Browsing by Author "Moreira, Felismina T.C."
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- Development of a novel electrochemical biosensor based on plastic antibodies for detection of STEAP1 biomarker in cancerPublication . Carvalho, Margarida; Rocha, Sandra Moreira; Barroca-Ferreira, Jorge; Maia, Claudio J.; Guillade, Lucía; Correa-Duarte, Miguel A.; Passarinha, Luís A.; Moreira, Felismina T.C.; Gomes, Rui M.STEAP1 is a cell surface protein of the STEAP family whose main function focuses on intercellular communication and cell growth. STEAP1 is considered a promising putative biomarker and a candidate target for prostate cancer treatment. For specific and selective detection of STEAP1, a molecularly imprinted polymers (MIP) was developed on a screen-printed electrode (C-SPE) whose surface was modified with a nanocomposite based on carbon nanotubes decorated with dendritic platinum nanoparticles (CNTs- PAH /Pt). Then, the MIPs were produced on the modified C-SPE by electropolymerization of a mixture of STEAP1 and a monomer (pyrrole-2-carboxylic acid). Then, the protein was removed from the polymeric network by enzymatic treatment with trypsin, which created the specific template cavities for further STEAP1 detection. Electrochemical techniques such as EIS and CV were used to follow the chemical modification steps of C-SPE. The analytical performance of the biosensor was evaluated by SWV in PBS buffer and in lysates of neoplastic prostate cancer cells (LNCaP) extracts. The MIP material showing a linear range from 130 pg/ml to 13 µg/ml. Overall, the biosensor exhibits essential properties such as selectivity, sensitivity and reproducibility for its application in medical and clinical research diagnosis and/or prognosis of prostate cancer.
- Electrochemical miRNA-34a-based biosensor for the diagnosis of Alzheimer’s diseasePublication . Pereira, Raquel L.; Oliveira, Daniela; Pêgo, Ana P.; Santos, Sofia D.; Moreira, Felismina T.C.Alzheimer's disease (AD) is the most common dementia type and a leading cause of death and disability in the elderly. Diagnosis is expensive and invasive, urging the development of new, affordable, and less invasive diagnostic tools. The identification of changes in the expression of non-coding RNAs prompts the development of diagnostic tools to detect disease-specific blood biomarkers. Building on this idea, this work reports a novel electrochemical microRNA (miRNA) biosensor for the diagnosis of AD, based on carbon screen-printed electrodes (C-SPEs) modified with two gold nanostructures and a complementary anti-miR-34a oligonucleotide probe. This biosensor showed good target affinity, reflected on a 100 pM to 1 μM linearity range and a limit of detection (LOD) of 39 pM in buffer and 94 aM in serum. Moreover, the biosensor’s response was not affected by serum compounds, indicating selectivity for miR-34a. The biosensor also detected miR-34a in the cell culture medium of a common AD model, stimulated with a neurotoxin to increase miR-34a secretion. Overall, the proposed biosensor makes a solid case for the introduction of a novel, inexpensive, and minimally invasive tool for the early diagnosis of AD, based on the detection of a circulating miRNA overexpressed in this pathology.
- Electrochemical miRNA-34a-based biosensor for the diagnosis of Alzheimer’s diseasePublication . Pereira, Raquel L.; Oliveira, Daniela; Pêgo, Ana P.; Santos, Sofia D.; Moreira, Felismina T.C.Alzheimer's disease (AD) is the most common dementia type and a leading cause of death and disability in the elderly. Diagnosis is expensive and invasive, urging the development of new, affordable, and less invasive diagnostic tools. The identification of changes in the expression of non-coding RNAs prompts the development of diagnostic tools to detect disease-specific blood biomarkers. Building on this idea, this work reports a novel electrochemical microRNA (miRNA) biosensor for the diagnosis of AD, based on carbon screen-printed electrodes (C-SPEs) modified with two gold nanostructures and a complementary anti-miR-34a oligonucleotide probe. This biosensor showed good target affinity, reflected on a 100 pM to 1 μM linearity range and a limit of detection (LOD) of 39 pM in buffer and 94 aM in serum. Moreover, the biosensor’s response was not affected by serum compounds, indicating selectivity for miR-34a. The biosensor also detected miR-34a in the cell culture medium of a common AD model, stimulated with a neurotoxin to increase miR-34a secretion. Overall, the proposed biosensor makes a solid case for the introduction of a novel, inexpensive, and minimally invasive tool for the early diagnosis of AD, based on the detection of a circulating miRNA overexpressed in this pathology.
- Enhanced detection with prussian blue-based nanocubes: a novel electrochemical biosensor for bovine serum albumin analysis: microfluidic integrationPublication . Santos, Andréa dos; Oliveira, Daniela; Martins, Gabriela; Moreira, Felismina T.C.(Introduction) Early diagnosis of biomarkers is crucial for optimizing treatments and increasing survival rates. Direct and cost-effective assays are important for point-of-care (PoC) testing. Bovine serum albumin (BSA) monitoring indicates liver and kidney function and aids in the assessment of diseases such as cirrhosis and chronic kidney disease. An innovative electrochemical biosensor was developed in which a platinum electrode was decorated with manganese-based Prussian blue nanocubes (PB-NC). A molecularly imprinted polymer (MIP) was created on the electrode surface by electropolymerization of phenol in the presence of BSA using cyclic voltammetry (CV). The template was removed with proteinase K and a mixture of methanol and acetic acid. Square wave voltammetry (SWV) characterized the performance of the sensor, which exhibited high sensitivity and allowed detection of BSA at nanomolar levels.
- Homemade 3-carbon electrode system for electrochemical sensing: Application to microRNA detectionPublication . Carneiro, Mariana C.C.G.; Moreira, Felismina T.C.; Dutra, Rosa A.F.; Fernandes, Rúben; Sales, M. Goreti F.The homemade production of carbon screen-printed electrodes (C-SPEs) with a three‑carbon electrode system is reported, along with its application in electrochemical sensing. It is highlighted herein as main novelty that a simple carbon ink may be employed in the preparation of the 3-electrode system, including the pseudo-reference electrode, thereby avoiding the addition of silver or other suitable metal and simplify the construction of such devices, reducing costs and time. Screen-printed technology was employed to produce the 3-electrodes and the corresponding electrical paths. This was achieved by the manual application of a commercial carbon ink into a polyvinyl chloride (PVC) substrate allowing the production of > 20 SPEs. The optimization of the SPE assembly was made by univariate mode, until the best electrical features of the electrode-solution interface were achieved. Several electrochemical techniques were used for this purpose, namely cyclic voltammetry (CV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). Raman Spectroscopy and Thermogravimetric Analysis (TGA) were also used for materials and electrode surface characterization. The usefulness of such devices was tested by modifying the working electrode with a sensing layer for microRNA-107, a potential biomarker in Alzheimer's Disease (AD). For this purpose, the surface was functionalized with carboxylic groups, activated by carbodiimide reaction and bound to a suitable oligonucleotide probe containing the complementary sequence. Finally, the microRNA-107 sequence hybridized with its probe, proving the efficiency of the C-SPEs in electrochemical sensing. Overall, this study brings into light the possibility of preparing simple homemade electrodes with a 3‑carbon electrode system that stands out by the low cost, disposability and versatility of the presented platform, holding a great potential for application in point-of-care devices using electrochemical sensing.
- Integration of microfluidics and nanoezyme peroxidase for colorimetric detection of neurotransmittersPublication . Sousa, Cristina; Chiussi, Stefano; Moreira, Felismina T.C.The integration of Microfluidics and Nanozyme peroxidase for the Colorimetric detection of Neurotransmitters represents a cutting-edge approach in neurochemical analysis. Microfluidics allows precise manipulation of small fluid volumes, reducing reagent consumption and accelerating reactions while integrating multiple analytical steps on a single chip. Nanozyme peroxidases, mimicking natural peroxidases, provide enhanced stability and catalytic efficiency at a lower cost. The colorimetric detection mechanism signals the presence of neurotransmitters through a visible color change, making it sensitive and easy to interpret for real-time analysis. Detecting neurotransmitters like acetylcholine(ACH) is crucial for understanding and diagnosing various neurological conditions. Acetylcholine plays a key role in physiological processes such as muscle activation, memory function, and synaptic transmission. Abnormal levels are linked to disorders like Alzheimer's disease, myasthenia gravis, and Parkinson's disease. Accurate measurement aids in early diagnosis, monitoring disease progression, and evaluating treatment efficacy. A reliable detection method can advance our understanding of brain function and neurotransmitter dynamics. Real-time monitoring provides insights into how neurotransmitter fluctuations correlate with cognitive functions, behaviors, and responses to stimuli, essential for developing new therapeutic strategies and discovering novel drugs targeting neurotransmitter systems.
- Integration of the microfluidic and plastic body for the detection of a biomarker associated with Alzheimer diseasePublication . Vinagre, Inês; Chiussi, Stefano; Moreira, Felismina T.C.
- Plastic antibody for the diagnosis of acute myocardial infarctionPublication . Ricardo, Jacinta; Martins, Gabriela; Moreira, Felismina T.C.(Introduction) Novel application Plastic Antibody that responds to a cardiac biomarker, myoglobin (Myo). Imprint stage with electropolymerization of ortho-phenylenediamine (OPD) in the presence of Myo. Template removal from polymeric matrix digested by trypsin. The films acted as biomimetic artificial antibodies and were fabricated on a screen-printed platinium (Pt) electrode (SPE) modified with electroactive Prussian blue nanocubes (PBNCs) to take a step towards disposable sensors for point-of-care applications. The devices showed linear responses to Myo in SWV assays up to 0.01 and 10000 ng/mL.
- Plastic antibody for the diagnosis of acute myocardial infarctionPublication . Ricardo, Jacinta; Martins, Gabriela V.; Moreira, Felismina T.C.(Introduction) Myoglobin (Myo) is the first cardiac biomarker to be released into the bloodstream after the onset of symptoms of Acute Myocardial Infarction (AMI), allowing earlier detection of this disease. Novel application based on Plastic Antibody that responds to a cardiac biomarker, Myo. Imprint stage with electropolymerization of ortho-phenylenediamine (OPD) in the presence of Myo. Template removal from polymeric matrix digested by trypsin. The biomimetic film was fabricated on platinum screen-printed electrodes (Pt-SPE) modified with electroactive Prussian blue nanocubes (PBNCs).
- Screen-printed electrode produced by printed-circuit board technology. Application to cancer biomarker detection by means of plastic antibody as sensing materialPublication . Moreira, Felismina T.C.; Ferreira, M.Judite M.S.; Puga, José R.T.; Sales, GoretiThis research work presents, for the first time, a screen-printed electrode (SPE) made on a PCB board with silver tracks (Ag) and a three electrode configuration (AgxO-working, AgxO-counter and Ag/AgxO-reference electrodes), following the same approach as printed-circuit boards (PCBs). This low cost and disposable device was tested for screening a cancer biomarker in point-of-care. The selected biomarker was carcinogenic embryonic antigen (CEA) protein, routinely used to follow-up the progression of specific cancer diseases. The biosensor was constructed by assembling a plastic antibody on the Ag-working electrode area, acting as the biorecognition element of the device. The protein molecules that were entrapped on the polymer and positioned at the outer surface of the polypyrrole (PPy) film were removed by protease action. The imprinting effect was tested by preparing non-imprinted (NPPy) material, including only PPy as biorecognition element. Infrared and Raman studies confirmed the surface modification of these electrodes. The ability of the sensing material to rebind CEA was measured by several electrochemi-cal techniques: cyclic voltammetry (CV), impedance spectroscopy (EIS) and square wave voltammetry (SWV). The linear response ranged from 0.05 to 1.25 pg/mL against logarithm concentration. Overall, producing screen-printed electrodes by means of conventional PCB technology showed promising features, mostly regarding cost and prompt availability. The plastic antibody-based biosensor also seems to be a promising tool for screening CEA in point-of-care, with low response time, low cost, good sensitivity and high stability.