Graphical Abstract

Metastasis portends a poor prognosis for cancer patients. Primary tumor cells disseminate through the bloodstream before the appearance of detectable metastatic lesions. The analysis of cancer cells in blood-so-called circulating tumor cells (CTCs)-may provide unprecedented opportunities for metastatic risk assessment and investigation. NanoFlares are nanoconstructs that enable livecell detection of intracellular mRNA. NanoFlares, when coupled with flow cytometry, can be used to fluorescently detect genetic markers of CTCs in the context of whole blood. They allow one to detect as few as 100 live cancer cells per mL of blood and subsequently culture those cells. This technique can also be used to detect CTCs in a murine model of metastatic breast cancer. As such, NanoFlares provide, to our knowledge, the first genetic-based approach for detecting, isolating, and characterizing live cancer cells from blood and may provide new opportunities for cancer diagnosis, prognosis, and personalized therapy.cancer metastasis | nanotechnology | diagnostic | mRNA | NanoFlares

The effect of serum protein adsorption on the biological fate of Spherical Nucleic Acids (SNAs) is investigated. Through a proteomic analysis, it is shown that G-quadruplexes templated on the surface of a gold nanoparticle in the form of SNAs mediate the formation of a protein corona that is rich in complement proteins relative to SNAs composed of poly-thymine (poly-T) DNA. Cellular uptake studies show that complement receptors on macrophage cells recognize the SNA protein corona, facilitating their internalization, and causing G-rich SNAs to accumulate in the liver and spleen more than poly-T SNAs in vivo. These results support the conclusion that nucleic acid sequence and architecture can mediate nanoparticle—biomolecule interactions and alter their cellular uptake and biodistribution properties and illustrate that nucleic acid sequence is an important parameter in the design of SNA therapeutics.

To understand the effect of three-dimensional oligonucleotide structure on protein corona formation, we studied the identity and quantity of human serum proteins that bind to spherical nucleic acid (SNA) nanoparticle conjugates. SNAs exhibit cellular uptake properties that are remarkably different from those of linear nucleic acids, which have been related to their interaction with certain classes of proteins. Through a proteomic analysis, this work shows that the protein binding properties of SNAs are sequence-specific and supports the conclusion that the oligonucleotide tertiary structure can significantly alter the chemical composition of the SNA protein corona. This knowledge will impact our understanding of how nucleic acid-based nanostructures, and SNAs in particular, function in complex biological milieu.

Ribonucleic acids (RNAs) are key components in many cellular processes such as cell division, differentiation, growth, aging, and death. RNA spherical nucleic acids (RNA-SNAs), which consist of dense shells of double-stranded RNA on nanoparticle surfaces, are powerful and promising therapeutic modalities because they confer advantages over linear RNA such as high cellular uptake and enhanced stability. Due to their three-dimensional shell of oligonucleotides, SNAs, in comparison to linear nucleic acids, interact with the biological environment in unique ways. Herein, the modularity of the RNA-SNA is used to systematically study structure–function relationships in order to understand how the oligonucleotide shell affects interactions with a specific type of biological environment, namely, one that contains serum nucleases. We use a combination of experiment and theory to determine the key architectural properties (i.e., sequence, density, spacer moiety, and backfill molecule) that affect how RNA-SNAs interact with serum nucleases. These data establish a set of design parameters for SNA architectures that are optimized in terms of stability.