Browsing by Author "Martins, Gabriela"
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- Bioinspired host-tailored polymers based on molecular imprinting for cytokine assessmentPublication . Ferreira, Bianca; Correa-Duarte, Miguel; Marques, Arcelina; Moreira, Felismina; Martins, GabrielaMolecular imprinting undergone a substantial boost driven by the awareness of molecularly imprinted polymers (MIPs)-ligand recognition skills. In particular, the introduction of natural-based compounds like cyclodextrins into the structural scaffold of synthetic recognition elements attracted great importance as a novel route to design more friendly-environments for protein binding, while promoting higher selectivity features. Herein, carbon electrodes doped with platinum nanoparticles supported on multiwalled carbon nanotubes and functionalized with polyallylamine (MWCNTs-PAH/Pt) were electrochemically modified with an imprinted sensing layer of poly(β-cyclodextrin-pyrrole) (poly(β-CD-Py)) towards interleukin 6 (IL-6) monitoring. The analytical performance of the biosensor was evaluated by using Cyclic Voltammetry and Electrochemical Impedance Spectroscopy techniques. Along the assembly, experimental parameters like nanomaterial deposition, monomer-protein concentrations and template removal solutions were carefully optimized and discussed. Furthermore, the electrodeposited film was characterized in terms of composition, morphology and structure using scanning electron microscopy (SEM) and Raman spectroscopy. Under optimal conditions, the developed sensor was able to rebind IL-6 over a wide linear range [1 pg/mL – 100 ng/mL], displaying high sensitivity, quick electrochemical response, and specific binding of the target molecule. Overall, this work reported the relevance of using hostguest complexes directly embedded in polymeric chains to generate newly controlled electrochemical sensors holding great potential for protein biosensing.
- Enhanced detection with Prussian blue-based nanocubes: a novel electrochemical biosensor for bovine serum albumin analysisPublication . Santos, Andréa dos; Martins, Gabriela; Moreira, FelisminaEarly diagnosis of relevant biomarkers is nowadays crucial for optimizing therapeutic approaches and elevating survival rates. Therefore, the development of straightforward, cost-effective, and user-friendly diagnostic assays holds significant value for use in Point-of-Care (PoC) testing. In this context, employing a nanomaterial-redox probe approach in electrochemical biosensing devices not only enhances sensitivity and accelerates response times but also ensures stability, thereby enabling reliable detection of target analytes. The monitorization of Bovine Serum Albumin (BSA) can serve as valuable indicators of both liver and kidney function (Belinskaia et al., 2021; Cheng et al., 2023). Liver dysfunction, such as in liver cirrhosis or hepatitis, may lead to decreased BSA levels (hypoalbuminemia), while kidney dysfunction, as in chronic kidney disease or acute kidney injury, can result in elevated BSA levels (hyperalbuminemia). Thus, tracking BSA levels offers valuable insights into the function and dynamics of these organs, aiding clinicians in assessing the severity of liver and kidney diseases and guiding appropriate treatment strategies for affected individuals. Herein, an innovative electrochemical biosensor was developed using a platinum screen-printed electrode (Pt-SPE) decorated with Manganese-based Prussian Blue Nanocubes (K2Mn[Fe(CN)6]·2H2O, Mn/PBNCs) for selective and sensitive determination of BSA protein. The biorecognition layer, constituted by a molecularly imprinted polymer (MIP), was fabricated on the surface of Mn/PBNCs-Pt/SPE by electropolymerization of phenol, in the presence of the target protein (BSA) by means of cyclic voltammetry (CV). Subsequently, the template was removed from the polymer matrix using proteinase K and a mixture of methanol and acetic acid. In parallel, a non-imprinted material (NIP) was constructed in the absence of the target protein. Both MIP and NIP resulted in a nonconducting and electrically inactive film on the modified electrode surface. Along the optimization, both electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) were employed to characterize the electrochemical performance of the MIP sensor. Overall, the incorporation of the nanomaterials onto the electrode surface resulted in an electrochemical biosensor exhibiting enhanced responsiveness to BSA detection, enabling the detection of this biomarker down to the nanoMolar level.
- 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.
- Flexible 2D and 3D conductive hydrogel platforms for wearable applicationsPublication . Aguiar, Leonor; Pereira, Raquel; Sharma, Sanjiv; Martins, GabrielaHydrogels have risen as exceptionally promising support materials in the development of novel wearable electronic devices. Their remarkable biocompatibility coupled with customizable mechanical features make these biomaterials ideal choices for applications involving direct contact with biological tissues. In this study, a simple and straightforward manufacturing process using bio-sourced polysaccharide chitosan (Chi) was employed for the fabrication of flexible and transparent biopolymeric membranes. Subsequently, this two-dimensional (2D) platform was made conductive, through a one-step process, by utilizing an optimized ratio of chitosan, lactic acid, and silver nanowires (Chi-LaA-AgNWs) dispersion. These electrodes were produced by screen printing technique. Furthermore, a solvent casting technique employing inverse polydimethylsiloxane (PDMS) molds was used to fabricate mechanically stable chitosan microneedles (Chi-MNs). These three dimensional (3D) structures were enriched with a carbon-based ink during the casting of concentrated Chi hydrogels into the mold while utilizing centrifugal forces. The electrochemical properties of the fabricated 2D and 3D conductive platforms were evaluated through cyclic voltammetry (CV). Along this study, the water swelling properties of Chi hydrogels were investigated by incorporating natural crosslinkers and plasticizing compounds like citric acid, glycerol, and sorbitol. Optimization of fabrication, physico-chemical and morphological analysis of the membranes and MNs were also performed. Ultimately, the use of Chi combined with environmentally friendly agents enabled the fabrication of flexible conductive platforms holding good stability, uniformity, and desirable electrical attributes.
- 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.