectra, etc. Cellular fluorescence labelling was investigated using the Mn-MoS2 QDs and AS1411-Mn-MoS2 QDs. The T1-weighted MR imaging was assessed by the in vitro MR cell imaging and in vivo MR imaging. Finally, the long-term toxicity of Mn-MoS2 QDs was investigated by the hematology and histological analysis. Results: The prepared Mn-MoS2 QDs exhibited excellent aqueous property, intense fluorescence, low toxicity, high quantum yield of 41.45% and high T1 relaxivity of 16.95 mM-1s-1. After conjugated with AS1411 aptamer, the AS1411-Mn-MoS2 QDs could specifically fluorescently label the renal carcinoma cells and present a specific MRI signal enhancement in the tumor region of mice bearing renal carcinoma tumors. Furthermore, Mn-MoS2 QDs revealed low toxicity to the mice via hematology and histological analysis. Conclusion: These results demonstrated the potential of AS1411-Mn-MoS2 QD as a novel nanoprobe for targeted MR imaging and fluorescence labelling of renal cell carcinoma.


Assuntos
Aptâmeros de Nucleotídeos/química , Carcinoma de Células Renais/diagnóstico por imagem , Dissulfetos/química , Imagem por Ressonância Magnética , Manganês/química , Molibdênio/química , Oligodesoxirribonucleotídeos/química , Pontos Quânticos/química , Coloração e Rotulagem , Animais , Morte Celular , Linhagem Celular Tumoral , Dissulfetos/toxicidade , Feminino , Fluorescência , Humanos , Neoplasias Renais/diagnóstico por imagem , Manganês/toxicidade , Camundongos , Molibdênio/toxicidade , Pontos Quânticos/toxicidade , Pontos Quânticos/ultraestrutura
4.
Molecules ; 24(22)2019 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-31744056

RESUMO

Gout is a disease with a high incidence and causing great harm, and the current treatment drugs are not satisfactory. In this study, novel water-soluble carbon dots (CDs) with anti-gout effect, named Puerariae lobatae Radix CDs (PLR-CDs), are reported. PLR-CDs were synthesized with an improved pyrolysis method at 300 °C, and their characterization was performed with multifaceted approaches, such as transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) and Fourier-transform infrared (FTIR) spectroscopy. In addition, the biocompatibility of PLR-CDs was studied using the cell counting kit (CCK)-8 in LO2 cells and RAW264.7 cells, and the anti-gout activity of PLR-CDs was examined on animal models of hyperuricemia and gouty arthritis. The characterization of PLR-CDs indicated that they were nearly spherical, with diameters ranging from 3.0 to 10.0 nm, and the lattice spacing was 0.283 nm. The toxicity experiment revealed that PLR-CDs were non-poisonous for LO2 cells and RAW264.7 cells at concentrations below 250 µg/mL. The results of pharmacodynamic experiments showed that PLR-CDs could lower the blood uric acid level in model rats by inhibiting the activity of xanthine oxidase and reduce the degree of swelling and pathological damage of gouty arthritis. Thus, PLR-CDs with anti-gout biological activity and good biocompatibility have the prospect of clinical application for the treatment of gout.


Assuntos
Carbono/química , Supressores da Gota/química , Supressores da Gota/farmacologia , Pueraria/química , Pontos Quânticos/química , Animais , Biópsia , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Gota/tratamento farmacológico , Gota/etiologia , Gota/patologia , Camundongos , Nanopartículas/química , Nanopartículas/ultraestrutura , Pontos Quânticos/ultraestrutura , Células RAW 264.7 , Ratos , Análise Espectral
5.
Int J Nanomedicine ; 14: 7065-7078, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507320

RESUMO

Background:  Metal-free, water-soluble and highly stable meso-tetra-(4-sulfonatophenyl) porphyrin (TPPS4) has been studied for their singlet oxygen quantum yield. However, TPPS4 suffers from inherent shortcomings. To address these, TPPS4 was conjugated to ternary copper indium sulphide/ zinc sulphide (CuInS2/ZnS) quantum dots (QDs). Purpose:  We herein report for the first time the synthesis of TPPS4-CuInS/ZnS QDs conjugate as an improved photosensitizer. Methods:  Water-soluble TPPS4 was synthesized from tetraphenylporphyrin (TPPH2) after silica-gel purification. The CuInS/ZnS QDs were synthesized by hydrothermal method at a Cu:In ratio of 1:4. The porphyrin-QDs conjugate was formed via the daggling sulfonyl bond of the porphyrin and amine bond of the QDs. The effect of pH on the optical properties of TPPS4 was evaluated. The effect of Zn:Cu + In ratio on the ZnS shell passivation was examined to reduce structural defects on the as-synthesized QDs. Results : Various spectroscopic techniques were used to confirm the successful conversion of the organic TPPH2 to water-soluble TPPS4. The singlet oxygen generation evaluation shows an improved singlet oxygen quantum yield from 0.19 for the porphyrin (TPPS4) alone to 0.69 after conjugation (CuInS/ZnS-TPPS4) with an increase in the reaction rate constant (k (s-1)).


Assuntos
Cobre/química , Índio/química , Porfirinas/síntese química , Porfirinas/farmacologia , Pontos Quânticos/química , Sulfetos/síntese química , Compostos de Zinco/síntese química , Concentração de Íons de Hidrogênio , Fenômenos Ópticos , Fármacos Fotossensibilizantes , Porfirinas/química , Pontos Quânticos/ultraestrutura , Oxigênio Singlete/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos/química , Temperatura , Compostos de Zinco/química
6.
Mater Sci Eng C Mater Biol Appl ; 105: 110132, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546396

RESUMO

In this work, nitrogen and sulfur dual-doped carbon quantum dots (N,S-CDs) from naturally renewable biomaterial fungus fibers were prepared by a biosynthesis and hydrothermal method. The N,S-CDs displayed good water solubility, excellent stability, high quantum yield (QY = 28.11%) as well as remarkable features for fluorescence quenching-based detection and cellular imaging of cancer cells. It was worth mentioning that the heteroatoms doped carbon quantum dots made from the fungus fibers had a satisfactory QY and could be used as a selective, efficient, and sensitive fluorescent probe to determine tetracyclines by the synergistic effects of static quenching and internal filtration effect. The probe demonstrated a wide linear range and low detection limit. For tetracycline, the linear range was 0.5 µM to 47.6 µM, and the corresponding detection limit was 15.6 nM. Significantly, the test papers prepared by using N,S-CDs could detect tetracyclines in aquiculture wastewater rapidly. The produced N,S-CDs did not affect the cell viability and showed great promises for cellular imaging.


Assuntos
Carbono/química , Fungos/química , Imageamento Tridimensional , Neoplasias/diagnóstico por imagem , Nitrogênio/química , Pontos Quânticos/química , Enxofre/química , Tetraciclinas/análise , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Neoplasias/patologia , Tamanho da Partícula , Pontos Quânticos/ultraestrutura , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Tetraciclinas/farmacologia , Águas Residuárias/química
7.
ACS Appl Mater Interfaces ; 11(36): 33033-33042, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31436947

RESUMO

Reverse osmosis (RO) is an emerging membrane technology for disinfection byproducts (DBPs) removal. However, the chlorine-resistance and DBPs removal performance of thin film composite (TFC) polyamide membranes should be simultaneously improved when used in chlorinated drinking water. This study was dedicated to synthesize a novel nanoparticle of ZIF-8 with carbon dots (CDs@ZIF-8) and then modify thin film nanocomposite (TFN) membranes to enhance their performance in removing four trihalomethanes (THMs), four haloacetonitriles (HANs), and two haloketones (HKs) in chlorinated drinking water. The fabricated CDs@ZIF-8 nanoparticles and TFN membranes were characterized by FESEM, AFM, XPS, water contact angle, membrane surface potential, and a three-dimensional excitation-emission matrix (EEM) to investigate the influences of CDs@ZIF-8 on TFN membranes. After chlorination, percentage reduction in salt rejection of the CDs@ZIF-8 TFN membranes was lower than that of the TFC membranes due to hydrogen bonding between CDs and polyamide, replacing amidic hydrogen with chlorine, rendering the membrane less susceptible to chlorine attack and enhancing chlorine-resistance. Results also showed that the rejection of DBPs in chlorinated drinking water by CDs@ZIF-8 TFN membranes was more than 95%. The large surface area and abundant oxygen-containing groups of CDs@ZIF-8 made the nanoparticle act as a nanocarbon filler with high adsorption capacity of DBPs. The enhanced performances of chlorine-resistance and DBPs removal by CDs@ZIF-8 TFN membranes determined in this study provided valuable insights on the DBPs control in chlorinated drinking water by RO membranes.


Assuntos
Cloro/análise , Desinfecção , Água Potável/química , Membranas Artificiais , Nanocompostos/química , Nylons/química , Pontos Quânticos/química , Compostos de Zinco/química , Carbono/química , Espectroscopia Fotoeletrônica , Pontos Quânticos/ultraestrutura , Espectrofotometria Ultravioleta , Poluentes Químicos da Água/isolamento & purificação
8.
Anal Bioanal Chem ; 411(25): 6733-6743, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31402423

RESUMO

An immunomagnetic optical probe based on a core/shell magnetic nanoparticle-quantum dot was fabricated for detection of Streptococcus agalactiae, the causative agent of pneumonia and meningitis in newborns. The silica-coated magnetic nanoparticles conjugated with anti-S. agalactiae monoclonal antibody provided high specificity for pre-enrichment of bacteria from biological samples with a complex matrix such as milk. Compared with conventional methods such as culture and molecular techniques, the combination of fluorescent quantum dot and magnetic nanoparticle enhanced the sensitivity and speed of bacterial identification. The bio-functionalized fluorescent-magnetic nanoparticles were characterized by TEM, SEM, VSM, XRD, DLS, and FTIR and applied to the detection of S. agalactiae with a limit of 10 and 102 CFU/mL in PBS and milk, respectively. This immunomagnetic optical probe can be used for rapid isolation, sensitive, and specific detection of targeted bacteria without any treatment in clinical and animal samples in the presence of other infectious agents.


Assuntos
Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Nanopartículas de Magnetita/química , Leite/microbiologia , Streptococcus agalactiae/isolamento & purificação , Animais , Anticorpos Imobilizados/química , Análise de Alimentos/métodos , Separação Imunomagnética/métodos , Nanopartículas de Magnetita/ultraestrutura , Microscopia de Fluorescência/métodos , Pontos Quânticos/química , Pontos Quânticos/ultraestrutura , Dióxido de Silício/química , Espectrometria de Fluorescência/métodos , Infecções Estreptocócicas/microbiologia
9.
Colloids Surf B Biointerfaces ; 182: 110389, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31377610

RESUMO

Developing novel aqueous-soluble quantum dots (QDs) can create new opportunities for better biological utilization. In the present work, novel, high emissive and biocompatible N-acetyl-L-cysteine-capped Ag-In-S QDs (as an I-III-VI structure) were prepared in a facile and straightforward way. The dominance of the strong confinement regime was observed due to the very small size of nanoparticles, which was smaller than their excitonic Bohr radius. To prepare reproducible Ag-In-S QDs, their emission characteristics were improved by optimizing the experimental variables which resulted in the enhancement of their emission quantum yield to near 32% at 615 nm. The absorption and emission results support the contribution of band edge-independent radiative recombination pathways for charge carriers in the prepared Ag-In-S QDs. The possible mechanisms for such donor-acceptor recombination were also discussed. To explore the antibacterial ability of the Ag-In-S QDs, their bactericidal activity was evaluated against different types of Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Salmonella enterica) bacteria. Precise measurements confirmed a remarkable bactericidal activity of Ag-In-S QDs against the different pathogenic bacteria even at low concentration of QDs (15 µg/mL). It was found that the QDs are more effective on Gram-negative bacteria. While the preparation method was simple and cost-effective, the as-synthesized QDs were highly emissive and stable with significant antibacterial activity. This demonstrates the great potential of present Ag-In-S QDs for future hygienic and medical purposes.


Assuntos
Antibacterianos/administração & dosagem , Bactérias/efeitos dos fármacos , Pontos Quânticos/administração & dosagem , Prata/química , Água/química , Acetilcisteína/química , Antibacterianos/síntese química , Antibacterianos/química , Bacillus subtilis/efeitos dos fármacos , Bactérias/classificação , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Microscopia Eletrônica de Transmissão , Pontos Quânticos/química , Pontos Quânticos/ultraestrutura , Salmonella enterica/efeitos dos fármacos , Solubilidade , Especificidade da Espécie , Análise Espectral , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
10.
ACS Appl Mater Interfaces ; 11(36): 32647-32658, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31381288

RESUMO

Red-emitting carbon dots (CDs) have attracted tremendous attention due to their wide applications in areas including imaging, sensing, drug delivery, and cancer therapy. However, it is still highly challenging for red-emitting CDs to simultaneously achieve high quantum yields (QYs), nucleus targeting, and super-resolution fluorescence imaging (especially the stimulated emission depletion (STED) imaging). Here, it is found that the addition of varied metal ions during the hydrothermal treatment of p-phenylenediamine (pPDA) leads to the formation of fluorescent CDs with emission wavelengths up to 700 nm. Strikingly, although metal ions play a crucial role in the synthesis of CDs with varied QYs, they are absent in the formed CDs, that is, the obtained CDs are metal-free, and the metal ions play a role similar to a "catalyst" during the CD formation. Besides, using pPDA and nickel ions (Ni2+) as raw materials, we prepare Ni-pPCDs which have the highest QY and exhibit various excellent fluorescence properties including excitation-independent emission (at ∼605 nm), good photostability, polarity sensitivity, and ribonucleic acid responsiveness. In vitro and in vivo experiments demonstrate that Ni-pPCDs are highly biocompatible and can realize real-time, wash-free, and high-resolution imaging of cell nuclei and high-contrast imaging of tumor-bearing mice and zebrafish. In summary, the present work may hold great promise in the synthesis and applications of red emissive CDs.


Assuntos
Carbono/química , Nucléolo Celular/metabolismo , Rastreamento de Células , Imagem Molecular , Pontos Quânticos/química , Células A549 , Animais , DNA/metabolismo , Endocitose , Humanos , Camundongos , Níquel/química , Fenilenodiaminas/química , Espectroscopia Fotoeletrônica , Pontos Quânticos/ultraestrutura , RNA/metabolismo , Espectrometria de Fluorescência , Peixe-Zebra
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117366, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31323493

RESUMO

In this work, we presented a facile microwave method to prepare blue emitting carbon dots (CDs) using lysine as carbon source and realized the specific detection of seven types of antibiotics by CDs and Al3+ ions via a two-step method. The CDs have good solubility in water and their excitation spectra are exactly coincided with the absorption of some typical antibiotics, which leads to the fluorescence quenching of CDs (OFF state). The inhibition mechanism of fluorescence is induced by the combination of inner filtering effect (IFE) and static quenching effect (SQE). In addition, the quenched fluorescence can be recovered by adding Al3+ ions (On state), and seven types of antibiotics can be distinguished exactly according to the emission peak position and intensity. It not only provides a new and convenient method for the detection of antibiotics, but also provides a new idea for the further application of CDs in optical sensing.


Assuntos
Alumínio/química , Antibacterianos/análise , Carbono/química , Pontos Quânticos/química , Íons , Tamanho da Partícula , Pontos Quânticos/ultraestrutura , Espectrofotometria Ultravioleta
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117349, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31319275

RESUMO

The new ionic liquid capped CdS quantum dots (IL-CdS QDs) as a fluorescent probe was successfully synthesized by a hydrothermal method in a one step process and used for the facile and sensitive determination of florfenicol (FLF) in aqueous media. The new ionic liquid 3-(2-[(5-amino-1,3,4-thiadiazol-2-yl)thio]ethyl)-1-methyl-1H-imidazol-3-ium chloride (IL) was synthesized by introducing 5-amino-1,3,4-thiadiazole-2-thiol as a ligand onto the alkyl chain of the 1-chloroethyl-3-methylimidazolium chloride ILs. This task specific ionic liquid reagent was used for the capping of CdS QDs which played the role of recognition element of FLF. The IL-CdS QDs were characterized by Ultra Violet-Visible absorption -spectroscopy (UV-Vis absorption spectroscopy), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Quenching of fluorescence intensity of the IL-CdS QDs was in proportion to the addition of FLF concentration. Under the optimum conditions, the fluorescence intensity ratio of IL-CdS QDs in the presence and absence of FLF versus FLF concentrations gave a linear response according to the Stern-Volmer equation from 0.1 to 20 µg mL-1 (0.3 to 56 µmol L-1) with a limit of detection 0.035 µg mL-1 (0.098 µmol L-1). The developed method was applied to the determination of FLF in fish and chicken meats with satisfactory results. This method revealed some advantages such as high sensitivity, precision and wide linear range to FLF. The proposed method can be utilized for rapid screening the quality of meat products.


Assuntos
Compostos de Cádmio/química , Corantes Fluorescentes/química , Líquidos Iônicos/química , Carne/análise , Pontos Quânticos/química , Sulfetos/química , Tianfenicol/análogos & derivados , Animais , Galinhas , Peixes , Concentração de Íons de Hidrogênio , Pontos Quânticos/ultraestrutura , Espectrometria de Fluorescência , Tianfenicol/análise , Fatores de Tempo
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 223: 117325, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31280127

RESUMO

We report a facile one step in-situ synthesis of amino-functionalized graphene dots. These quantum dots were employed for the detection of glucose in both standard aqueous solutions and commercially available fruit juice to assess its practicability. The characterization of the quantum dots revealed that they were decorated with amine functionality. Additionally, the interaction between glucose and amine functionalized graphene quantum dots gave enhancement in the UV-vis absorption and photoluminescence (PL) due to aggregation of quantum dots via glucose link. Therefore, the quantum dots were able to detect the concentration of glucose in solution exhibiting linearity from 0.1 to 10 mM and 50-500 mM with a sensitivity transition from 10 mM to 50 mM. The limit of detection for the determination of glucose was found to be 10 µM. This determination was agreed from both UV-Vis absorption and PL spectroscopy. However, the PL emission method of determination was most suited with its very high accuracy of 98.04 ±â€¯1.96% and 97.33 ±â€¯2.67% for the linear range of glucose concentration within 0.1-10 mM and 50-500 mM, respectively. The PL enhancement was highly selective towards glucose in mixture of other form of sugars making it suitable for determining glucose in food samples.


Assuntos
Glucose/análise , Grafite/química , Nitrogênio/química , Pontos Quânticos/química , Espectrofotometria/métodos , Luminescência , Espectroscopia Fotoeletrônica , Pontos Quânticos/ultraestrutura , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Anal Bioanal Chem ; 411(23): 6081-6090, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273411

RESUMO

A nanooptosensor based on the fluorescence quenching of a composite probe was fabricated for the detection of sarafloxacin. The components of the nanocomposite fluorescent probe were a high affinity material of polydopamine polymer (PDA), a selective material of molecularly imprinted polymer (MIP), and optically sensitive quantum dots (QDs). The developed nanocomposite fluorescent probe exhibited excellent selectivity and sensitivity for sarafloxacin. The molecularly imprinted polymer had an imprinting factor (IF) of 8.18 and produced a probe that quenched fluorescence more effectively than a non-imprinted polymer (NIP) probe. The emission intensity of the MIP probe was linearly quenched by sarafloxacin over a range of 0.10 to 15.0 µg L-1 with a determination coefficient (R2) of 0.9966. The developed nanooptosensor had a limit of detection of 0.05 µg L-1. The optosensor detected sarafloxacin in chicken meat samples with recoveries ranging from 82.8 to 99.1% with an RSD below 3%. The found concentrations in spiked samples were compared well with recoveries obtained by HPLC method of detection. This developed nanooptosensor is simple to operate and cost-effective and the analytical procedure is rapid. Graphical abstract.


Assuntos
Antibacterianos/análise , Ciprofloxacino/análogos & derivados , Contaminação de Alimentos/análise , Indóis/química , Carne/análise , Impressão Molecular/métodos , Polímeros/química , Pontos Quânticos/química , Animais , Galinhas/metabolismo , Ciprofloxacino/análise , Corantes Fluorescentes/química , Limite de Detecção , Aves Domésticas/metabolismo , Pontos Quânticos/ultraestrutura
15.
Nano Lett ; 19(8): 5762-5768, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31309825

RESUMO

Using a novel method developed to quantify the polarizability of photoluminescent nanoparticles in water, we present experimental observations of the extraordinary polarizability exhibited by nanoparticles of commensurate size with the Debye screening length, confirming previously reported theory. Semiconductor quantum dots (QDs) are ideal model nanoparticles to demonstrate this assay, due to their tunable size and bright photoluminescence. This assay is based upon microfluidic chambers with microelectrodes that generate trapping potentials that are weaker than thermal energy. By comparing the local electric field strength and variations in QD concentration, their polarizability was computed and found to agree with estimates based upon the hydrodynamic diameter found using light scattering. Strikingly, the polarizability of the nanoparticles increased 30-fold in low salt conditions compared to high salt conditions due to the increased thickness of the Debye layer relative to the particle radius. In addition to providing evidence that corroborates theoretical work studying direct solutions to the Poisson-Nernst-Planck equations, these observations provide an explanation for the previously observed conductivity dependence of biomolecule polarizability. As the polarizability of nanoparticles is of high importance to the electrically directed assembly of particles, as well as their interactions with other materials in complex environments, we anticipate that these results will be highly relevant to ongoing efforts in materials by design and nanomedicine.


Assuntos
Pontos Quânticos/química , Condutividade Elétrica , Eletricidade , Microscopia de Fluorescência/métodos , Tamanho da Partícula , Pontos Quânticos/ultraestrutura , Eletricidade Estática
16.
Colloids Surf B Biointerfaces ; 182: 110348, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31301579

RESUMO

Bioimaging probes incorporating quantum dots (QDs) are important for identifying organelles and monitoring their movement/location in living cells. Organelle specificity can be accomplished by functionalizing probe surfaces with chemical groups that can react with antibodies capable of targeting specific organelle-protein epitopes. Here, such a bioprobe is generated by encapsulating ZnS-capped CdSe QDs within polystyrene (PS) nanocolloids via Pickering miniemulsion using laponite nanoclay platelets as solid-stabilizers. The surfaces of these platelets are modified with aminopropyltriethoxysilane (APTES), and biotinylated by reacting sulfo-NHS-Biotin via the APTES amine group. Surface functionalization and bioconjugation are confirmed using X-ray photoelectron spectroscopy. The number of sites available on Streptavidin for Biotin binding is determined using a competitive HABA assay to optimize the bioconjugation protocol. The PS-encapsulated QDs (PS-QDs) nanocolloids are 50-200 nm in diameter and colloidally stable, as evidenced by transmission electron microscopy and ζ-potential measurements, respectively. Spherical particle shape is confirmed by scanning electron microscopy. Transmission electron microscopy also showed the nanoclay platelets on the surface of QD-encapsulating latex particles. The PS-QDs particles are easily dispersed in water and exhibit long-term photostability over various conditions. Cell viability of >95% is observed for NIH-3T3 cells after 72-h exposure to PS-QDs nanocolloids, with no cytotoxicity to living cells, even at 0.1 mg mL-1. NIH-3T3 cellular uptake and internalization are confirmed by confocal microscopy, with PS-QDs fluorescence within cells remaining high even after 24-h exposure, demonstrating the applicability of PS-QDs nanocolloids as long-lived fluorescent bioprobes for in vitro intracellular imaging.


Assuntos
Corantes Fluorescentes/química , Imagem Molecular/métodos , Imagem Óptica/métodos , Pontos Quânticos/química , Compostos de Selênio/química , Silicatos/química , Compostos de Zinco/química , Animais , Biotina/química , Biotinilação , Sobrevivência Celular/efeitos dos fármacos , Coloides , Composição de Medicamentos/métodos , Humanos , Camundongos , Células NIH 3T3 , Poliestirenos/química , Propilaminas/química , Pontos Quânticos/ultraestrutura , Silanos/química , Estreptavidina/química
17.
Mater Sci Eng C Mater Biol Appl ; 102: 106-112, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31146980

RESUMO

We report highly fluorescent N-doped carbon dots (CDs) synthesized from food waste via one-step hydrothermal carbonization. To study the chemical transition of carbon dots from food wastes, the cat feed stocks driven from food waste were used as the waste model. In the model study, the core of the CDs was successfully self N-doped without extra pre- or post-treatments. The experimental results reveal that the nitrogen in the waste model played an important role in the formation of graphitic N and pyridinic N in the core and functional groups on the surface. Especially, high process temperature (≥180 °C) resulted in high quantum yield as 23% of the CDs from the waste model. To demonstrate the conversion of real food waste into CDs, the hamburger sandwich leftover was used as a precursor for CDs. The food waste driven CDs had similar chemical and fluorescent properties to that of the waste model, having quantum yield of 28%. This study exhibits the food waste driven carbon dots are excellent candidates for fluorescence probe to Fe3+ with high selectivity even under the interference of other metal, and for bio-imaging material with good cell viability over 80%.


Assuntos
Carbono/química , Alimentos , Ferro/análise , Imagem Molecular/métodos , Nitrogênio/química , Pontos Quânticos/química , Resíduos , Ração Animal , Animais , Gatos , Células HCT116 , Humanos , Espectroscopia Fotoeletrônica , Pontos Quânticos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Mater Sci Eng C Mater Biol Appl ; 102: 45-52, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147016

RESUMO

Tyrosinase inhibitors could effectively limit the activity of tyrosinase in melanocytes to reduce the excessive synthesis and deposition of melanin. However, low skin permeability and lacking in targeting greatly restricted their application. Herein, ZnO quantum dots were synthesized by gel-sol method and grafted with BQ-788, which have been employed as transdermal and targeting carrier to delivery ellagic acid to melanocytes. Ellagic acid loaded ZnO quantum dots with the size distribution of around 9 nm could targetedly bind to melanocytes and enter the melanocytes by endocytosis within 1 h. The ellagic acid release behavior was controlled by the decreasing of pH via the rapid dissolution of ZnO. When the concentration of BQ-788/EA@ZnO was 12.5 µg/mL, the inhibition rate on tyrosinase activity and melanin deposition were up to 44.23 ±â€¯4.97% and 37.50 ±â€¯5.23%, respectively. In view of their good biocompatibility, they were of great potential in clinically external application for tyrosinase inhibition.


Assuntos
Ácido Elágico/química , Inibidores Enzimáticos/farmacologia , Melanócitos/enzimologia , Monofenol Mono-Oxigenase/antagonistas & inibidores , Oligopeptídeos/administração & dosagem , Oligopeptídeos/farmacologia , Piperidinas/administração & dosagem , Piperidinas/farmacologia , Pontos Quânticos/química , Óxido de Zinco/química , Administração Cutânea , Adulto , Materiais Biocompatíveis/farmacologia , Células Cultivadas , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos , Endocitose/efeitos dos fármacos , Humanos , Melaninas/metabolismo , Melanócitos/efeitos dos fármacos , Monofenol Mono-Oxigenase/metabolismo , Oligopeptídeos/síntese química , Oligopeptídeos/química , Piperidinas/síntese química , Piperidinas/química , Pontos Quânticos/ultraestrutura , Tirosina/metabolismo , Óxido de Zinco/síntese química
19.
Mater Sci Eng C Mater Biol Appl ; 102: 653-660, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147037

RESUMO

This paper reports an aptamer-based green approach for the electrochemical evaluation of tyrosinamide (Tyr-NH2). In this regard, at the first step, an aqueous synthetic strategy for preparing N-acetyl-l-cysteine (NAC)-capped Ag-In-S (AIS) quantum dots (QDs) with bright yellow/orange emission was developed. The conjugation of AIS QDs to NAC-biomolecules provides opportunities for using them as luminescent contrast agents for living cell tracking and labeling or sensing studies. In the next step, the design stage of the aptasensor, the glassy carbon electrode (GCE) was modified with the AIS QDs and then the Tyr-NH2 special aptamer, which has an amine group at its end, interacts with silver and indium ions at the surface of the AIS QDs and through the formation of covalent bonding of AgN and InN, attaches to the GCE surface modified with the AIS QDs. In this approach, for the first time, NAC-capped AIS QDs have been used to modify the electrode surface in the aptamer-based electrochemical sensor. The response changes of the [Fe(CN)6]4-/3- as redox probe, during the modification of GCE surface, the fabrication and assessment of proposed aptasensing, using the cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy were recorded. The designed aptasensor for the Tyr-NH2 evaluation showed good linearity from 0.01 to 2.81 nM and 2.81-10.81 nM, and low detection limit of 3.34 pM. The obtained results of the stability, reproducibility and selectivity investigations implying that the reported aptasensor as the first aptamer-based electrochemical assay for Tyr-NH2, can be reliable for the determination of Tyr-NH2 in serum samples.


Assuntos
Acetilcisteína/química , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Carbono/química , Técnicas Eletroquímicas/métodos , Vidro/química , Pontos Quânticos/química , Tirosina/análogos & derivados , Espectroscopia Dielétrica , Eletrodos , Humanos , Índio/química , Pontos Quânticos/ultraestrutura , Reprodutibilidade dos Testes , Prata/química , Enxofre/química , Fatores de Tempo , Tirosina/sangue
20.
Mater Sci Eng C Mater Biol Appl ; 102: 917-922, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147063

RESUMO

A simple synthesis strategy was designed and applied to synthesize nitrogen and sulfur co-doped aminated ligninsulfonate/graphene quantum dots (ASL/GQDs) composites using citric acid monohydrate and byproducts of the sulfite-pulping procedure (sodium lignosulfonate). The combination of these two materials improves surface chemical activities and electronic characteristics. As a result,the combination offers excellent photoluminescence properties and sensitivity. The fluorescence intensity of the as-prepared ASL/GQDs composites is more than three times that of the free GQDs. ASL/GQDs based fluorescent probe was applied to sensitively determine Ag+ with a good linearity in a range from 0.005 to 500 µM with a correlation coefficient of 0.99. The method was also used successfully to determine the amount of Ag+ in environmental water samples. Using an MTT assay, the ASL/GQDs have low toxicity and are biocompatible with A549 cells, and may be successfully used to image A549 cells.


Assuntos
Carbono/química , Imagem Óptica/métodos , Prata/análise , Sulfitos/química , Células A549 , Sobrevivência Celular , Grafite/química , Humanos , Íons , Pontos Quânticos/ultraestrutura , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
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