Electrochemical and optical nanomaterial-based biosensors for diagnostic applications
- Autores: Alejandro Chamorro García
- Directores de la Tesis: Antonio Villaverde Corrales (dir. tes.), Arben Merkoçi (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2015
- Idioma: inglés
- Tribunal Calificador de la Tesis: Emmanuel Delamarche (presid.), Xavier Muñoz Berbel (secret.), Sergi Gassó Pons (voc.)
- Materias:
- Enlaces
- Resumen
This thesis describes the study and development of new biosensing approaches based on novel properties of nanomaterials for the detection of proteins and DNA. The work has been performed in basis of two sensing platforms: first platform, the carbon screen-printed electrodes (SPCEs), were used in a more sensitive detection of gold nanoparticles (AuNPs) through electric impedance measurements. Furthemore, the same platform (SPCE) was adapted through polythinione films and iridium oxide nanoparticles (IrOxNPs) for the detection of specific DNA sequences in a label free assay. The second platform, paper-based platforms in format of Flow Immunoassay (LFIA), using gold nanoparticles as labels is adapted for the detection of a specific protein, Parathyroid like Hormone (PTHLH), with the aim to find a new strategy for simpler, non-hazardous, cheaper and faster detection of the protein. In Chapter 1 a general overview of the application of nanomaterials for the improvement of biosensors and its application in the field of diagnostics and biomarkers detection is presented. In Chapter 2 the objectives of the thesis are presented. Use of SPCE as platform for detection of gold nanoparticles (AuNPs) through electric impedance measurements is presented in Chapter 3. The developed technique is successfully applied in the detection of AuNPs of different sizes, and in a magnetoimmnuoassay for the detection of a model protein using AuNPs as electrochemical labels. In Chapter 4, a novel biosensor for the detection of DNA is presented. The system is based in SPCE modified with polymer films and Iridium Oxide nanoparticles, where capturing DNA sequences have been immobilized. Detection of target DNA sequences is performed through electric impedance measurements, based in the blocking effect of the DNA against the diffusion of a redox indicator to the surface of the electrode. A label free immunoassay for detection of specific sequences of Leishmania parasite¿s DNA is shown. In Chapter 5 general conclusions and future perspectives of the presented work are discussed. In Annex A the work related to the paper-based platform for protein detection is presented. In this annex, detection of a specific protein (parathyroid like hormone, PTHLH) through LFIA strips is described. The developed LFIA strips represent a cheaper, faster and non-hazardous alternative to current available systems for PTHLH detection. Limits of detection (LOD) in the range of ng mL-1 for PTHLH in real samples (cell culture media, cell lysates) are reported. Furthermore, the developed system is challenged using human serum spiked with PTHLH, proving the potential of the system to detect PTHLH In human serum. In Annex B the work carried out in a research stay is presented. In this section fabrication of electrochemical DNA (E-DNA), and electrochemical aptamer (E-Ab) biosensors is described. The aim of the work was focused on adapting the E-DNA and E-Ab technology to SPCE, using AuNPs as connecting platform between the thiol modified DNA and the SPCE. Annex C represents a research done as a continuation of a previous one done in the group related mostly to the study of compatible materials with interest to be used as cells growth platforms with interest in sensing. As continuation of this work, in Annex C the conditions and materials previously selected to grow cells are applied in a nanochannel platform for the detection of a protein secreted by the cells grown directly on the sensing platform.
