High Sensitivity Detection And Logic Gate Sensing Based On SERS And DNA Reactions

In this paper,a nucleic acid amplification strategy was developed to construct a surface-enhanced Raman scattering technique to achieve miRNA high sensitivity detection and logic gates sensing.The SERS combined with extended branch hybridization chain reaction(EB-HCR)and Rolling-Circle DNA signal amplification to achieve the desired detection results.The main research includes the following two aspects:1.Firstly,Extended Branching Hybridization Chain Reaction(EB-HCR)was designed based on classical HCR and hyper-branching HCR,with the aim of providing more branches;and miRNA was detected with high sensitivity and specificity through an assay that featured the combination of EB-HCR and the surface-enhanced Raman scattering(SERS)based on an enhancing matrix.The previously reported HCRs were extended,so that more branching occurred in each round of growth in the assembling of the product;combined with SERS technology,the signal was enhanced,resulting in increased sensitivity.A transduction and signal amplification step was also incorporated into the system to deal with the issues rising from the nature of target DNA including instability and low content.The three components were interlinked through a “messenger” DNA;it is produced as the product of the transduction step,and then served as a linker for the EB-HCR amplification and SERS enhancement.Enhanced sensitivity was obtained,with the good detection limitation.Also,sufficient specificity to distinguish between target DNA with similar sequences was testified.2.Secondly,a proof-of-principle logic system was established with the aim of identifying the tissue origins of the cancer,in the light of their established relationship with the miRNA distributions.The system did this by detecting the two characteristic miRNA sets from a pool with two gates,each identifying the set of three input miRNAs,with miRNAs members shared among the two sets.The system centred on the logic judgement,which was implemented with multi-input and multi-output logic gate complex;signal amplification was also incorporated,providing the system with the practical capacity and efficiency to deal with miRNA pool.It was verified this system successfully addresses the multiple-input and multiple-output logic relationship of miRNA distribution and the cancer origin;at the same time,other concerns from the nature of miRNA,such as low concentration and instability,can also be dealt with.