(339e) Chirality-Specific Protein Adsorption on Single-Walled Carbon Nanotubes

Semiconducting single-walled carbon nanotubes (SWCNTs) serve as versatile near-infrared (NIR) fluorophores, offering a substrate for both noncovalent and covalent modification to create sensors that display modulated fluorescence upon target analyte interaction. Such sensors can be applied in basic biological research and biomedical diagnostics. The fluorescence emission of SWCNTs depends on their lattice structure, or so-called chirality (n,m), enabling the development of multi-color biosensors, including those for cancer biomarker detection in human plasma. However, when exposed to complex body fluids, such biosensors are influenced by protein corona formation, a process in which proteins from the surrounding fluid absorb to the nanotube surface. Profiling protein adsorption on mixed-chirality SWCNTs has revealed the composition and driving forces of protein corona formation, leaving chirality-specific interactions unexplored. Building on this work^[1], we hypothesize that the nanotube chirality, and thus diameter and surface curvature, play a key role in determining protein-nanotube interactions and corona formation. Yet, chirality-specific interactions remain difficult to study due to the demanding production of sorted SWCNT material and hence limited quantities for proteomic investigations. Here, we employ mass spectrometry analysis adapted from single-cell-proteomics to study the protein corona composition on chirality-pure SWCNTs. Aqueous two-phase extraction facilitates the reliable sorting of single-color probes. Functionalizing these single-chirality SWCNTs with biopolymers such as ssDNA then creates a biosensor. Initially, we analyze protein adsorption from human plasma on a single chirality, specifically (6,5)-SWCNTs, modified with various oligonucleotide (ssDNA) sequences that display different sensing and nanotube-binding properties, to assess the impact of surface chemistry on the resultant protein corona profile. Subsequently, we investigate how protein adsorption is influenced by SWCNT chirality bearing the same surface modification. Notably, our protocol enables the recycling of precious chirality-sorted SWCNT material. We establish a foundation for correlating NIR fluorescence sensing of disease states with protein biomarker adsorption. Overall, our study unveils how SWCNT surface chemistry and chirality affect protein adsorption, enabling future targeted biosensing approaches.

1. Pinals, R. L. et al. Quantitative Protein Corona Composition and Dynamics on Carbon Nanotubes in Biological Environments. Angew. Chemie - Int. Ed. 59, 23668–23677 (2020).