Multifunctional Au–CNT nanohybrid for highly sensitive catalytic and affinity biosensing applications

Carbon nanotubes (CNTs) have unique intrinsic properties, such as huge surface areas, homogenous pore size distributions, and nanoscale dimensions, making them highly promising for biosensing applications. However, their limited dispersion in biological media and increased resistance hinder efficient charge transfer, necessitating innovative strategies to enhance their performance. This study presents a novel and facile approach for synthesizing multifunctional gold nanoparticle (AuNP)-decorated CNT (Au-CNT) nanohybrids using hetero-functional polyethylene glycol (PEG) as a linker <i>via</i> EDC/NHS chemistry. This approach ensures the covalent and uniform decoration of AuNPs over the surface of CNTs, significantly improving their dispersion, chemical stability, and biocompatibility while preserving their electrochemical activity. Comprehensive morphological, chemical, and electrochemical characterizations confirm improved dispersion and enhanced electron transfer capabilities. To validate its practical application, a proof-of-concept electrochemical sensor is developed for H₂O₂ and glucose detection. Comparative analysis reveals that the Au-CNT nanohybrid exhibits an increase in sensitivity over pristine CNTs, demonstrating its superior catalytic performance. These findings highlight the potential of Au-CNT nanohybrids as versatile platforms for advanced electrochemical catalytic and affinity biosensing applications.