DNA Triangular Prisms On Microbeads For Multitarget Detection And Immobilization Of Cascade Enzyme

DNA nanostructures,as a new functional soft material,due to their unique properties such as sequence controllable hybridization,convenient programming design,intelligent reversible response,and good biocompatibility,have attracted much attention and been extensively studied in the field of biosensing,cell imaging,protein immobilization,nano-machine and so on.With the gradual development of DNA nanotechnology,researchers have desigened and constructed a variety of different functional DNA nanostructures,such as triangular prisms,tetrahedrons,polyhedrons,and other specific geometrical nanostructures,or nano-boxes,nanotubes,Nano-vase and other high-end structure.Here,we constructed the DNA triangular prism(TP)nanostructures,and exploited their applications in the field of multi-target biomolecule detection and immobilization of cascade enzyme.The details are summarized as follows:1.Design of a modular DNA triangular-prism sensor enabling ratiometric and multiplexed biomolecule detection on a single microbead.We integrated multiple sensing modules into a single DNA three-dimensional nanoarchitecture with a TP structure for ratiometric and multiplexed biomolecule detection on a single microbead.In our design,the complementary hybridization of three clip sequences formed TP nanoassemblies in which the six single-strand regions in the top and bottom faces act as binding sites for different sensing modules,including an anchor module,reference sequence module,and capture sequence module.The multifunctional modular TP nanostructures were thus exploited for ratiometric and multiplexed biomolecule detection on microbeads.Microbead imaging demonstrated that,after ratiometric self-calibration analysis,the imaging deviations resulting from uneven fluorescence intensity distribution and differing probe concentrations were greatly reduced.The rigid nanostructure also conferred the TP as a framework for geometric positioning of different capture sequences.The inclusion of multiple targets led to the formation of sandwich hybridization structures that gave a readily detectable optical response at different fluorescence channels and distinct fingerprint-like pattern arrays.This approach allowed us to discriminate multiplexed biomolecule targets in a simple and efficient fashion.In this module-designed strategy,the diversity of the controlled DNA assembly coupled with the geometrically well-defined rigid nanostructures of the TP assembly provides a flexible and reliable biosensing approach that shows great promise for biomedical applications.2.Immobilization of cascade enzyme on DNA triangular-prism framework enabling efficient catalytical production of nitric oxide(NO)on a single microbead.Based on the multi-binding sites of the DNA nanostructure TP,Glucose oxidase(GOx)and horseradish peroxidase(HRP)were coassembled onto the DNA triangular prism to form the enzyme loaded TP nanostructure.Through the H2O2-ABTS colormetric analysis,it was found that the DNA nanostructure promoted the catalytic activity of the cascade enzyme compared to that of GOx/HRP pair without the DNA nanostructure.Furthermore,the cascade enzyme were immobilized on the microspheres mediated by the TP nanostructures,and in the presence of the substrates of glucose and hydroxyurea,led to the efficient production of the biological messenger nitric oxide.Nitric oxide plays an important role in the life of the mammal,and acts as a signal molecule.The catalytic reaction provides a good reference for biomimetic catalysis,and this work also showed a convenient approach to the immobilization of cascade enzyme.