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Nucleic acids are considered as promising materials for developing exquisite nanostructures from one to three dimensions. The advances of DNA nanotechnology facilitate ingenious design of DNA nanostructures with diverse shapes and sizes. Especially, the algebraic topological framework nucleic acids (ATFNAs) are functional DNA nanostructures that engineer guest molecules (e. g., nucleic acids, proteins, small molecules, and nanoparticles) stoichiometrically and spatially. The intrinsic precise properties and tailorable functionalities of ATFNAs hold great promise for biological applications, such as cell recognition and immunotherapy. This Perspective highlights the concept and development of precisely assembled ATFNAs, and outlines the new frontiers and opportunities for exploiting the structural advantages of ATFNAs for biological applications. [ABSTRACT FROM AUTHOR]

Efficient biocatalytic cascade reactions play a crucial role in guiding intricate, specific and selective intracellular transformation processes. However, the catalytic activity of the enzyme cascade reaction in bulk solution was greatly impacted by the spatial morphology and inter‐enzyme distance. The programmability and addressability nature of framework nucleic acid (FNA) allows to be used as scaffold for immobilization and to direct the spatial arrangement of enzyme cascade molecules. Here, we used tetrahedral DNA framework (TDF) as nanorulers to assemble two enzymes for constructing a double‐enzyme complex, which significantly enhance the catalytic efficiency of sarcosine oxidase (SOx)/horseradish peroxidase (HRP) cascade system. We synthesized four types of TDF nanorulers capable of programming the lateral distance between enzymes from 5.67 nm to 12.33 nm. Enzymes were chemical modified by ssDNA while preserving most catalytic activity. Polyacrylamide gel electrophoresis (PAGE), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to verify the formation of double‐enzyme complex. Four types of double‐enzyme complexes with different enzyme distance were constructed, in which TDF26(SOx+HRP) exhibited the highest relative enzyme cascade catalytic activity, ~3.11‐fold of free‐state enzyme. Importantly, all the double‐enzyme complexes demonstrate a substantial improvement in enzyme cascade catalytic activity compared to free enzymes. [ABSTRACT FROM AUTHOR]

The precise arrangement of single entity is a crucial objective of nanoscience and holds great promise in various fields such as biology and material science. In this work, we develop a "DNA framework‐mediated geometric renormalization" (DFMGR) strategy to reassemble gold nanoparticles into specific geometric shapes on a 2‐dimensional (2D) fluidic membrane interface. Cholesterol‐modified AuNPs are randomly anchored on the supported lipid bilayer (SLB) via the cholesterol‐lipid interaction. We demonstrate that AuNPs are laterally mobile on SLB and could be further rearranged into a specific geometric shape by DNA framework containing algebraically topological DNA arms. Using scanning electron microscope (SEM) imaging approach, simple geometric shapes, such as points assembled by monomers, line segments assembled by dimers, triangles assembled by trimers are visually presented. Interestingly, we found that the statistic angle (58.77°) and side length (12.21 nm) of triangles obtained from SEM images were both agreed well with the theoretical angle of 60° and side length of 12.58 nm. And the relative error of the angle calculated was as low as 0.33 %. These results indicated that the DFMGR strategy showed precise regulation ability for the AuNPs renormalization. We believe that DNA framework‐mediated geometric renormalization strategy would be a powerful means for regulating ligand‐receptor interactions in biosystems and for nanoparticle assembling in material science. [ABSTRACT FROM AUTHOR]

Highly efficient transmembrane transport of exogenous reagents into cells is of vital importance for developing drug‐delivery systems. Conventionally, transmembrane transport of exogenous reagents was accomplished with the assistance of transfection agents or other artificial means. However, the high toxicity and low transport efficiency of current delivery techniques still remain to be solved. In this work, by anchoring artificial receptors onto cell membranes with a mild chemical reaction, we demonstrated that the exogenous reagent framework nucleic acids, namely tetrahedral DNA nanostructures (TDN) can bind onto cell membranes effectively by the hybridization between single‐stranded DNA (ssDNA) and pendant ssDNA of TDN. The transport rate was greatly enhanced, with the endocytosis time could be as fast as 0.5 h. Furthermore, the transport quantity was prominently improved, with around 30 % of TDN endocytosed within 4 h. Owing to its rapid transmembrane transport speed and improved endocytosis quantity, this artificial‐receptor‐mediated transmembrane transport is a promising tool for achieving rapid and highly efficient transmembrane transport of exogenous reagents. [ABSTRACT FROM AUTHOR]