21 documents found, page 1 of 3
In vitro selection of DNA aptamers against staphylococcal enterotoxin A
Oliveira, Ricardo; Pinho, Eva; Barros, Maria Margarida; Azevedo, Nuno Filipe; Almeida, Carina Manuela FernandesStaphylococcal enterotoxin A (SEA) is the most frequently reported in staphylococcal food poisoning (SFP) outbreaks. Aptamers are single-stranded nucleic acids that are seen as promising alternatives to antibodies in several areas, including diagnostics. In this work, systematic evolution of ligands by exponential enrichment (SELEX) was used to select DNA aptamers against SEA. The SELEX protocol employed magnet...
The potential of tailed amplicons for SARS-CoV-2 detection in nucleic acid late...
Vindeirinho, João M.; Oliveira, Ricardo; Pinho, Eva; Guiomar, Raquel; Azevedo, Nuno F.; Almeida, Carina Manuela FernandesNucleic Acid Lateral Flow Assays (NALFAs) are a promising solution for the point-of-care detection of viruses like SARS-CoV-2. However, they show some drawbacks, such as the great dependency on the use of antibodies and the need for post-amplification protocols that enable the preparation of amplicons for effective readings, as well as low sensitivity. Here, we developed amplicons of a specific SARS-CoV-2 gene ...
Development of an aptamer-based biosensor for the detection of food toxins
Oliveira, Ricardo; Pinho, Eva; Azevedo, Nuno Filipe; Almeida, CarinaAccording to the last EFSA/ECDC report, bacterial toxins are the second leading causative agent (17.0%) of foodborne outbreaks in Europe [1]. Aptasensors, as biosensors that use aptamers are called, are seen as a simple, rapid and cost-effective assay format with high suitability for point-of-care testing, allowing a sensitive and mostly qualitative detection of analytes [2]. In this work, DNA aptamers previous...
SARS-CoV-2 diagnostics based on nucleic acids amplification: from fundamental c...
Vindeirinho, João M.; Pinho, Eva; Azevedo, Nuno F.; Almeida, Carina Manuela FernandesCOVID-19 pandemic ignited the development of countless molecular methods for the diagnosis of SARS-CoV-2 based either on nucleic acid, or protein analysis, with the first establishing as the most used for routine diagnosis. The methods trusted for day to day analysis of nucleic acids rely on amplification, in order to enable specific SARS-CoV-2 RNA detection. This review aims to compile the state-of-the-art in ...
Improving aptamer performance with nucleic acid mimics: de novo and post-SELEX ...
Oliveira, Ricardo; Pinho, Eva; Sousa, Ana Luísa; DeStefano, Jeffrey J.; Azevedo, Nuno Filipe; Almeida, CarinaAptamers are structural single-stranded oligonucleotides generated in vitro to bind to a specific target molecule. Aptamers versatility can be enhanced with nucleic acid mimics (NAMs) during or after a selection process, also known as systematic evolution of ligands by exponential enrichment (SELEX). We address advantages and limitations of the technologies used to generate NAM aptamers, especially the applicab...
Prevalence and diversity of Staphylococcus aureus and Staphylococcal enterotoxi...
Oliveira, Ricardo; Pinho, Eva; Almeida, Gonçalo; Azevedo, Nuno F.; Almeida, Carina Manuela FernandesStaphylococcus aureus and staphylococcal enterotoxins are a serious public health concern associated with hospital and community-acquired illnesses. Dairy animals frequently shed S. aureus into the milk supply which can lead to food poisoning in humans. This study aims to investigate the prevalence and genetic diversity of S. aureus and staphylococcal enterotoxins in raw milk from the main dairy region of mainl...
Modelling aptamers with nucleic acid mimics (NAM): from sequence to three-dimen...
Oliveira, Ricardo; Pinho, Eva; Sousa, Ana Luísa; Dias, Oscar; Azevedo, Nuno Filipe; Almeida, Carina Manuela FernandesAptamers are single-stranded oligonucleotides, formerly evolved by Systematic Evolution of Ligands by EXponential enrichment (SELEX), that fold into functional three-dimensional structures. Such conformation is crucial for aptamers ability to bind to a target with high affinity and specificity. Unnatural nucleotides have been used to develop nucleic acid mimic (NAM) aptamers with increased performance, such as ...
Aptamers For Detection of Staphylococcal Enterotoxins in Food Samples
Oliveira, Ricardo; Pinho, Eva; DeStefano, Jeffrey; Azevedo, Nuno F.; Almeida, CarinaStaphylococcal food poisoning is a gastrointestinal disease caused by the consumption of food containing toxins pre-formed by enterotoxigenic Staphylococcus. Current detection of these toxins relies on time-consuming antibody-based immunoassays associated with cross-reactivity, low sensitivity, and interference from food matrices [1]. Aptamers are single-stranded oligonucleotides with a defined three- dimension...
Prevalence of Staphylococcus aureus and staphylococcal enterotoxins in raw milk...
Oliveira, Ricardo; Pinho, Eva; Almeida, Gonçalo; Azevedo, Nuno Filipe; Almeida, Carina Manuela FernandesStaphylococcus aureus and its enterotoxins (SEs) are a serious and costly concern for milk industry and public health [1]. This work aimed to characterize the prevalence of S. aureus and enterotoxins in raw milk collected in the main dairy basin region of Portugal mainland. The presence of S. aureus was confirmed in 53% of refrigerated raw milk samples collected from the bulk tank of 100 dairy farms according t...
Incorporation of lipid nanosystems containing omega-3 fatty acids in textile su...
Silva, Juliana; Mesquita, Rui; Pinho, Eva; Caldas, Ana Rita; Lopes, Carla Martins; Lúcio, Marlene; Soares, GraçaThe present work developed omega-3-loaded liposomes and nanostrucutres lipid carriers (NLC) to improve cotton textile substrates as wound dressing. The lipid nanosystems were incorporated into woven, non-woven and knitted cotton substrates by exhaustion and impregnation. Based on the physical-chemical characterization of the developed wound dressings, the textile strucute and type of lipid nanosystem dictated t...