(329e) Understanding Oligonucleotide Hybridization on Single-Walled Carbon Nanotube Corona Phases for Viral Sensing Applications

Single-walled carbon nanotubes (SWCNTs) with tailored corona phases, or adsorbed molecules, have emerged as a promising material for sensing as the adsorption of an analyte can be specifically transduced as a modulation of their photoluminescence (PL). One such corona phase ripe for engineering is single-stranded DNA (ssDNA), where subsequent sequence specific hybridization can result in PL emission wavelength shifts. However, despite previous studies, the design principles for these ssDNA SWCNT constructs (ssDNA-SWCNTs) to result in both hybridization in conjunction with photophysical response is not well understood. In this work, we study the use of ssDNA-SWCNTs as a label-free approach to detect DNA and RNA oligonucleotides chosen specifically from regions of the SARS-CoV-2 genome for specific sensing. The complementary interactions of DNA and RNA oligonucleotides on the SWCNT corona results in the blue-shift of SWCNT PL emission wavelength with LOD of 10 nM following 1-hour incubation. Sensor specificity can be significantly improved, as compared to random-sequence controls by one order of magnitude, through the inclusion of additional nucleic acids as anchors in the adsorbed corona phase. (GT)₁₅ anchor resulted in greater wavelength shifts for both DNA and RNA targets compared to (AT)₁₅ and (CT)₁₅. Investigating hybridization incubation conditions show that bath sonication after incubation resulted in up to 22.1 percent enhancement in blue-shift. Additionally, co-incubation with 1 percent saliva preserved the blue-shift without compromising sensor specificity, while surfactant addition resulted in loss of sensor specificity. This work elucidates additional design principles for ssDNA-SWCNT-based hybridization nanosensors for targeting specific sequences toward the development of an adaptable point-of-care rapid test against nucleic acid targets.