Regulating Nucleic Acid-based Self-assembly For Biological Analysis

Nucleic acid molecules have the characteristics of programmability and easy modification.They can be used to construct various complex static and dynamic assembly systems,and can be used to control the tissue state of substances to achieve new functions.Existing nucleic acid assembly systems are mainly constructed by precoding assembly,and the intermediate assembly path is usually difficult to control.In response to this problem,we designed a switch-stem-loop structure based on conformational transformation,combined with dynamic DNA strand replacement reaction,through the stem The transformation of the ring structure realizes the layered and step-by-step regulation of the nanostructure self-assembly path.Since the sequence in the stem-loop switch is arbitrary,it provides a universal and effective method for the self-assembly process of the modular and constant temperature control DNA structure.On this basis,we anchored the designed stem-loop switch to the surface of the cell membrane,and regulated the assembly between immune cells NK cells,leukemia cells K562 and Jurkat cells through the role of the switch,giving NK cells the ability to selectively target leukemia cells,Doubling its killing capacity,enhancing its application potential in tumor immunotherapy,and also providing a feasible strategy for studying in vitro regulation of multicellular signaling networks and functions.In addition,we also constructed a nucleic acid-encoded nano-gold flower assembly probe to achieve ultra-sensitive,rapid,and quantitative detection of bacteria.The electrostatic enrichment is used to assemble the nano gold flower and the magnetic beads to achieve magnetic enrichment.When the target DNA appears,specific hybridization is used to assemble the nano gold flower,reducing the detection line to 5fM,and the entire detection process takes only 2 hours to complete.