Development of gold nanoparticles-based platforms for biomarker detection

Abstract

This dissertation focuses on the development of colorimetric, mass spectrometric, and electrochemical platforms for biomarker detection, with gold nanoparticles as the core material. The initial part of the research involves the synthesis of a nanocomposite composed of MXene, a two-dimensional nanosheet material with a ternary carbide structure, combined with gold nanoparticles that exhibit specificity toward cysteine, a biomarker for Alzheimer's disease. The specificity arises from the thiol group (-SH) in cysteine, which strongly binds to the surface of gold nanoparticles through Au–S bonding. This nanocomposite enhances the performance of both colorimetric and mass spectrometric sensors, which show consistent and linear detection of cysteine in urine within a concentration range of 0.1 to 0.5 g L-1. This range covered the cut-off concentration of 0.25 g L-1, which differentiate between healthy and patient. The latter part of the dissertation is divided into two main sections. The first section compiles fundamental information on Laser-Induced Graphene (LIG), a material rapidly fabricated through a chemical-free laser process that suitable for both industrial and laboratory-scale graphene production. This section covers LIG fabrication methods and its development for clinical applications. The second section focuses on the integration of gold nanoparticles with LIG to develop electrochemical and mass spectrometric biosensors for sarcosine detection in urine, a biomarker for prostate cancer. The biosensor demonstrates a linear detection range of sarcosine from 5 to 50 μM, covering the cut-off concentration of 25 μM that discriminates between healthy and affected conditions. Overall, both gold nanoparticle-based platforms developed in this work show high potential for future advancement in biomarker detection and diagnosis applications.