Publication details
Electrochemical sensing of prion proteins using quantum dots
| Authors | |
|---|---|
| Year of publication | 2012 |
| Type | Article in Proceedings |
| Conference | The 1st International Conference on Nanomaterials: Fundamentals and Applications, Book of Abstracts |
| MU Faculty or unit | |
| Citation | |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | prion protein;Creutzfeld-Jakob disease;quantum dots;fluorescence;biosensor |
| Description | The prion protein (PrP) is involved in neurodegeneration via its conversion from the normal cellular form, PrPC, to the infectious form, PrPSc, which is the causative agent of the transmissible spongiform encephalopathies (TSEs) including Creutzfeldt-Jakob disease (CJD). In spite of great effort in this field, diagnostics of prion protein caused diseases represents a sort of challenge. Sensitive and specific detection of abnormal prion protein in blood could provide a diagnostic test or screening assay for animal and human prion diseases. Therefore, diagnostic tests of prion diseases present a unique challenge requiring development of novel assays exploiting properties uniquely possessed by this misfolded protein complex. The characterization and analysis of biomolecules and biological systems in the context of intact organisms is known as in vivo research. A new and exciting direction of research for quantum dots (QDs) is their application as a contrast agent for in vivo imaging. Excellent optical properties of QDs (namely high quantum yield, broad absorption spectra and narrow, symmetric fluorescence spectra from UV to NIR, large effective excitation and emission Stokes shifts), long life-time (high resistance to photobleaching) compared to ordinary fluorophores and stability (resistance to photo- and chemical degradation) predestinate them in usage for imaging and as optical probes for detection of peptides, proteins, nucleic acids and other biomolecules [1-4]. One of our main aims is to find an easy way how to study QDs. Primarily, we optimized microwave synthesis of CdTe QDs, which was coated with mercapto-propionic acid. These particles were then characterized and their electrochemical behaviour was studied using differential pulse voltammetry at hanging mercury drop electrode. Based on our results, it can be concluded that QDs gave several signals related to various chemicals, which was used to their synthesis, and one (-0.75 vs. Ag/AgCl/3 M NaCl) related to QDs itself. Based on the changes of this signal, we can easily quantify the dots and estimate their stability. Moreover, we studied the interactions of QDs with prion proteins. Detection limit (3 S/N) was estimated as 1 fg in 5 microl. Results showed that the electrochemical signals of prion protein were strongly quenched by CdTe QDs. This phenomenon can be considered as a first step of suggesting of a biosensor for determination of prions in real samples without a sample pre-treatment. |