Potentiometric Biosensor Based on Artificial Antibodies for an Alzheimer Biomarker Detection

• Autor(a) principal: Ribeiro, Sónia Claúdia
• Data de Publicação: 2022
• Outros Autores: Fernandes, Rúben, Moreira, Felismina, Ferreira Sales, Maria Goreti
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.22/21866
• topic: Amyloidβ-42; Molecularly imprinted polymers; Potentiometric sensor; Alzheimer biomarker

This paper presents a potentiometric biosensor for the detection of amyloidβ-42 (Aβ-42) inpoint-of-care analysis. This approach is based on the molecular imprint polymer (MIP) technique,which uses covalently immobilised Aβ-42 to create specific detection cavities on the surface of single-walled carbon nanotubes (SWCNTs). The biosensor was prepared by binding Aβ-42 to the SWCNTsurface and then imprinting it by adding acrylamide (monomer), N,N′-methylene-bis-acrylamide(crosslinker) and ammonium persulphate (initiator). The target peptide was removed from thepolymer matrix by the proteolytic action of an enzyme (proteinase K). The presence of imprintingsites was confirmed by comparing a MIP-modified surface with a negative control (NIP) consistingof a similar material where the target molecule had been removed from the process. The abilityof the sensing material to rebind Aβ-42 was demonstrated by incorporating the MIP material asan electroactive compound in a PVC/plasticiser mixture applied to a solid conductive support ofgraphite. All steps of the synthesis of the imprinted materials were followed by Raman spectroscopyand Fourier transform infrared spectroscopy (FTIR). The analytical performance was evaluated bypotentiometric transduction, and the MIP material showed cationic slopes of 75 mV-decade−1inbuffer pH 8.0 and a detection limit of 0.72μg/mL. Overall, potentiometric transduction confirmedthat the sensor can discriminate Aβ-42 in the presence of other biomolecules in the same solution