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1.
Transl Vis Sci Technol ; 13(3): 4, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38466299

RESUMO

Purpose: The purpose of this study was to search for contaminants in silicone oil tamponades removed from eyes treated for retinal detachment, and to correlate chemical results with some clinical/functional parameters of the considered eyes. Methods: We examined a sequential cohort of eyes grouped according to the tamponade received: (1) Siluron2000 (S2), (2) RS-OIL ECS5000 (S5), and (3) Densiron Xtra (DX). Samples were collected at the beginning of the scheduled removal and analyzed by untargeted headspace gas-chromatography mass spectrometry (HS-GC-MS). Visual acuity and optic coherence tomography assessments were obtained before and after the tamponade removal. Results: Forty-one samples were analyzed: 22 belonging to the DX group, 13 to the S2 group, and 6 to the S5 group. For each group, a mixture of uninjected commercial preparation was analyzed as the reference. Different siloxanes and fluorinated compounds including perfluorodecalin (PFCL) were the most prevalent chemicals, found in 55% to 100% of the intraocular samples of the 3 groups. Some siloxanes were present also in the control matrices, whereas PFCL was only in the extracted tamponades. In the DX group, the concentration of hexamethylcyclotrisiloxane showed an inverse correlation trend with the duration of its permanence inside the eye (P = 0.054). Different alkanes, propanol, and acetaldehyde were identified only in the control matrices. Conclusions: Several contaminants including siloxanes were identified in the intraocular samples and in the control matrices. A time-related ocular uptake of some of these is conceivable. PFCL was also highly present but only in intraocular samples. Translational Relevance: After intraocular permanence silicone oils (SOs) have various unlabeled contaminants with some relevant differences with the commercial formulation chemical profile.


Assuntos
Fluorocarbonos , Descolamento Retiniano , Humanos , Descolamento Retiniano/cirurgia , Óleos de Silicone , Siloxanas , Olho
2.
Anal Chem ; 96(6): 2719-2726, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38294352

RESUMO

Aptamers are recognition elements increasingly used for the development of biosensing strategies, especially in the detection of proteins or small molecule targets. Lysozyme, which is recognized as an important biomarker for various diseases and a major allergenic protein found in egg whites, is one of the main analytical targets of aptamer-based biosensors. However, since aptamer-based strategies can be prone to artifacts and data misinterpretation, rigorous strategies for multifaceted characterization of the aptamer-target interaction are needed. In this work, a multitechnique approach has been devised to get further insights into the binding performance of the anti-lysozyme DNA aptamers commonly used in the literature. To study molecular interactions between lysozyme and different anti-lysozyme DNA aptamers, measurements based on a magneto-electrochemical apta-assay, circular dichroism spectroscopy, fluorescence spectroscopy, and asymmetrical flow field-flow fractionation were performed. The reliability and versatility of the approach were proved by investigating a SELEX-selected RNA aptamer reported in the literature, that acts as a positive control. The results confirmed that an interaction in the low micromolar range is present in the investigated binding buffers, and the binding is not associated with a conformational change of either the protein or the DNA aptamer. The similar behavior of the anti-lysozyme DNA aptamers compared to that of randomized sequences and polythymine, used as negative controls, showed nonsequence-specific interactions. This study demonstrates that severe testing of aptamers resulting from SELEX selection is the unique way to push these biorecognition elements toward reliable and reproducible results in the analytical field.


Assuntos
Aptâmeros de Nucleotídeos , Aptâmeros de Nucleotídeos/química , Muramidase , Reprodutibilidade dos Testes , Técnica de Seleção de Aptâmeros/métodos , Anticorpos Antinucleares
3.
Sci Total Environ ; 917: 170168, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38244628

RESUMO

The European Union is among the top wheat producers in the world, but its productivity relies on adequate soil fertilisation. Biofertilisers, either alone or in combination with biochar, can be a preferable alternative to chemical fertilisers. However, the addition of biofertilisers, specifically plant growth promoting microbes (PGPM), could modify grain composition, and/or deteriorate the soil composition. In this study, the two wheat cultivars Triticum aestivum (Bramante) and T. durum (Svevo) were cultivated in open fields for two consecutive years in the presence of a commercial PGPM mix supplied alone or in combination with biochar. An in-depth analysis was conducted by collecting physiological and agronomic data throughout the growth period. The effects of PGPM and biochar were investigated in detail; specifically, soil chemistry and rhizosphere microbial composition were characterized, along with the treatment effects on seed storage proteins. The results demonstrated that the addition of commercial microbial consortia and biochar, alone or in combination, did not modify the rhizospheric microbial community; however, it increased grain yield, especially in the cultivar Svevo (increase of 6.8 %-13.6 %), even though the factors driving the most variations were associated with both climate and cultivar. The total gluten content of the flours was not affected, whereas the main effect of the treatments was a variation in gliadins and low-molecular-weight-glutenin subunits in both cultivars when treated with PGPM and biochar. This suggested improved grain quality, especially regarding the viscoelastic properties of the dough, when the filling period occurred in a dry climate. The results indicate that the application of biofertilisers and biochar may aid the effective management of sustainable wheat cultivation, to support environmental health without altering the biodiversity of the resident microbiome.


Assuntos
Consórcios Microbianos , Triticum , Grão Comestível , Carvão Vegetal/farmacologia , Solo/química
4.
J Agric Food Chem ; 71(41): 15407-15416, 2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37796632

RESUMO

Sustainable agriculture aims at achieving a healthy food production while reducing the use of fertilizers and greenhouse gas emissions using biostimulants and soil amendments. Untargeted metabolomics by ultra-high performance liquid chromatography-ion mobility-high-resolution mass spectrometry, operating in a high-definition MSE mode, was applied to investigate the metabolome of durum wheat in response to sustainable treatments, i.e., the addition of biochar, commercial plant growth promoting microbes, and their combination. Partial least squares-discriminant analysis provided a good discrimination among treatments with sensitivity, specificity, and a non-error rate close to 1. A total of 88 and 45 discriminant compounds having biological, nutritional, and technological implications were tentatively identified in samples grown in 2020 and 2021. The addition of biochar-biostimulants produced the highest up-regulation of lipids and flavonoids, with the glycolipid desaturation being the most impacted pathway, whereas carbohydrates were mostly down-regulated. The findings achieved suggest the safe use of the combined biochar-biostimulant treatment for sustainable wheat cultivation.


Assuntos
Metabolômica , Triticum , Cromatografia Líquida de Alta Pressão/métodos , Metabolômica/métodos , Espectrometria de Massas/métodos
5.
Sci Rep ; 13(1): 8967, 2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-37268814

RESUMO

Dental calculus is a valuable resource for the reconstruction of dietary habits and oral microbiome of past populations. In 2020 the remains of Duke Alessandro Farnese and his wife Maria D'Aviz were exhumed to get novel insights into the causes of death. This study aimed to investigate the dental calculus metabolome of the noble couple by untargeted metabolomics. The pulverized samples were decalcified in a water-formic acid mixture, extracted using methanol/acetonitrile and analyzed by ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) using a reversed-phase separation followed by electrospray ionization and full scan in positive and negative ion mode. Waters Synapt-G2-Si High-Definition hybrid quadrupole time-of-flight mass spectrometer was used. Significant features were then identified using MSE acquisition mode, recording information on exact mass precursor and fragment ions within the same run. This approach, together with data pre-treatment and multivariate statistical analysis allowed for the identification of compounds able to differentiate between the investigated samples. More than 200 metabolites were identified, being fatty acids, alcohols, aldehydes, phosphatidylcholines, phosphatidylglycerols, ceramides and phosphatidylserines the most abundant classes. Metabolites deriving from food, bacteria and fungi were also determined, providing information on the habits and oral health status of the couple.


Assuntos
Cálculos Dentários , Metabolômica , Humanos , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas , Metabolômica/métodos , Metaboloma
6.
Sci Rep ; 13(1): 6116, 2023 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-37059833

RESUMO

Mass spectrometry (MS)-based proteomics has recently attracted the attention from forensic pathologists. This work is the first report of the development of a shotgun bottom-up proteomic approach based on rapid protein extraction and nano-liquid chromatography/high-resolution mass spectrometry applied to full-thickness human skin for the differential analysis of normal and ecchymotic tissues to identify new biomarkers for bruise characterization and dating. We identified around 2000 proteins from each pooled extract. The method showed excellent precision on independent replicates, with Pearson correlation coefficients always higher than 95%. Glycophorin A, a known biomarker of vital wounds from immunochemical studies, was identified only in ecchymotic tissues, as confirmed by Western blotting analysis. This finding suggests that this protein can be used as a MS-detectable biomarker of wound vitality. By focusing on skin samples from individuals with known wound dating, besides Glycophorin A, other proteins differentially expressed in ecchymotic samples and dependant on wound age were identified, although further analysis on larger datasets are needed to validate these findings. This study paves the way for an in-depth investigation of the potential of MS-based techniques for wound examination in forensic pathology, overcoming the limitations of immunochemical assays.


Assuntos
Glicoforinas , Espectrometria de Massas em Tandem , Humanos , Espectrometria de Massas em Tandem/métodos , Proteômica/métodos , Patologia Legal , Proteínas/metabolismo , Biomarcadores
7.
Curr Oncol ; 30(2): 1332-1353, 2023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-36826064

RESUMO

BACKGROUND: The words "hope" and "cure" were used in a greater number of articles and sentences in narrative and editorial papers than in primary research. Despite concomitant improvements in cancer outcomes, the related reluctance to use these terms in more scientifically oriented original reports may reflect a bias worthy of future exploration. This study aims to survey a group of physicians and cancer patients regarding their perception and use of the word cure. MATERIALS AND METHOD: An anonymous online and print survey was conducted to explore Italian clinicians' (the sample includes medical oncologists, radiotherapists, and oncological surgeons) and cancer patients' approach to the perception and use of the word "cure" in cancer care. The participants received an email informing them of the study's purpose and were invited to participate in the survey via a linked form. A portion, two-thirds, of questionnaires were also administered to patients in the traditional paper form. RESULTS: The survey was completed by 224 clinicians (54 oncologists, 78 radiotherapists, and 92 cancer surgeons) and 249 patients. The results indicate a favourable attitude for patients in favour of a new language ("cured" vs. "complete remission") of the disease experience. CONCLUSIONS: The use of the word cured is substantially accepted and equally shared by doctors and patients. Its use can facilitate the elimination of metaphoric implications and toxic cancer-related connotations registered in all cultures that discourage patients from viewing cancer as a disease with varied outcomes, including cure.


Assuntos
Neoplasias , Médicos , Humanos , Inquéritos e Questionários , Atitude , Idioma
8.
Anal Bioanal Chem ; 415(1): 119-135, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36367573

RESUMO

Traditional techniques for food analysis are based on off-line laboratory methods that are expensive and time-consuming and often require qualified personnel. Despite the high standards of accuracy and metrological traceability, these well-established methods do not facilitate real-time process monitoring and timely on-site decision-making as required for food safety and quality control. The future of food testing includes rapid, cost-effective, portable, and simple methods for both qualitative screening and quantification of food contaminants, as well as continuous, real-time measurement in production lines. Process automatization through process analytical technologies (PAT) is an increasing trend in the food industry as a way to achieve improved product quality, safety, and consistency, reduced production cycle times, minimal product waste or reworks, and the possibility for real-time product release. Novel methods of analysis for point-of-need (PON) screening could greatly improve food testing by allowing non-experts, such as consumers, to test in situ food products using portable instruments, smartphones, or even visual naked-eye inspections, or farmers and small producers to monitor products in the field. This requires the attention of the research community and devices manufacturers to ensure reliability of measurement results from PAT strategy and PON tests through the demonstration and critical evaluation of performance characteristics. The fitness for purpose of methods in real-life conditions is a priority that should not be overlooked in order to maintain an effective and harmonized food safety policy.


Assuntos
Inocuidade dos Alimentos , Reprodutibilidade dos Testes , Inocuidade dos Alimentos/métodos , Controle de Qualidade , Padrões de Referência
9.
Molecules ; 27(23)2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36500684

RESUMO

Methyl farnesoate (MF), a juvenile hormone, can influence phenotypic traits and stimulates male production in daphnids. MF is produced endogenously in response to stressful conditions, but it is not known whether this hormone can also be released into the environment to mediate stress signaling. In the present study, for the first time, a reliable solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method was developed and validated for the ultra-trace analysis of MF released in growth medium by Daphnia pulex maintained in presence of crowding w/o MK801, a putative upstream inhibitor of MF endogenous production. Two different clonal lineages, I and S clones, which differ in the sensitivity to the stimuli leading to male production, were also compared. A detection limit of 1.3 ng/L was achieved, along with good precision and trueness, thus enabling the quantitation of MF at ultra-trace level. The achieved results demonstrated the release of MF by both clones at the 20 ng/L level in control conditions, whereas a significant decrease in the presence of crowding was assessed. As expected, a further reduction was obtained in the presence of MK801. These findings strengthen the link between environmental stimuli and the MF signaling pathway. Daphnia pulex, by releasing the juvenile hormone MF in the medium, could regulate population dynamics by means of an autoregulatory feedback loop that controls the intra- and extra-individual-level release of MF produced by endogenous biosynthesis.


Assuntos
Daphnia , Ácidos Graxos Insaturados , Animais , Masculino , Daphnia/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Ácidos Graxos Insaturados/farmacologia , Hormônios Juvenis , Microextração em Fase Sólida/métodos
10.
Sensors (Basel) ; 22(14)2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35891142

RESUMO

Innovative and highly performing smart voltammetric immunosensors for rapid and effective serological tests aimed at the determination of SARS-CoV-2 antibodies were developed and validated in human serum matrix. Two immunosensors were developed for the determination of immunoglobulins directed against either the nucleocapsid or the spike viral antigen proteins. The immunosensors were realized using disposable screen-printed electrodes modified with nanostructured materials for the immobilization of the antigens. Fast quantitative detection was achieved, with analysis duration being around 1 h. Signal readout was carried out through a smart, compact and battery-powered potentiostat, based on a Wi-Fi protocol and devised for the Internet of Things (IoT) paradigm. This device is used for the acquisition, storage and sharing of clinical data. Outstanding immunosensors' sensitivity, specificity and accuracy (100%) were assessed, according to the diagnostic guidelines for epidemiological data. The overall performance of the sensing devices, combined with the portability of the IoT-based device, enables their suitability as a high-throughput diagnostic tool. Both of the immunosensors were validated using clinical human serum specimens from SARS-CoV-2 infected patients, provided by IRCCS Ospedale San Raffaele.


Assuntos
Técnicas Biossensoriais , COVID-19 , Vacinas , Anticorpos Antivirais , Técnicas Biossensoriais/métodos , COVID-19/diagnóstico , Humanos , Imunoensaio , Sistemas Automatizados de Assistência Junto ao Leito , SARS-CoV-2 , Sensibilidade e Especificidade , Testes Sorológicos
11.
Biosensors (Basel) ; 12(6)2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35735573

RESUMO

An IoT-WiFi smart and portable electrochemical immunosensor for the quantification of SARS-CoV-2 spike protein was developed with integrated machine learning features. The immunoenzymatic sensor is based on the immobilization of monoclonal antibodies directed at the SARS-CoV-2 S1 subunit on Screen-Printed Electrodes functionalized with gold nanoparticles. The analytical protocol involves a single-step sample incubation. Immunosensor performance was validated in a viral transfer medium which is commonly used for the desorption of nasopharyngeal swabs. Remarkable specificity of the response was demonstrated by testing H1N1 Hemagglutinin from swine-origin influenza A virus and Spike Protein S1 from Middle East respiratory syndrome coronavirus. Machine learning was successfully used for data processing and analysis. Different support vector machine classifiers were evaluated, proving that algorithms affect the classifier accuracy. The test accuracy of the best classification model in terms of true positive/true negative sample classification was 97.3%. In addition, the ML algorithm can be easily integrated into cloud-based portable Wi-Fi devices. Finally, the immunosensor was successfully tested using a third generation replicating incompetent lentiviral vector pseudotyped with SARS-CoV-2 spike glycoprotein, thus proving the applicability of the immunosensor to whole virus detection.


Assuntos
Técnicas Biossensoriais , COVID-19 , Vírus da Influenza A Subtipo H1N1 , Nanopartículas Metálicas , COVID-19/diagnóstico , Ouro , Humanos , Imunoensaio/métodos , Aprendizado de Máquina , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/análise
12.
Food Chem ; 388: 132951, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35447585

RESUMO

The present review throws a spotlight on new and emerging food safety concerns in view of a well-established food allergen risk arising from global socio-economic changes, international trade, circular economy, environmental sustainability, and upcycling. Food culture globalization needs harmonization of regulations, technical specifications, and reference materials towards mutually recognised results. In parallel, routine laboratories require high-throughput reliable analytical strategies, even in-situ testing devices, to test both food products and food contact surfaces for residual allergens. Finally, the currently neglected safety issues associated to possible allergen exposure due to the newly proposed bio- and plant-based sustainable food contact materials require an in-depth investigation.


Assuntos
Alérgenos , Hipersensibilidade Alimentar , Comércio , Alimentos , Humanos , Internacionalidade
13.
ACS Appl Mater Interfaces ; 14(17): 19204-19211, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35446532

RESUMO

Efficient and timely testing has taken center stage in the management, control, and monitoring of the current COVID-19 pandemic. Simple, rapid, cost-effective diagnostics are needed that can complement current polymerase chain reaction-based methods and lateral flow immunoassays. Here, we report the development of an electrochemical sensing platform based on single-walled carbon nanotube screen-printed electrodes (SWCNT-SPEs) functionalized with a redox-tagged DNA aptamer that specifically binds to the receptor binding domain of the SARS-CoV-2 spike protein S1 subunit. Single-step, reagentless detection of the S1 protein is achieved through a binding-induced, concentration-dependent folding of the DNA aptamer that reduces the efficiency of the electron transfer process between the redox tag and the electrode surface and causes a suppression of the resulting amperometric signal. This aptasensor is specific for the target S1 protein with a dissociation constant (KD) value of 43 ± 4 nM and a limit of detection of 7 nM. We demonstrate that the target S1 protein can be detected both in a buffer solution and in an artificial viral transport medium widely used for the collection of nasopharyngeal swabs, and that no cross-reactivity is observed in the presence of different, non-target viral proteins. We expect that this SWCNT-SPE-based format of electrochemical aptasensor will prove useful for the detection of other protein targets for which nucleic acid aptamer ligands are made available.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , COVID-19 , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , COVID-19/diagnóstico , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Limite de Detecção , Pandemias , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus
14.
J Chromatogr A ; 1671: 463010, 2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35405408

RESUMO

A magnetic hybrid material based on the use of the mixed-ligand Metal-Organic Framework (MOF) PUM198 is proposed for the magnetic dispersive micro solid-phase extraction (MD-µSPE) of the 16 polycyclic aromatic hydrocarbons (PAHs) included in the US-EPA priority pollutants list. PUM198 is a thermally robust MOF characterized by a doubly interpenetrated microporous framework in which Zn2+ ions and carboxylate groups define 2D planes that are pillared by a bis-pyridine-bis amide ligand containing a biphenyl scaffold. PUM198 revealed to be ideal to adsorb PAHs efficiently through non-covalent interactions. A Plackett-Burman Design followed by a Central Composite Design and the multicriteria method of the desirability functions were applied to find the optimal conditions for the extraction of the investigated PAHs, resulting in a reduced solvent consumption, i.e., 50 µL of solvent per extraction for 5 mL of sample, approximatively 3-20 times lower than those reported in previous studies, thus satisfying the principles of green analytical chemistry. Method validation proved the reliability of the method for the determination of PAHs at trace level, obtaining detection limits in the 6.7-27 ng/L range, good precision with RSDs% lower than 19% and recovery rates in the 99 (±13)-126 (±8)% range near the quantitation limit. Finally, the applicability of the method was demonstrated by analyzing underground water samples taken from contaminated sites.


Assuntos
Estruturas Metalorgânicas , Hidrocarbonetos Policíclicos Aromáticos , Compostos Policíclicos , Poluentes Químicos da Água , Cromatografia Gasosa-Espectrometria de Massas , Ligantes , Limite de Detecção , Fenômenos Magnéticos , Hidrocarbonetos Policíclicos Aromáticos/análise , Compostos Policíclicos/análise , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Solventes/química , Água , Poluentes Químicos da Água/análise
15.
Anal Chem ; 94(12): 5075-5083, 2022 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-35303407

RESUMO

Carbon nanotube (CNT)-based electrodes are cheap, highly performing, and robust platforms for the fabrication of electrochemical sensors. Engineering programmable DNA nanotechnologies on the CNT surface can support the construction of new electrochemical DNA sensors providing an amperometric output in response to biomolecular recognition. This is a significant challenge, since it requires gaining control of specific hybridization processes and functional DNA systems at the interface, while limiting DNA physisorption on the electrode surface, which contributes to nonspecific signal. In this study, we provide design rules to program dynamic DNA structures at the surface of single-walled carbon nanotubes electrodes, showing that specific DNA interactions can be monitored through measurement of the current signal provided by redox-tagged DNA strands. We propose the use of pyrene as a backfilling agent to reduce nonspecific adsorption of reporter DNA strands and demonstrate the controlled formation of DNA duplexes on the electrode surface, which we then apply in the design and conduction of programmable DNA strand displacement reactions. Expanding on this aspect, we report the development of novel amperometric hybridization platforms based on artificial DNA structures templated by the small molecule melamine. These platforms enable dynamic strand exchange reactions orthogonal to conventional toehold-mediated strand displacement and may support new strategies in electrochemical sensing of biomolecular targets, combining the physicochemical properties of nanostructured carbon-based materials with programmable nucleic acid hybridization.


Assuntos
Nanotubos de Carbono , DNA/química , Eletrodos , Nanotecnologia , Nanotubos de Carbono/química , Hibridização de Ácido Nucleico
16.
Anal Bioanal Chem ; 414(18): 5519-5527, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35182166

RESUMO

Aptamers are biomimetic receptors that are increasingly exploited for the development of optical and electrochemical aptasensors. They are selected in vitro by the SELEX (Systematic Evolution of Ligands by Exponential Enrichment) procedure, but although they are promising recognition elements, for their reliable applicability for analytical purposes, one cannot ignore sample components that cause matrix effects. This particularly applies when different SELEX-selected aptamers and related truncated sequences are available for a certain target, and the choice of the aptamer should be driven by the specific downstream application. In this context, the present work aimed at investigating the potentialities of asymmetrical flow field-flow fractionation (AF4) with UV detection for the development of a screening method of a large number of anti-lysozyme aptamers towards lysozyme, including randomized sequences and an interfering agent (serum albumin). The possibility to work in native conditions and selectively monitor the evolution of untagged aptamer signal as a result of aptamer-protein binding makes the devised method effective as a strategy for shortlisting the most promising aptamers both in terms of affinity and in terms of selectivity, to support subsequent development of aptamer-based analytical devices.


Assuntos
Aptâmeros de Nucleotídeos , Técnica de Seleção de Aptâmeros , Aptâmeros de Nucleotídeos/metabolismo , Ligantes , Ligação Proteica , Técnica de Seleção de Aptâmeros/métodos
17.
Anal Bioanal Chem ; 414(1): 63-74, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34245326

RESUMO

An outlook on the current status of different strategies for magnetic micro- and nanosized bead functionalization with aptamers as prominent bioreceptors is given with a focus on electrochemical and optical apta-assays, as well as on aptamer-modified magnetic bead-based miniaturized extraction techniques in food control. Critical aspects that affect interaction of aptamers with target molecules, as well as the possible side effects caused by aptamer interaction with other molecules due to non-specific binding, are discussed. Challenges concerning the real potential and limitations of aptamers as bioreceptors when facing analytical problems in food control are addressed.


Assuntos
Aptâmeros de Nucleotídeos/química , Análise de Alimentos/métodos , Fenômenos Magnéticos , Microesferas , Técnicas Biossensoriais , Microbiologia de Alimentos , Ouro , Nanocompostos
18.
Chemosphere ; 282: 131082, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470154

RESUMO

For the first time an eco-friendly method involving microextraction by packed sorbent (MEPS) coupled to gas chromatography-mass spectrometry (GC-MS) was developed for the determination of the 16 US-EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) as indicators of anthropogenic contamination in snow samples collected in polar regions. MEPS was carried out by using C8 sorbent material packed in a barrel insert and needle (BIN) and integrated in the eVol® semi-automatic device. For optimization purposes a Face Centred Design and the multicriteria method of the desirability functions were performed to investigate the effect of some parameters affecting the MEPS extraction efficiency, i.e. the number of loading cycles and the number of elution cycles. The developed MEPS-GC-MS method proved to be suitable for PAHs analysis at ultra-trace level by extracting small sample volumes achieving detection limits for 16 PAHs in the 0.3-5 ng L-1 range, repeatability and intermediate precision below 11% and 15%, respectively, and good recovery rates in the 77.6 (±0.1)-120.8 (±0.1)% range for spiked blank snow samples. Enrichment factors in the 64 (±7)-129 (±18) range were calculated. Finally, the proposed method was successfully applied to the determination of PAHs in surface snow samples collected in 2020-2021 from four locations of Northern Victoria Land, Antarctica. Local emission sources such as ships and research stations were found to influence PAHs concentrations in the surface snow.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Regiões Antárticas , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Hidrocarbonetos Policíclicos Aromáticos/análise , Neve , Microextração em Fase Sólida , Poluentes Químicos da Água/análise
19.
J Chromatogr A ; 1648: 462209, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34000595

RESUMO

Two commercial stationary phases allowing both reversed phase mechanism and anion-exchange with different selectivity, i.e. CSH C18 and Atlantis PREMIER BEH C18 AX, were tested for the separation of a complex mixture of 21 fatty acids (FAs) encompassing saturated medium-, long- and very long chain FAs, unsaturated long and very long chain FAs, cis/trans isomers, and isomers of odd- and branched-chain FAs. For this purpose, the role of surface area of stationary phase and the effect of pH of the mobile phase on the retention of the analytes were investigated. Separation was performed by ultra-high-performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC-HRMS). BEH C18 AX was shown to be more versatile and to offer superior retention of these analytes to CSH C18 owing to a higher surface area and anion-exchange capacity up to pH 8.5. The UHPLC system allows shortening analysis time, the chromatographic analysis being accomplished in about 5 min, affording a high throughput of samples without the need for derivatization or ion-pairing reagents compared to techniques based upon gas chromatography approaches or LC. Finally, the application of the BEH C18 AX column using UHPLC-HRMS was demonstrated for the separation and unambiguous identification of FAs of nutritional interest in a dietary supplement sample.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia por Troca Iônica/métodos , Ácidos Graxos não Esterificados/análise , Espectrometria de Massas/métodos , Ânions , Isomerismo
20.
Anal Chim Acta ; 1153: 338297, 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33714443

RESUMO

A novel enzyme-labelled voltammetric magnetogenoassay for DNA sensing based on the use of carboxyl-surface coated magnetic microbeads functionalized with PNA probes and subsequent read-out on screen-printed electrode (SPE) substrates was developed. The assay was validated for determination of non-amplified genomic DNA from genetically modified Roundup Ready soy. Outstanding performance with respect to other genoassays requiring preliminary amplification of target DNA via PCR was demonstrated. The analytical performance was also improved compared to previous methods based on the immobilization of the same PNA probes on SPE substrates, since the method was found capable of achieving LOD and LOQ of 415 fM and 995 fM, respectively. The ability of the magnetogenoassay to detect the presence of Roundup Ready soy DNA sequence was tested on genomic DNA extract from European Reference Material soy flours, demonstrating the capability of the method to match the European Union regulation for labelling of food containing a percentage of GM products greater than 0,9%.


Assuntos
Fenômenos Magnéticos , DNA de Plantas , Microesferas , Plantas Geneticamente Modificadas/genética , /genética
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