Development of SERS substrates for the characterization of cellular systems and the determination of molecules of interest
Aguilar Hernández, Iris Anahí
MetadataShow full item record
Raman spectroscopy is a powerful vibrational spectroscopy technique that provides useful information regarding the chemical composition of a sample. It is a label-free technique that can be successfully applied for both single analyte detection and the analysis of complex matrices. The only main limitation of Raman spectroscopy is the inherent low scattering efficiency. Surface Enhanced Raman Spectroscopy (SERS) is employed to overcome this limitation. SERS active structures are typically in the form of colloidal solutions, or as solid substrates with metallic nanostructures on the surface. The work included in this dissertation explores the development of SERS substrates for (a) the detection of a single molecule of interest, and (b) the analysis of cellular systems. For the detection of molecules of interest, two studies were carried out: In the first study, the ideal synthesis conditions of colloidal silver nanoparticles that rendered the highest SERS enhancement was explored via principal component analysis (PCA). The selected silver nanoparticles were used for the ultrasensitive detection of phenolic compounds in solution. The second work focused on the development of solid substrates, where gold nanoparticles were synthesized and immobilized on a carbon nanofibers matrix and enhancement capacity of the SERS substrate was evaluated with Rhodamine 110. The use of SERS for the analysis of biological systems was also explored. First, the effect of an oxidative agent (CdTe quantum dots) on the freshwater microalgae H. pluvialis was studied with SERS via colloidal gold nanoparticles. Mammalian cell lines were also analyzed; Colloidal concave gold nanocubes were synthesized and immobilized onto a solid substrate for SERS enhancement of HeLa cells, showing that solid SERS substrates are also suitable for cell analysis. Finally, radiation resistant and radiation sensitive murine leukemia sublines were characterized for the first time by normal Raman spectroscopy and SERS, with the aim of contributing the development of predictive radiosensitivity assays. SERS substrates in colloidal and solid form were developed, and successfully used for the label-free detection of analytes in solution and complex biological samples, showing the versatility of SERS and contributing to this growing multidisciplinary field.
The following license files are associated with this item: