A biomimetic 3D DNA nanoplatform for enhanced capture and high-purity isolation of stem cell exosomes

Exosomes are uniformly sized vesicle-like bodies that cells secrete. Researchers now believe that exosomes can mediate various health and pathological processes. However, because the biophysical properties of exosomes are similar to those of other cell secretion products and biological fluids are rich and diverse, their separation and purification have always been challenging. Inspired by the adhesive domains in the tentacles of marine organisms that effectively capture and release mobile food particles, we have built a biomimetic 3D DNA nanoplatform. This platform not only captures exosomes efficiently but also allows for light-controlled exosome release. The surface of the 3D DNA nanoplatform can grow multivalent aptamers via rolling circle amplification. Aptamers fold into specific secondary structures that bind to CD63, a protein expressed on the surface of exosomes, enabling efficient exosome capture. As a photothermal reagent, the temperature of the DNA nanoplatform increases under near-infrared light irradiation, destroying the secondary structure of the CD63 aptamer and releasing the exosomes. Additionally, we have demonstrated that a 3D DNA nanoplatform with multivalent CD63 aptamer structures achieves more efficient and convenient stem cell exosome separation compared to ultracentrifugation. This strategy provides an efficient and high-purity way to capture and reversibly separate exosomes, and the separated ultrapure exosomes are used for enhancing wound healing by modulating migration and angiogenesis.