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Dynamic regulation of DNA origami nanostructures is important for the fabrication of intelligent DNA nanodevices. Toehold-mediated strand displacement is a common regulation strategy, which utilizes trigger strands to assemble and disassemble nanostructures. Such trigger strands are required to be completely complementary to the corresponding substrate strands, which strictly demands orthogonality and accuracy of the sequence design. Herein, we present a disassembly strategy of DNA origami dimers based on polymerase-triggered strand displacement, where the polymerase primers, as the trigger strands, were only partially complementary to the toehold region of the substrate strands. To demonstrate the programmability of trigger strands, we utilized primers with different sequence combination patterns to disassemble DNA origami dimers. The statistical summary of AFM images and fluorescence curves proved the feasibility of the new strategy. The utilization of polymerase-triggered strand displacement on the disassembly of DNA origami structures enriches the toolbox for the dynamic regulation of DNA nanostructures.

In the framework of Membrane Computing, several efficient solutions to computationally hard problems have been given. To find new borderlines between families of P systems that can solve them and the ones that cannot is an important task to tackle the P versus NP problem. Adding syntactic and/or semantic ingredients can mean passing from non-efficiency to presumed efficiency. Here, we try to get narrow frontiers, setting the stage to adapt efficient solutions from a family of P systems to another one. In order to do that, a solution to the problem is given by means of a family of tissue P systems with evolutional symport/antiport rules and cell separation with the restriction that both the left-hand side and the right-hand side of the rules have at most two objects; that is, with recognizer P systems from $${\mathcal {TSEC}}(2, 2)$$ TSEC ( 2 , 2 ) . This result improves a previous one, when 3 objects could be used in the left-hand side of the evolutional communication rules

The precursors of functional biomolecules in living cells are synthesized in a bottom-up manner and subsequently activated by modification into a delicate structure with near-atomic precision. DNA origami technology provides a promising way to mimic the synthesis of precursors, although mimicking the modification process is a challenge. Herein, a DNA paper-cutting (DNA kirigami) method to trim origami into designer nanostructures is proposed, where the modification is implemented by a polymerase-triggered DNA strand displacement reaction. Six geometric shapes are created by cutting rectangular DNA origami. Gel electrophoresis and atomic force microscopy results demonstrate the feasibility and capability of the DNA paper-cutting method. The proposed DNA paper-cutting strategy can enrich the toolbox for dynamically transforming DNA origami and has potential applications in biomimetics. .

It is widely observed that life activities are regulated through conformational transitions of biological macromolecules, which inspires the construction of environmental responsive nanomachines in recent years. Here we present a thermal responsive DNA origami dimers system, whose conformations can be cyclically switched by thermal cycling. In our strategy, origami dimers are assembled at high temperatures and disassembled at low temperatures, which is different from the conventional strategy of breaking nanostructures using high temperatures. The advantage of this strategy is that the dimers system can be repeatedly operated without significant performance degradation, compared to traditional strategies such as conformational transitions via i-motif and G-quadruplexes, whose performance degrades with sample dilution due to repeated addition of trigger solutions. The cyclic conformational transitions of the dimers system are verified by fluorescence curves and AFM images. This research offered a new way to construct cyclic transformational nanodevices, such as reusable nanomedicine delivery systems or nanorobots with long service lifetimes.

Maximally parallel manner is a usual rule application strategy for P systems, where rules should be used in parallel to the maximum degree possible. In this work, we consider a rule application strategy, rule synchronization, where some synchronization sets of rules are given, a rule in a synchronization set of rules can be applied only if all rules in the set are enabled. Tissue P systems with synchronized symport/antiport rules and synchronization sets of rules are called tissue P systems with synchronized symport/antiport rules. We prove that tissue P systems with synchronized symport/antiport rules consisting of only one cell are universal. Besides, we prove that the SAT problem can be solved by the proposed tissue P systems when cell division rules are introduced. The results show that synchronization over rules is a rule application strategy that can increase the computational power of tissue P systems with symport/antiport rules.