Fast and specific enrichment of cancer-related exosomes by DNA-nanoweight-assisted centrifugation

Exosomes are nanoscale membrane vesicles actively released by cells and play an important role in the diagnosis of cancer-related diseases. However, it is challenging to efficiently enrich exosomes from extracellular fluids. In this work, we used DNA-tetrahedron as a nanoweight during centrifugation to precisely enrich tumor exosomes from a complex biological environment. Two different DNA tetrahedral nanostructures (DTAs), each carrying a specific aptamer for exosome biomarker recognition, were incubated with clinical samples simultaneously. One DTA triggered the cross-linking of multiple target exosomes, and therefore enabled low-speed and fast centrifugation for enrichment. The other DTA further narrowed down the target exosome subtype and initiated a hybridization chain reaction (HCR) for sensitive signal amplification. The method enabled the detection of 180 MCF-7-derived exosomes per microliter and 560 HepG2-derived exosomes per microliter, with 1000-fold higher sensitivity than conventional ELISA. This easy-to-operate method can enrich exosomes with excellent specificity and therefore will be appealing in biomedical research and clinical diagnosis.

The Application of Tetrahedral Framework Nucleic Acids as a Drug Carrier in Biomedicine Fields

In recent years, tetrahedral Framework Nucleic Acids(tFNAs) have become a hot topic in the field of DNA nanostructures because of their stable structures, nanoscale size, superior mechanical properties and convenient synthesis with high yield. tFNAs are considered promising drug delivery carriers because they can pass through the cellular membrane without any help and they have a good biocompatibility and biodegradability. Besides, they have rich modification sites, they can be modified by kinds of functional groups. The functionalization molecules can be modified on the vertexes, embedded between the double-stranded DNA of the tetrahedron edges, hanged on the edges, or encapsulated in the cage-like structure of the tetrahedron. The structure of tetrahedron can also be intelligently controlled through smart design, such as integrating DNA hairpin loop structure onto the edges. Nowadays, DNA tetrahedron will have a broader development prospect in the application of drug transport carriers and intelligent drug carriers. Therefore, DNA material is a new carrier material with great advantages and has a very broad application prospect in the construction of an intelligent drug transport system.