(Invited) Quantum Defects in Carbon Nanotubes as Tunable Chemical Dimension for Biosensing

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2025-01; no. 11; p. 921
• Main Author: Kruss, Sebastian
• Format: Journal Article
• Language: English
• Published: The Electrochemical Society, Inc 11.07.2025
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2025-0111921mtgabs

Single wall carbon nanotubes (SWCNTs) are 1D nanomaterials that show fluorescence in the near infrared (NIR, >800 nm). They have been assembled with biopolymers such as DNA to form highly sensitive molecular sensors. Such optical sensors change their fluorescence when they interact with analytes. In the past, covalent chemistry was less explored to functionalize SWCNTs as it impairs NIR emission. However, certain sp3 defects (quantum defects) and sp 2 guanin defects in the carbon lattice have emerged that preserve NIR fluorescence, introduce novel photophysics such as red-shifted emission features and provide novel opportunities for surface chemistry. Here, I present sp 3 and sp 2 quantum defects that serve as anchor points for biomolecules or change the photophysics. We show surface functionalization with aptamers, measure experimentally the number of defects per SWCNT and their impact on photophysics. Additionally, we demonstrate how perturbation of a system with quantum defects reveals the photophysical mechanism of sensors and provides opportunities for novel sensing concepts. These approaches are used to demonstrate sensing of different important biomolecules from small molecules such as neurotransmitters to proteins. Additionally, we combine sp 2 guanine defects and sp3 defects for biosensing applications. In summary, quantum defects open a new chemical dimension to tailor photophysical properties as well as surface chemistry of SWCNTs for biosensing applications.