Molecular Recognition-Based DNA Nanoassemblies on the Surfaces of Nanosized Exosomes

Abstract

Exosomes are membrane-enclosed extracellular vesicles derived from cells, carrying biomolecules that include proteins and nucleic acids for intercellular communication. Owning to their advantages of size, structure, stability, and biocompatibility, exosomes have been used widely as natural nanocarriers for intracellular delivery of theranostic agents. Meanwhile, surface modifications needed to endow exosomes with additional functionalities remain challenging by their small size and the complexity of their membrane surfaces. Current methods have used genetic engineering and chemical conjugation, but these strategies require complex manipulations and have only limited applications. Herein, we present an aptamer-based DNA nanoassemblies on exosome surfaces. This in situ assembly method is based on molecular recognition between DNA aptamers and their exosome surface markers, as well as DNA hybridization chain reaction initiated by an aptamer-chimeric trigger. It further demonstrated selective assembly on target cell-derived exosomes, but not exosomes derived from nontarget cells. The present work shows that DNA nanostructures can successfully be assembled on a nanosized organelle. This approach is useful for exosome modification and functionalization, which is expected to have broad biomedical and bioanalytical applications.

Homogeneous, Low‐volume, Efficient, and Sensitive Quantitation of Circulating Exosomal PD‐L1 for Cancer Diagnosis and Immunotherapy Response Prediction

“…For flow cytometry (FCM) and confocal imaging,the exosomes were adsorbed on aldehyde latex microspheres. [19] Thes ignal of CD63 (a common exosomal biomarker) was obvious ( Figure S7), indicating that exosomes were successfully modified onto the microspheres.F or exosomal PD-L1 recognition, the fluorescence enhancement of the MJ5C aptamer binding (compared to control sequence) was about 5t imes higher than that of the antibody (compared to control protein;F igure 3D), and MJ5C maintained high selectivity and demonstrated no observable binding against PD-L1 negative exosomes ( Figure 3E). Furthermore,c onfocal results indicated that some fluorescent spots were distributed on the surface of the PD-L1 positive microspheres,w hich came from the binding of the fluorescent labeled aptamer ( Figure 3D).…”

Exosomes: Isolation, Analysis, and Applications in Cancer Detection and Therapy

“…The Tan group, for example, developed a sensor for electrochemical detection of cancerous exosomes . In that work, they introduced a aptamer, named LZH8, that could specifically recognize HepG2 (hepatocarcinoma cells) and their exosomes . As shown in Figure , aptamer LZH8 was attached to a DNA nanotetrahedron (NTH).…”

“…[59] In that work, they introduced aa ptamer,n amed LZH8,t hat could specifically recognize HepG2 (hepatocarcinoma cells) andt heir exosomes. [60] As shown in Figure 5, aptamer LZH8 was attached to aD NA nanotetrahedron (NTH). Subsequently,t he NTH sequences werei mmobilizedo ntot he surfaces of Au electrodes.…”

In Situ Amplification‐Based Imaging of RNA in Living Cells

“…[44,52,[62][63][64] 3. Non-enzymatic and Isothermal Signal Amplification Techniques Dynamic DNAs elf-assembly (DDSA) is fueled by the free energy of hybridization between metastable DNAh airpins or driven by the entropy of hybridization between linear DNAm olecules, [63,[65][66][67][68][69][70][71][72][73] and can operate in an autonomous and reconfigurable manner.F or instance,t he hybridization chain reaction (HCR) was first proposed by the Pierce group in 2004 ( Figure 1A). [63] Tw om etastable DNAh airpin monomers coexist in solution, only upon exposure to an initiator nucleic acid fragment, HCR is triggered and the monomers sequentially assemble to form al ong double-stranded DNA analogue with nicking sites.S ubsequently,t hey developed anew DDSA technique,which they termed catalyzed hairpin assembly (CHA) or catalytic assembly circuit (CAC) ( Figure 1B).…”