The self-replication of information is a key feature of nature, and the development of self-replication systems is of great significance to the study of the origin of life. Inspired by the natural replication process of DNA in biological systems, researchers have reported some artificial DNA nanostructures that can achieve self-replication. However, it is a challenging problem to further construct complex synthetic systems that can produce large-scale three-dimensional ordered nanomaterials using self-replicating DNA nanostructures.
In view of this, Yao Dongbao, a special associate researcher in the research group of Professor Liang Haojun (deceased) of the Department of Polymer Science and Engineering of the University of Science and Technology of China, and others imitated the replication and assembly process of molecules in nature, and used the programmable DNA strand substitution network to regulate the assembly path of nanoparticles, and constructed a self-replication system that can realize the self-replication of nanoparticles and the precise assembly of three-dimensional superlattice structures. The results were recently published online in the international academic journal Angewandte Chemie, titled "Programming of Supercrystals Using Replicable DNA-Functionalized Colloids".
In recent years, great progress has been made in the bottom-up synthesis of three-dimensional ordered nanolattice materials in the field of DNA functionalized gold nanoparticles (DNA-AuNPs) assembly. Because DNA-AuNPs have both the optical properties of the inner body of inorganic nanoparticles and the biological properties and programmability of the outer DNA, they are regarded as programmable atom equivalents (PAEs). PAEs can be assembled by non-covalent linkages ("DNA bonds") formed by interactions between superficial sticky ends, and ordered three-dimensional superlattices can be formed by thermal annealing or thermostatic DNA induction network regulation. Therefore, PAEs are ideal primitives for the construction of self-replicating nanoassembly systems capable of generating three-dimensional ordered superlattices.
Figure 1. Schematic diagram of DNA strand substitution inducing assembly network regulating PAE seed replication and replicator assembly. Based on the progress made by our group in the field of PAE superlattice thermostatic induced assembly (PNAS 2020, 117, 5617; PNAS 2023, 120, e2219034120), the authors constructed a self-replication system that can realize PAE replication and superlattice assembly by accurately designing a programmable DNA strand substitution urging assembly network to regulate the PAE assembly path (Fig. 1). The system consists of a template system containing inactive PAE seeds and triggers, and a propulsion assembly system containing inactive PAE replicas and fuel chains. Among them, the trigger chain and the fuel chain Fuel end carry replication information (sticky end sequence). The addition of the initiator strand to the reaction system can bind to the surface reaction site (toehold) of the inactive PAE seed, and then the DNA strand replacement reaction occurs, so that it can be transformed into an active seed carrying a sticky end, and the hyocalyptic agent Catassembler is released. Through the precise regulation of the programmable DNA induction assembly network, the same sticky ends as those on the surface of PAE seeds can be gradually generated on the surface of a large number of inactive PAE replicates, so as to realize the replication and amplification of PAE seeds, and the PAE replicators can be further assembled to form an orderly superlattice. By adjusting the molar ratio of PAE seed to replicator, the replication efficiency of PAE template and the crystal quality of the superlattice can be effectively controlled. In addition, the authors demonstrated the unique ability of the PAE replication system to accurately identify the correctness of the delivery of template system information (Catassembler) during the reaction (Figure 2).
Figure 2. Small-angle X-ray scattering and SEM characterization of a one-component PAE self-replication system regulated by DNA strand substitution inducing assembly network. Based on this PAE self-replication strategy, the authors further constructed a two-component PAE self-replication system that can form body-centered cubic and cesium chloride superlattices. By replacing the core of PAE with gold nanoparticles and active proteases, the authors achieved replication amplification of protease PAEs and construction of protease superlattices (Fig. 3). In addition, by using a small amount of PAE superlattice as the initial replication template, the authors realized the control of the phase transition between PAE superlattices with different crystal symmetries and the amplification of the superlattice structure formed after the transition. The DNA induction assembly network to regulate PAE replication and 3D superlattice construction strategies reported in this work not only successfully mimic the replication and assembly processes of molecules in nature, but also take an important step towards the fabrication of complex programmable self-replicating large-scale 3D colloidal superlattice materials.
Figure 3. A two-component PAE self-replication system with protease as the core. Xiaoyun Sun, a Ph.D. student in the research group of Professor Haojun Liang (deceased) at the University of Science and Technology of China, and Associate Researcher Hua Wenqiang from Shanghai Light Source are the co-first authors of this paper, and Yao Dongbao, a special associate researcher at the University of Science and Technology of China, is the corresponding author of this paper. This work was supported by the National Natural Science Foundation of China, the Hefei National Research Center for Physical Sciences at the Microscale, and the University of Science and Technology of China. https://onlinelibrary.wiley.com/doi/10.1002/anie.202403492 Source: Frontiers of Polymer Science