Self-Assembly of Multivalent Aptamer-Tethered DNA Monolayers Dedicated to a Fluorescence Polarization-Responsive Circular Isothermal Strand Displacement Amplification for Salmonella Assay

Abstract

Pathogenic bacteria are pathogens widely spread that are capable of causing mild to life-threatening diseases in human beings or other organisms. Rationally organizing the simple helical motif of double-stranded DNA (dsDNA) tiles into designed ensemble structures with architecturally defined collective properties could lead to promising biosensing applications for pathogen detection. In this work, we facilely engineered multivalent hairpin aptamer probe-tethered DNA monolayers (MHAP-DNA monolayers) and applied them to build a fluorescence polarization-responsive circular isothermal strand displacement amplification (FP-CSDA) for Salmonella assay. In this system, the MHAP-DNA monolayers were constructed based on a dsDNA tile-directed selfassembly. A FAM-labeled reporting probe (RP FAM ) with an inherent low FP signal serves as the signaling unit. The presence of target Salmonella leads to the trapping of F RP FAM into the super DNA monolayers via a target-triggered CSDA to peel off the tethered hairpin-structured aptamer probes (HAPs) responsible for the binding of RP FAM . As a result, the FP signal of the FAM fluorophore can be remarkably amplified due to the recycling of target Salmonella and the capacity of structural DNA materials to strongly restrict the free rotation of the FAM fluorophore but without a fluorescence quenching effect. Experimental results demonstrate that the FP assay is able to detect Salmonella with a low limit of detection (LOD) of 7.2 × 10 0 CFU/mL and high specificity. As a proof-ofconcept study, we envision our study using DNA nanoarchitecture as the foundation to modulate CSDA-based FP assays, promising to open up a new avenue for disease diagnosis, food safety detection, and biochemical studies.

The Compact Integration of Multiple Exonuclease III-Assisted Cyclic Amplification Units for High-Efficiency Ratiometric Electrochemiluminescence Detection of MRSA

“…Bacteria have posed a significant threat to the public health security of human society throughout their development. , With the overuse of antibiotics, antibiotic-resistant bacteria have emerged that can even decompose and actively eliminate drugs, posing a significant challenge to the clinical treatment of these pathogens. , Among them, methicillin-resistant Staphylococcus aureus (MRSA) exhibits multiresistance to a plethora of antibiotics, rendering the treatment of MRSA infection as one of the most complex dilemmas. , The conventional techniques for bacterial detection, such as culture counting and PCR, often necessitate prolonged incubation periods and the use of sophisticated equipment, thereby imposing limitations on their clinical applicability . Therefore, the development of reliable MRSA detection methods is essential for the timely implementation of effective infection control measures.…”

An intelligent readable and capture-antibody-independent lateral flow immunoassay based on Cu2−xSe nanocrystals for point-of-care detection of Escherichia coli O157:H7

“…3 Traditional bacterial diagnosis methods mainly include colony culture and genotyping, which are time-consuming and not suitable for portable detection of E. coli O157: H7. 4 At present, some biosensors have been developed to provide new methods for bacterial detection, including the fluorescence method, [5][6][7][8] the surface-enhanced Raman scattering method, 9 and the electrochemical method. 10 Despite obtaining good sensitivity and specificity, the above methods still require expensive instruments and professional operating techniques, complex material modifications, and high costs, which are not conducive to the real-time detection of pathogens.…”

Intramolecular Accelerated Assembly of Molecular Beacons: A DNA Nanoarchitecture-based Spatial Confinement Strategy toward Terminal Deoxynucleotidyl Transferase Biosensing

“…Fortunately, in addition to wide-known critical biological roles of deoxyribonucleic acid (DNA) to act as a central genetic biomolecule in living systems, the highly programmable, predictable, and controllable Watson–Crick base pairing of DNA has shown usefulness as a specific material for the exploration of virtually any DNA nanostructure. − Compared with common inorganic nanoparticles, DNA nanomaterials have shown great design flexibility, synthesis simplicity, low batch difference, and high uniformity. Most importantly, due to its unique characteristics of high programmability and addressability, DNA nanomaterials have provided an ideal scaffold for spatial-confinement study via site-specific confining diverse reactants in a compact space. − This spatially confined environment allows the change of routine “intermolecular” reaction into “intramolecular” reaction using DNA nanostructures as reaction carriers to maintain a high local effective concentration of reactants, enhance mass transportation, and in turn accelerate reaction.…”