Gold-Coated Black Silicon Nanostructured Surfaces for SERS and SALDI-MS Multimodal Imaging of Biological Applications

Identifier:  TDX:3191

Handle: https://hdl.handle.net/20.500.11797/TDX3191

Authors:  Iakab, Stefania-Alexandra

Abstract:
Characterising in situ the molecular composition of biological tissues is an indispensable tool in clinical, pharmaceutical and forensic research. Imaging modalities such as mass spectrometry imaging and Raman spectroscopy imaging employ nanostructured materials for addressing challenges such as low sensitivity, specificity and lateral resolution. The aim of this thesis is to design, fabricate, evaluate and apply a gold- and silicon-based nanostructured substrate (named AuBSi) compatible with surface-assisted laser desorption/ionization (SALDI) and surface-enhanced Raman spectroscopy (SERS) imaging applications. Results demonstrate that the AuBSi substrate is reproducible, user-friendly, cost effective and highly reliable. It ensures easy sample preparation and is fully compatible with both imaging modalities, enabling a genuine multimodal approach. We show that there is a unification between SALDI and SERS data formats that allows the full integration of the image processing workflow and the straightforward coregistration of images. We tested the imaging capabilities of the AuBSi on several standard solutions, animal tissue sections (mouse liver, kidney and brain) and fingerprints. The multimodal analysis of fingerprints highlighted the excellent capabilities of the substrate to couple SALDI and SERS imaging, while dealing with the challenges of each technique. Thus, the AuBSi substrate developed in this thesis facilitates targeted and/or untargeted in situ metabolomics studies for various fields such as clinical, environmental, forensics, and pharmaceutical research.