Effects of Oligolysine-Polyethylene Glycol Coating on the Biodistribution of Wireframe DNA Origami Nanosheets in Zebrafish Embryos

DNA origami-based nanotechnology is a versatile tool
for exploring
fundamental biological questions and holds significant promise for
future biomedical applications. Here, we leverage the optical transparency
of the embryonic zebrafish to analyze live embryos injected intravenously
with fluorescently labeled wireframe DNA origami nanosheets. Our approach
integrated long-term, high-resolution imaging of transgenic live zebrafish
embryos with single-cell RNA sequencing to elucidate the effects of
oligolysine-polyethylene glycol copolymer (K-PEG) coating on the biodistribution
of fluorescence signal in embryos injected with wireframe DNA origami
nanosheets. We observed rapid accumulation of fluorescence signal
in the caudal hematopoietic tissue (CHT). K-PEG coating mitigated
the accumulation of fluorescence signal in CHT, enabling increased
detection of signal in other tissues. Our findings highlighted the
pivotal role of scavenger endothelial cells in DNA origami clearance,
with K-PEG enabling the prolonged detection of fluorescence signal
at the CHT. Furthermore, using a transgenic zebrafish line designed
for targeted macrophage ablation, we found that macrophages contribute
to the clearance of fluorescence signal in embryos injected with the
noncoated but not with K-PEG-coated nanosheets. This study introduces
a framework for the analyses of the biodistribution and clearance
of DNA origami nanostructures in vivo with single-cell
resolution in zebrafish models.