Disposable immunosensor for diagnosis of Human Cytomegalovirus infection

• Autor(a) principal: Silva, Hugo Flávio Cunha da
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/5633
• topic: Antibody Immobilization; Boronic Acid.; Diazonium Salts; Glutaraldehyde; Human Cytomegalovirus; Immunosensor

Human Cytomegalovirus (HCMV) is a herpes virus that establishes a lifelong latent infection which, in most of the immunocompetent individuals is normally subclinical. Severe infections occur more frequently in immunocompromised ones, or those with immature immune system, for which can be fatal. Glycoprotein B (gB) is the dominant antigen of HCMV envelope being regarded as a promising component in the establishment of new diagnostic tests. Nowadays there are several diagnosis methods, however, these are expensive, or/and require long time to perform, or/and need skilled operators, or even leads to the possibility of false results. So, in previously work, a disposable immunosensor was developed based on electrochemical silver oxidation as response for gB concentration increasing, using screen-printing carbon electrodes. This method allows a faster and inexpensive way to detect that viral protein. Despite that, a lack on device reproducibility and sensitivity, due to the randomly antibody adsorption was found. It is known that the oriented immobilization has become critical for optimized antigen detection on solid surfaces; therefore, those results lead us to employ other immobilization techniques to improve the immunosensor performance. In this work the immobilization of antibodies was carried out through glutaraldehyde cross-linking, by covalent immobilization using diazonium salts and finally by using the boronic acid affinity towards the carbohydrate present on the antibody molecules. The results were conclusive only for the cross-linking, which has disadvantages when compared with adsorption. Additionally, the importance of the gB on diagnosis tests for HCMV, lead us to study its isolated electrochemical behavior. Questionable results were found demonstrating the impossibility of its use in the determination of gB in biological samples.