Research On SERS Analysis Of Metal Ions And Bioactive Molecules Based On Nano-gold Biosensor Probes

With the improvement of the living standard of human society,heavy metals accumulating in the body and major diseases have become important factors threatening human life and health.The prevention of heavy metal ion poisoning and the achievement of early diagnosis and prognosis treatment of major diseases have become a major challenge across the ages.In this work,gold nanoparticles were combined with surface-enhanced Raman scattering(SERS)to construct a new type of nano-gold biosensor probe with high sensitivity and specificity,which realized the detection of heavy metal ions and tumor markers microRNA(miRNA)in vitro and in vivo,and further fluorescence and Raman capture imaging of miRNA in tumor cells.A logic gate platform with double input and single output was constructed to realize the output and treatment of silent gene.This paper includes the following three parts:(1)Combination with microfluidic technology and surface-enhanced Raman technology,we designed a SERS nano-gold biosensor probe based on DNAzyme for quantitative detection of lead and copper ions in samples,and constructed a new SERS-microfluidic platform for trace detection of heavy metal ions.In this method,microfluidic microchannels and microelectrodes were used as reaction vessels to reduce the amount of reagent and reaction time.The high background signal caused by the biological barcode probes can be removed by magnetic separation using MBs as the carrier.This method is simple,rapid,sensitive and has good selectivity,and has a broad application prospect in the field of heavy metal ion detection.(2)We designed a fluorescence-Raman dual spectral signal amplification strategy and detection method based on abso lute value coupling of signals.In the scheme,we constructed a three-helix dual-beacon scintillaton probe(DSTP),which combined fluorescence with SERS to achieve in situ tracing of the probe and real-time dual-spectrum imaging of miRNA in living cells.Moreover,the absolute value coupling method of SERS signals was used for quantitative detection of homogeneous solution and intracellular miRNA,which reduced the background interference and improved the sensitivity.This strategy provides a simple and effective sensing platform for sensitive detection and imaging analysis of low level biomarkers in vivo and living cel s.(3)Using the property of DNA structural tautomatism,we designed a target-induced oscillating DNA nano-probe and constructed a cellular imaging logic gate with two types of miRNAs as input,which can carry silent genes into cells to achieve the silencing treatment of cancer.In this method,a nano-complex probe based on oscillating DNA nano-machine was prepared and incubated into cells,and the target miRNAs initiated the DNA nano-machine,which then triggered a series of chain replacement reactions to achieve gene silencing therapy.This work takes intracellular miRNAs as the input signal,realizes the output of cellular imaging logic gate and the delivery of intracellular silent gene,and constructs a multi-functional DNA logic gate sensing platform,providing new methods and technologies for early diagnosis and prognosis treatment of diseases.