Ultra-sensitive Detection Of Tumor Markers Based On Locked Nucleic Acid Functionalized Biosensors

With the in-depth study of materials by researchers,nanomaterials have entered the field of vision.Research on nanomaterials is now getting deeper and deeper,and it has been moved into research in various fields.Metal nanomaterials are superior in sensing properties,such as excellent electrical conductivity,good biocompatibility,and high catalytic activity,especially noble metal ions such as nano-platinum have superior catalytic activity to hydrogen peroxide,and are being researched by more and more researchers.Used in the construction of biosensors.In this paper,with the help of Raman spectroscopy,electrochemical detection,fluorescence inverted microscope and other techniques,the surface-enhanced Raman effect of the 3D nano-organic framework and the coaxial biosensor are formed by the rolling circle replication amplification signal and the specific recognition of the locked nucleic acid.Targeted recognition and detection of tumor markers such as Let-7a and circulating tumor DNA were performed in other ways.1.Ultrasensitive SERS detection of highly homologous miRNAs by generating 3D organic-nanoclusters and a functionalized chip with locked nucleic acid probesHerein,a new finding is reported that 3D organic-nanoclusters(3DONs)with superior SERS properties as an original reporter could accurately and sensitively distinguish microRNAs(miRNAs)with highly similar sequences,even with a single-nucleotide difference,as a result of a functionalized chip with locked nucleic acid probes(LNAP-chip)and rolling circle replication(RCA).Furthermore,the innovative SERS-method could be used to broadly discriminate cancer cells from normal cells and evaluate changes in the expression levels of intracellular miRNAs2.Coaxial Sensing Bio-amplifier for Ultrasensitive Detections of Circulating Tumor DNAWe herein report the first attempt to engineer a coaxial-sensing 3D amplifier able to achieve dynamic selfassembly in response to a specific intracellular the mutated-ctDNA target.A bio-nanofiber is firstly manufactured via an ingenious double-channel electrostatic spinning and nucleic acid technology,which offered an ideal scaffold for assembly of 3D amplifier activated by target recognition.The coaxial-controllable signal amplifier presented several advantages.(1)Given its “coaxial sensing effect”,the proposed bio-amplifier played the coaxial transduction for signal enrichment to vastly increase sensitivity,capable of discriminating a single-base mismatched sequence from the perfectly complementary one,using ctDNA-134 A as a model analyte.(2)Due to “covalent bridges lock effect” in an identifying chip with locked nucleic acid beacons,this 3D amplifier expressed high specificity and biostability toward seven different mutated-ctDNAs.(3)Profiting from special configuration of bioactive nanofibers and DNA replication programming,this catalytic bio-amplifier possessed “signal enrichment effect”,which enhanced dynamic range toward ctDNA-134 A detection and hybridized without any external indicators.This pioneered method was further applied for broadly differentiate cells and evaluate changes in the expression levels of intracellular mutated-ctDNAs.