Morphologies of Single-Stranded DNA Oligomers Adsorbed on Carbon Nanotube-Based Sensors in Solution using X-ray Scattering Interferometry

Single-walled carbon nanotubes (SWCNTs) with adsorbed nucleic acids are used as sensors in biological experiments. Different single-stranded DNA (ssDNA) sequences alter the specificity of affinities of the ssDNA-SWCNT complexes to different analyte targets. In these experiments, we determined the morphologies of two adsorbed ssDNA oligomers using X-ray scattering interferometry (XSI). Previous to this study, the morphologies of ssDNAs were calculated predominantly via computational models, or where the ssDNA-SWCNTs were dehydrated. We conjugated gold nanoparticles (AuNPs) to (GT)6 or (GT)15 ssDNA oligomers to boost X-ray scattering prior to adsorbing them onto SWCNT surfaces, and performed XSI experiments in solution. The data suggests the (GT)6 oligomers make a series of highly-ordered stacked rings along the the length of the SWCNT, while the (GT)15 oligomers wrap SWCNTs in a less-ordered periodic fashion. Dopamine then elicits a simultaneous axial elongation and radial constriction of the adsorbed ssDNA oligomers on the SWCNT surface. More details are available in the corresponding JACS journal article linked below.

AuNPs ranging from 5.9-7.2 nm in diameter were conjugated to the 5’ end of ssDNA oligomers. The AuNP-ssDNAs (6 and 15 nucleotides) were then adsorbed to the surfaces of SWCNTs, forming an AuNP-ssDNA-SWCNT suspension. We then collected XSI in high-throughput mode at the SIBYLS beamline using a Tecan Evo liquid Handling robot. Each sample was irradiated with X-rays at 1.2398 Å for 5 seconds with a 0.1 second frame-rate with a sample to detector distance of 2.07 meters. The data here represent the scattering data with buffer background subtraction.

All X-ray Scattering Interferometry curves for the publication Rosenberg DJ et al. "Mapping the Morphology of DNA on Carbon Nanotube-Based Sensors in Solution using X-ray Scattering Interferometry" J. Am. Chem. Soc. 2024, 146, 386−398. See DOI link below.

2023-05-23

2025-02-10

HT-SAXS

https://doi.org/10.1021/jacs.3c09549

Advanced Light Source

SIBYLS BL12.3.1

1.2398 Å

2.0 m

Sample:

• Macromolecule 1: ssDNA-AuNP-SWCNT
• Sample Full Name: ssDNA conjugated to gold nanoparticles adsorbed on Single-walled carbon nanotubes
• Sample Type: Nanoparticle
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