Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42.578
Filtrar
Mais filtros








Intervalo de ano de publicação
1.
J Nanobiotechnology ; 20(1): 6, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34983543

RESUMO

BACKGROUND: Gold nanoparticles (AuNPs) have been widely used in local surface plasmon resonance (LSPR) immunoassays for biomolecule sensing, which is primarily based on two conventional methods: absorption spectra analysis and colorimetry. The low figure of merit (FoM) of the LSPR and high-concentration AuNP requirement restrict their limit of detection (LOD), which is approximately ng to µg mL-1 in antibody detection if there is no other signal or analyte amplification. Improvements in sensitivity have been slow in recent for a long time, and pushing the boundary of the current LOD is a great challenge of current LSPR immunoassays in biosensing. RESULTS: In this work, we developed spectral image contrast-based flow digital nanoplasmon-metry (Flow DiNM) to push the LOD boundary. Comparing the scattering image brightness of AuNPs in two neighboring wavelength bands near the LSPR peak, the peak shift signal is strongly amplified and quickly detected. Introducing digital analysis, the Flow DiNM provides an ultrahigh signal-to-noise ratio and has a lower sample volume requirement. Compared to the conventional analog LSPR immunoassay, Flow DiNM for anti-BSA detection in pure samples has an LOD as low as 1 pg mL-1 within only a 15-min detection time and 500 µL sample volume. Antibody assays against spike proteins of SARS-CoV-2 in artificial saliva that contained various proteins were also conducted to validate the detection of Flow DiNM in complicated samples. Flow DiNM shows significant discrimination in detection with an LOD of 10 pg mL-1 and a broad dynamic detection range of five orders of magnitude. CONCLUSION: Together with the quick readout time and simple operation, this work clearly demonstrated the high sensitivity and selectivity of the developed Flow DiNM in rapid antibody detection. Spectral image contrast and digital analysis further provide a new generation of LSPR immunoassay with AuNPs.


Assuntos
Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , Ressonância de Plasmônio de Superfície/métodos , Anticorpos Antivirais/imunologia , COVID-19/imunologia , Teste Sorológico para COVID-19/instrumentação , Desenho de Equipamento , Ouro/química , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Nanopartículas Metálicas/química , SARS-CoV-2/imunologia , Saliva/virologia , Glicoproteína da Espícula de Coronavírus/imunologia , Ressonância de Plasmônio de Superfície/instrumentação
2.
J Chromatogr A ; 1662: 462729, 2022 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-34998472

RESUMO

In this work, a novel sorbent, based on UVM-7 mesoporous silica doped with Au, has been proposed for organochlorine pesticides extraction. Cartridges containing this material have been applied to the preconcentration of 20 pesticides from water samples, through a solid-phase extraction (SPE) protocol, with their later determination by gas chromatography with an electron capture detector. First, UVM-7 materials were properly characterized by X-ray diffraction, N2 adsorption-desorption, electron microscopy techniques, and UV-Vis spectroscopy, thus confirming their structure and Au incorporation. After optimization of main extraction parameters, recoveries in the range of 80-110% were obtained for most of the analytes, with enrichment factors comprised between 275 and 430. The obtained sensitivity was comparable with other reported methods, with limits of quantification in the range of 0.3-20 ng L-1, thus allowing the determination of these compounds according to European legislation. The developed method has been successfully applied to the analysis of real spiked samples in comparison with a reference method, thus being this sorbent an alternative for organochlorine pesticide enrichment, through a simple, reusable, cheap, and environmentally friendly SPE procedure.


Assuntos
Nanopartículas Metálicas , Praguicidas , Poluentes Químicos da Água , Ouro , Praguicidas/análise , Dióxido de Silício , Extração em Fase Sólida , Água , Poluentes Químicos da Água/análise
3.
Biosens Bioelectron ; 200: 113926, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34990956

RESUMO

In this work, an unprecedented study exploring the role that slight changes into the Pd/Au proportion have in the electrocatalytic activity of bimetallic Pd-AuNPs toward the oxygen reduction reaction (ORR) is conducted. In particular, a careful control of the amount of Au atoms introduced in the cluster and the evaluation of the optimum Pd:Au ratio for getting the maximum catalytic activity is performed for the first time. First, PdNPs are synthesized by alcohol reduction in the presence of polyvinylpyrrolidone, and gold atoms are selectively introduced on vertex or corner positions of the cluster in different amounts following a galvanic substitution procedure. Average elemental analysis done relying on EDX spectroscopy allows to evaluate the Pd:Au ratio in the Pd-AuNPs obtained. Lineal sweep voltammetry and chronoamperometry are used for the evaluation of the Pd-AuNPs electrocatalytic activity toward ORR at a neutral pH compared to PdNPs and AuNPs alone. Our results indicate that, the synergy between both metals is strongly enhanced when the amount of gold is controlled and occupies the more reactive positions of the cluster, reaching a maximum activity for the NPs containing a 30% of gold, while an excess of this metal leads to a decrease in such activity, as a shelter of the PdNPs is achieved. Chronoamperometric analysis allows the quantification of the optimal Pd-AuNPs at over 6 × 109 NPs/mL levels. Such optimal Pd-AuNPs were used as tags, taking advantage of the bio-functionalities of gold present in the cluster, in a proof-of-concept electrochemical immunosensor for the detection of hyaluronidase wound infection biomarker, using magnetic beads as platforms. Hyaluronidase was detected at levels as low as 50 ng/mL (0.02 U/mL; 437 U/mg) with good reproducibility (RSD below 8%) and selectivity (evaluated against bovine serum albumin, immunoglobulin G and lysozyme). The low matrix effects inherent to the use of magnetic bead platforms allowed us to discriminate between wound exudates with both sterile and infected ulcers without sample pre-treatment. This novel electrocatalytic immunoassay has the advantage, over common methods for NP tags electrochemical detection, of the signal generation in the same neutral medium where the immunoassay takes place (10 mM PBS pH 7.4), avoiding the use of additional and hazardous reagents, bringing it closer to their use as point-of-care devices. Overall, our findings may be of great interest not only for biosensing, but also for applications such as energy converting on fuel cells, in which the ORR has a pivotal role.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Infecção dos Ferimentos , Biomarcadores , Técnicas Eletroquímicas , Ouro , Humanos , Imunoensaio , Limite de Detecção , Paládio , Reprodutibilidade dos Testes
4.
Biosens Bioelectron ; 200: 113918, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34990957

RESUMO

Novel methods that enable facile, ultrasensitive and multiplexed detection of low molecular weight organic compounds such as metabolites, drugs, additives, and organic pollutants are valuable in biomedical research, clinical diagnosis, food safety and environmental monitoring. Here, we demonstrate a simple, rapid, and ultrasensitive method for detection and quantification of small molecules by implementing a competitive immunoassay with an ultrabright fluorescent nanolabel, plasmonic fluor. Plasmonic-fluor is comprised of a polymer-coated gold nanorod and bovine serum albumin conjugated with molecular fluorophores and biotin. The synthesis steps and fluorescence emission of plasmonic-fluor was characterized by UV-vis spectroscopy, transmission electron microscopy, and fluorescence microscopy. Plasmon-enhanced competitive assay can be completed within 20 min and exhibited more than 30-fold lower limit-of-detection for cortisol compared to conventional competitive ELISA. The plasmon-enhanced competitive immunoassay when implemented as partition-free digital assay enabled further improvement in sensitivity. Further, spatially multiplexed plasmon-enhanced competitive assay enabled the simultaneous detection of two analytes (cortisol and fluorescein). This simple, rapid, and ultrasensitive method can be broadly employed for multiplexed detection of various small molecules in research, in-field and clinical settings.


Assuntos
Técnicas Biossensoriais , Nanotubos , Bioensaio , Ouro , Imunoensaio
5.
Biosens Bioelectron ; 200: 113922, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34990959

RESUMO

Fast, affordable, portable, and sensitive technology to detect COVID-19 is critical to address the current outbreak. Here, we present a CRISPR/Cas12a-derived electrochemical aptasensor for cost-effective, fast, and ultrasensitive COVID-19 nucleocapsid protein (Np) detection. First, an electrochemical sensing interface was fabricated by immobilizing methylene blue labeled poly adenines DNA sequence (polyA-MB electrochemical reporter) on a gold electrode surface. Second, an arched probe was prepared via hybridization of Np aptamer and an activator strand. In the presence of COVID-19 Np, the activator strand could be released from the arched probe due to the specific interaction between the target and the aptamer, which then activated the trans-cleavage activity of the CRISPR/Cas12a system. Subsequently, the polyA-MB reporters were cleaved from the electrode surface, decreasing the current of differential pulse voltammetry (DPV) at a potential of -0.27 V(vs. Ag/AgCl). The CRISPR/Cas12a-derived electrochemical aptasensor shows a highly efficient performance for COVID-19 Np detection in 50 pg mL-1 to 100 ng mL-1 with a limit of detection (LOD) low to 16.5 pg mL-1. Notably, the whole process of one test can be completed within 30 min. Simultaneously, the aptasensor displays a high selectivity to other proteins. The further measurements demonstrate that the aptasensor is robust in a natural system for point-of-care testing, such as in tap water, milk, or serum. The aptasensor is universal and expandable and holds great potential in the COVID-19 early diagnosis, environmental surveillance, food security, and other aspects.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , COVID-19 , Sistemas CRISPR-Cas , Técnicas Eletroquímicas , Eletrodos , Ouro , Humanos , Limite de Detecção , Proteínas do Nucleocapsídeo , SARS-CoV-2
6.
Opt Lett ; 47(2): 373-376, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-35030609

RESUMO

Various nanostructures for single-molecule surface-enhanced Raman spectroscopy (SERS) have been fabricated through a random aggregation process using nanoparticles that can stochastically generate multiple hotspots in the laser spot. This leads to multiple molecule detection. In this study, a single gold nanoparticle (AuNP) dimer with a single hotspot was fabricated in a laser spot controlling the position and orientation on a silicon substrate using a nanotrench-guided self-assembly. The Raman peaks of deoxyribonucleic acid (DNA) were dynamically observed, indicating a single DNA oligomer detection composed of adenine, guanine, cytosine, phosphate, and deoxyribose.


Assuntos
Ouro , Nanopartículas Metálicas , DNA , Nanotecnologia , Análise Espectral Raman
7.
Anal Chim Acta ; 1191: 339306, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35033240

RESUMO

A novel graphene electrochemical transistor (GECT) sensor based on Au-poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (Au-PEDOT/rGO) nanocomposites functionalized the gate electrode and monolayer graphene as channel was proposed and constructed for the ultra-sensitive detection of acetaminophen (AP). Au-PEDOT/rGO nanocomposites were synthesized by a simple one-pot method to modify the gate electrode of GECT. With the high catalytic activity of Au nanoparticles, the good conductivity and stability of PEDOT, the large specific surface area and abundant adhesion sites of rGO, the sensitivity and stability of the device for AP detection could be effectively improved. The sensing mechanism of the device was that the electrochemical reactions of the AP on the surface of gate electrode causes the effective gate voltage on the GECT to change, thereby adjusting the carrier concentration and current of the graphene channel. Combined with the excellent catalytic properties of Au-PEDOT/rGO nanocomposites and the high carrier mobility of the graphene channel, the resulting device has remarkable sensing performance for AP, with a detection limit as low as 1 nM and a linear range from 1 nM to 8 mM. In addition, the device has good anti-interference ability and accuracy in the detection of AP in urine samples and tablets, which proved that it could be used to determine AP in human non-invasive and pharmaceutical products. The GECT sensor based on Au-PEDOT/rGO provides an efficient, sensitive and cost-effective sensing platform for AP detection, and is expected to realize in vitro diagnosis of diseases.


Assuntos
Grafite , Nanopartículas Metálicas , Nanocompostos , Acetaminofen , Compostos Bicíclicos Heterocíclicos com Pontes , Técnicas Eletroquímicas , Eletrodos , Ouro , Humanos , Polímeros
8.
Anal Chim Acta ; 1191: 339314, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35033249

RESUMO

In our research, label-free and surface-enhanced Raman dyes-free Raman spectroscopy which was used to detect carcinoembryonic antigen (CEA) according to poly adenine (Poly A)-regulated self-assembly methods was developed and studied. CEA induced partial hybridization of Ab-H2 and Ab-H1, and Ab-H1-CEA-Ab-H2 (a sandwich proximity CEA-DNA complex) was formed, which unfolded molecular beacon 1 (MB1) and modified the substrate. Subsequently, MB2-AuNPs were hybridized with MB1, and Ab-H1-CEA-Ab-H2 was released via toehold regulated displacements of DNA strands. Therefore, hybridization processes of MB2 and MB1 were induced and promoted by CEA-DNA complexes which worked as catalysts. The misplaced target then induced a next round of strand exchange, and the signals for determination of CEA were amplified by AuNPs absorbed on the substrate. It was indicated that the spectral characteristics of adenine at 736 cm-1 were consistent with the SERS spectrum of DNA. Adenine acted as an internal marker for label-free SERS detection of CEA. Moreover, satisfactory stability and reproducibility were found. Meanwhile, the antibody could specifically recognize the corresponding antigen. Since adenine was dominant in SERS spectra, which was also proximal to Au surface, the sensitivity of the novel method was high without modifications. The analytical performance of this method in determining serum CEA was satisfactory.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Antígeno Carcinoembrionário , DNA , Ouro , Limite de Detecção , Reprodutibilidade dos Testes , Análise Espectral Raman
9.
Anal Chim Acta ; 1191: 339346, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35033259

RESUMO

Electrochemiluminescence (ECL) is a powerful readout method for the development of (bio)sensors, whose performances depend on the electrode materials and the architecture of its surface. Herein, we demonstrate that the precise control of the sensing interface using the versatility of two-dimensional (2D) transition metal carbides (Ti3C2TX MXene) leads to the enhancement of the ECL signal. This electrode material, which exhibits remarkable structural and electrochemical properties was decorated by the in situ formation of gold nanoparticles (AuNPs) owing to the Ti reducibility. Then, a large amount of the luminophore, Ru(bpy)32+, was immobilized on Ti3C2TX MXene thanks to its unique negative charge and large specific surface area to obtain Ru-Ti3C2TX-AuNPs. The presented approach exploits the high catalytic activity and excellent conductivity of this 2D nanomaterial as illustrated by the enhanced ECL emission performance of the Ru-Ti3C2TX-AuNPs nanoprobes. Finally, DNA phosphorylated with polynucleotide kinase (PNK) was recognized efficiently by the chelation between Ti and phosphate group. A highly sensitive and selective ECL biosensor was developed for the detection of PNK and the screening of its inhibitors. A lower detection limit of 0.0002 U mL-1 and wide linear relationship ranged from 0.002 to 10 U mL-1 were obtained. Furthermore, the practicality of our method was tested in MCF-7 cell lysate, which opens enticing perspectives for future applications of Ti3C2TX materials in the ECL bioanalysis field.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Nanoestruturas , Técnicas Eletroquímicas , Ouro , Medições Luminescentes , Polinucleotídeo 5'-Hidroxiquinase , Titânio
10.
Anal Chim Acta ; 1191: 339312, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-35033271

RESUMO

A compact evanescent wave detection platform (EWDP) is developed for the detection of fluorescence gold nanoclusters. The EWDP employs a simple optical system and a Si-based photodetector SOP-1000 assembly to improve the optical efficiency and detection sensitivity. A microfluidic sample cell is also used to decrease the amount of analyte to 200 µL (The volume of sample cell is really about 30 µL). On this basis, we design a strategy for detecting dopamine (DA) based on the photoinduced electron transfer (PET) quenching mechanism. By introduction of tyrosinase (TYR) during the detection, the testing time is shortened to 1 min. The fluorescence emission signal decreased dramatically and the quenching ratio (F0-F)/F0 is linearly related to the concentration of DA in the range of 0.03-60 µM with a detection limit of 0.03 µM. Additionally, this detection platform has potential applications for DA fast detection in the microsamples.


Assuntos
Dopamina , Ouro , Transporte de Elétrons , Limite de Detecção , Monofenol Mono-Oxigenase/metabolismo , Espectrometria de Fluorescência
11.
Biosens Bioelectron ; 200: 113921, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34973567

RESUMO

The development of biosensors capable of averting biofouling and detecting biomarkers in complex biological media remains a challenge. Herein, an ultralow fouling and highly sensitive biosensor based on specifically designed antifouling peptides and a signal amplification strategy was designed for prostate specific antigen (PSA) detection in human serum. A low fouling layer of poly(ethylene glycol) (PEG) doped the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was electrodeposited on the electrode surface, followed by the immobilization of streptavidin and further attachment of biotin-labelled peptides. The peptide was designed to include PSA specific recognition domain (HSSKLQK) and antifouling domain (PPPPEKEKEKE), and the terminal of the peptide was functionalized with -SH group. DNA functionalized gold nanorods (DNA/AuNRs) were then attached to the electrode, and methylene blue (MB) molecules were adsorbed to the DNA to form the signal amplifier. In the presence of PSA, the peptide was specifically cleaved and resulted in the loss of AuNRs together with DNA and MB, and thus significant decrease of the current signal. The biosensor exhibited a low limit of detection (LOD) of 0.035 pg mL-1 (S/N = 3), with a wide linear range from 0.10 pg mL-1 to 10.0 ng mL-1, and it was able to detect PSA in real human serum owing to the presence of the antifouling peptides, indicating great potential of the constructed biosensor for practical application.


Assuntos
Incrustação Biológica , Técnicas Biossensoriais , Incrustação Biológica/prevenção & controle , Técnicas Eletroquímicas , Ouro , Humanos , Limite de Detecção , Masculino , Peptídeos , Antígeno Prostático Específico
12.
Food Chem ; 375: 131888, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34974348

RESUMO

In this study, an ultrasensitive monoclonal antibody (mAb) was produced and used to develop a gold nanoparticle-based lateral flow immunochromatographic (ICA) strip for screening of clomazone (CLO) in potato and pumpkin samples. With assayed by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method, the mAb belonging of IgG2 subclass showed a half-maximal inhibitory concentration (IC50) of 3.47 ng/mL and a linear range of detection of 0.43-28.09 ng/mL. A cross-reactivity test revealed that the mAb had good specificity for CLO. The strip assay had a visual limit of detection (LOD) of 5 µg/kg and a cut-off value of 50 µg/kg for CLO pumpkin samples (potato samples was 100 µg/kg) when evaluated with the naked eye. The results were consistent with ic-ELISA and high performance liquid chromatography tandem mass spectrometry (HPLC-MS). Thus, this ICA strip assay represents a potentially tool for on-site and rapid initial detection of CLO in potato and pumpkin samples.


Assuntos
Cucurbita , Nanopartículas Metálicas , Solanum tuberosum , Ensaio de Imunoadsorção Enzimática , Ouro , Coloide de Ouro , Imunoensaio , Isoxazóis , Limite de Detecção , Oxazolidinonas
13.
J Colloid Interface Sci ; 611: 695-705, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34979340

RESUMO

This paper describes the synthesis of highly branched gold nanoparticles (AuNPs) through a facile seeded growth approach using poly(allylamine hydrochloride) (PAH) as shape inducing agent. The obtained branched AuNPs present highly tunable optical properties in the Vis-NIR region from ca. 560 nm to 1260 nm. We controlled the morphology, and therefore the optical response, of the NPs by either changing the gold salt to seeds ratio or by fine-tuning the solution pH. We proposed that the formation of size-dependent PAH-AuCl4- aggregates as demonstrated by dynamic light scattering measurements, together with pH-dependent gold salt speciation might be responsible for the branched morphology. Advanced electron microscopy techniques demonstrated the polycrystalline nature of the AuNPs and facilitated a better understanding of branched morphology. Additionally, the refractive index sensitivity estimated by the inflection point of the Localized Surface Plasmon Resonance (LSPR) band can be controlled by tuning the nanoparticle branching. Furthermore, the versatility of the PAH chemistry allowed the easy functionalization of the synthesized NPs.


Assuntos
Ouro , Nanopartículas Metálicas , Poliaminas , Refratometria , Ressonância de Plasmônio de Superfície
14.
Biosens Bioelectron ; 200: 113861, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34986438

RESUMO

Typical protein biosensors employ chemical or genetic labeling of the protein, thus introducing an extraneous molecule to the wild-type parent protein, often changing the overall structure and properties of the protein. While these labeling methods have proven successful in many cases, they also have a series of disadvantages associated with their preparation and function. An alternative route for labeling proteins is the incorporation of unnatural amino acid (UAA) analogues, capable of acting as a label, into the structure of a protein. Such an approach, while changing the local microenvironment, poses less of a burden on the overall structure of the protein. L-DOPA is an analog of phenylalanine and contains a catechol moiety that participates in a quasi-reversible, two-electron redox process, thus making it suitable as an electrochemical label/reporter. The periplasmic glucose/galactose binding protein (GBP) was chosen to demonstrate this detection principle. Upon glucose binding, GBP undergoes a significant conformational change that is manifested as a change in the electrochemistry of L-DOPA. The electroactive GBP was immobilized onto gold nanoparticle-modified, polymerized caffeic acid, screen-printed carbon electrodes (GBP-LDOPA/AuNP/PCA/SPCE) for the purpose of direct measurement of glucose levels and serves as a proof-of-concept of the use of electrochemically-active unnatural amino acids as the label. The resulting reagentless GBP biosensors exhibited a highly selective and sensitive binding affinity for glucose in the micromolar range, laying the foundation for a new biosensing methodology based on global incorporation of an electroactive amino acid into the protein's primary sequence for highly selective electrochemical detection of compounds of interest.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Aminoácidos , Técnicas Eletroquímicas , Eletroquímica , Eletrodos , Ouro
15.
Food Chem ; 375: 131875, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34959139

RESUMO

A signal-enhanced LFIA based on tyramine (TYR)-induced AuNPs aggregation has been developed for the sensitive detection of danofloxacin (DAN). In the model, the hydroxyl radical produced by HRP catalyzing H2O2 can trigger the TYR-AuNPs to aggregate on the T or C line for enhancing the detection signal. The linear range of TYR-AuNPs LFIA was 0.25-5 ng mL-1 with the limit of detection (LOD) of 0.032 ng mL-1, and the LOD was 8-fold lower than that of the traditional AuNPs LFIA (0.26 ng mL-1). The TYR-AuNPs LFIA could be used with the naked eyes to qualitatively detect DAN with a cut-off limit of 2.5 ng mL-1, which was 4-fold lower than that of the traditional AuNPs LFIA (10 ng mL-1). The recoveries of TYR-AuNPs LFIA were 86.04-105.14% and 92.41-110.19%, with the coefficient of variation of 1.71-2.05% and 4.42-5.89% in chicken and pork, respectively.


Assuntos
Ouro , Nanopartículas Metálicas , Fluoroquinolonas , Peróxido de Hidrogênio , Imunoensaio , Limite de Detecção , Tiramina
16.
Cancer Lett ; 525: 1-8, 2022 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-34662546

RESUMO

The epidemiological correlation between obesity and cancer is well characterized, but the biological mechanisms which regulate tumor development and response to therapy in obese cancer patients remain unclear. The tumor microenvironment plays an important role in protecting cancer cells by altering the delivery of anticancer therapy to the tumor tissue, reducing the efficacy of treatment. Obese tumor microenvironment provides additional benefits to the survival of tumor cells against anticancer therapies by altering the extracellular matrix composition, angiogenesis processes and the immune cells profile. Nanotechnology, and in particular gold nanoparticles, are being researched as a theranostic strategy for cancer treatment due to their ability to sensitize cancer cells to radiation and photodynamic therapy, enhance delivery of drugs to tumor cells, and in diagnostic applications. Adipose tissue and the obese tumor microenvironment may alter the activity of nanotherapeutics. In this article, we reviewed the current state of our understanding about the mechanisms by which the obese tumor microenvironment may alter the delivery and efficacy of anti-cancer treatments, and why the use of gold nanoparticles may represent an interesting strategy for cancer treatment in the obesity setting.


Assuntos
Sistemas de Liberação de Medicamentos , Nanopartículas Metálicas/uso terapêutico , Neoplasias/tratamento farmacológico , Obesidade/tratamento farmacológico , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/patologia , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/genética , Ouro/química , Humanos , Nanopartículas Metálicas/química , Neoplasias/complicações , Neoplasias/genética , Neoplasias/patologia , Obesidade/complicações , Obesidade/genética , Obesidade/patologia , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/genética
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120701, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34896675

RESUMO

The existence and content of polycyclic aromatic hydrocarbons (PAHs) in the environment have gradually received attention because PAHs are widely detected in many sources. Therefore, an effective detection method for PAHs is necessary for further treatment. This study proposes a novel colorimetric detection method based on AuNPs to determine the contents of phenanthrene (Phe) and pyrene (Pyr). Trisodium citrate was used as a reducing agent to synthesize gold nanoparticles, and ammonium nitrate (NH4NO3) was added as a reactant to detect the analyte content. Some assay parameters, such as the concentration of NH4NO3 solution, the volume of NH4NO3 solution, the concentration of MES buffer solution, the volume of MES buffer solution, and the reaction time influenced the analyte detection ability of AuNPs and were optimized. The limits of detection for Phe and Pyr are 0.06 mg/L and 0.087 mg/L, respectively. In addition, the detection method has good selectivity and anti-interference ability for the target analytes. This colorimetric method was used to detect target analytes in real water (tap water and mineral water) with acceptable results.


Assuntos
Nanopartículas Metálicas , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Colorimetria , Ouro , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120707, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34902692

RESUMO

Nano-drug delivery systems may potentially overcome current challenges in the treatment of Parkinson's disease (PD) by enabling targeted delivery and more efficient blood-brain penetration ability. This study investigates novel gold nanoparticles (AuNPs) to be used as delivery systems for L-DOPA and dopamine by considering their binding capabilities in the presence and absence of a model protein, bovine serum albumin (BSA). Four different AuNPs were prepared by surface functionalization with polyethylene glycol (PEG), 1-adamantylamine (Ad), 1-adamantylglycine (AdGly), and peptidoglycan monomer (PGM). Fluorescence and UV-Vis measurements demonstrated the strongest binding affinity and L-DOPA/dopamine loading efficiency for PGM-functionalized AuNPs with negligible impact of the serum protein presence. Thermodynamic analysis revealed a spontaneous binding process between L-DOPA or dopamine and AuNPs that predominantly occurred through van der Waals interactions/hydrogen bonds or electrostatic interactions. These results represent PGM-functionalized AuNPs as the most efficient at L-DOPA and dopamine binding with a potential to become a drug-delivery system for neurodegenerative diseases. Detailed investigation of L-DOPA/dopamine interactions with different AuNPs was described here for the first time. Moreover, this study highlights a cost- and time-effective methodology for evaluating drug binding to nanomaterials.


Assuntos
Nanopartículas Metálicas , Doença de Parkinson , Dopamina , Sistemas de Liberação de Medicamentos , Ouro , Humanos , Levodopa , Doença de Parkinson/tratamento farmacológico
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120682, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34906842

RESUMO

The isomers cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) can both be extracted from cannabis. We use density functional theory to study the Raman activity spectra, frontier molecular orbitals, and molecular electrostatic potentials of CBD, THC, and their respective gold complexes. A "selectivity enhancement" phenomenon for the spectral peaks at frequencies of 1144 cm-1 and 1553 cm-1 in the Raman spectrum of the CBD-Aun complex, and at frequencies of 865 cm-1, 1335 cm-1, and 1553 cm-1 in the Raman spectrum of the THC-Aun complex, was observed and explained. The frontier molecular orbital energy gaps of CBD and THC are 5.4085 eV and 5.4461 eV, respectively, indicating that CBD is more likely to react than THC. The CBD/THC-Au complexes had the strongest chemical activities and greater charge transfer effects with an Au3 cluster. The most electronegative sites of CBD and THC were found from molecular electrostatic potential (MEP) mapping. It is assumed that these sites are the adsorption sites of the CBD/THC molecules and gold surface. The MEP of the CBD/THC complexes also demonstrates the charge transfer effect between CBD/THC and Au. Both the "selectivity" phenomenon in the Raman activity spectra of the complex and the above assumption are explained by a surface selection rule. The conformation of the CBD/THC molecules on the gold surface are determined, showing that CBD is adsorbed vertically through the resorcinol structure while THC is adsorbed vertically through the tetrahydropyran and benzene ring.


Assuntos
Canabidiol , Nanopartículas Metálicas , Teoria da Densidade Funcional , Dronabinol , Ouro , Análise Espectral Raman
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120706, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34915228

RESUMO

Cobalt as a transition metal ion is a biologically essential trace element, and plays an important role in various biological systems. The silicon nanoparticles (SiNPs) / gold nanoparticles (AuNPs) composite as a simple and efficient fluorescent probe was developed to detect Co2+ and vitamin B12 (VB12) based on the selective aggregation and inner filter effect (IFE). The green-emitting SiNPs were synthesized by one-pot hydrothermal method, and the AuNPs were synthesized and modified with thioglycolic acid and cetyltrimethylammonium bromide. The fluorescent probe was fabricated by simple mixing the SiNPs and AuNPs together. In the presence of Co2+/VB12, AuNPs are selectively aggregated, which results in the enhancement of the local surface plasmon resonance absorption centered at 520 nm and the green fluorescence of SiNPs is significantly quenched via IFE. The fluorescence quenching efficiency of the probe is linearly proportional to the concentration of Co2+ in the range of 0.1-80 µM with a low detection limit of 60 nM, which is far lower than the guideline value of Co2+ in drinking water (1.7 µM). For vitamin B12 (VB12), its linear relationship is in the range of 0.1-100 µM, and the limit of detection is 69 nM. Furthermore, the proposed method shows good selectivity for the detection of Co2+ and VB12, and does not need sophisticated pretreatment, only through simple filter. It has been applied in actual environmental water samples and drug tablets with satisfactory results.


Assuntos
Nanopartículas Metálicas , Pontos Quânticos , Fluorescência , Corantes Fluorescentes , Ouro , Limite de Detecção , Silício , Vitamina B 12 , Vitaminas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA