Exploring the Immunostimulatory Effects of Gold-SNA Through Variable DNA Lengths

Student’s Name: Beck Lindholm Home Institution: Colorado College NNCI Site: ShyNE @ Northwestern University REU Principal Investigator: Dr. Chad A. Mirkin REU Mentors: Ana Clara Z. Leal, Julia Petrescu, and Dr. Sergej Kudruk Abstract: The spherical nucleic acid (SNA) form factor in which a nanoparticle core is radially functionalized with adjuvant DNA has become a promising delivery platform in cancer vaccinology due to its high rate of cellular uptake and immune activation. The proper selection of an adjuvant is critical to elicit a specific immune response. SNAs adorned with DNA containing cytosine – guanine dinucleotide motifs, or CpG DNA, have been extensively utilized for their immunostimulatory activity through interaction with the pattern recognition receptor toll-like receptor 9 (TLR-9). We investigated how varying the length of CpG DNA attached to gold nanoparticle (AuNP) SNAs affects both cellular uptake of the SNA into RAW-Lucia cells and activation of TLR-9. The CpG sequences were modeled after the CpG1826 sequence and synthesized with decreasing length down to five nucleotides (nt). Cellular uptake will be assessed with inductively coupled plasma mass spectrometry (ICP-MS). Activation and uptake will be further assessed with a UV-vis immunostimulation assay. It is hypothesized that decreasing the length of CpG DNA will decrease AuNP SNA uptake and TLR9 activation. Determining how length and sequence of CpG DNA impacts SNA uptake and immune activation can better inform strategic SNA structure design.