Study On Functionalized Nucleic Acid Origami For Detection Of Bioactive Molecules

Based on the fluorescence,UV absorption and laser scanning confocal microscopy,this paper uses functional nucleic acid folding technology and colorimetric amplification method based on hybridization chain reaction for combined administration of cells,targeted therapy and detection of mi RNA and ATP.The main contents of this paper are as follows:(1)Diagnosis–Therapy Integrative Systems based on Magnetic RNA Nanoflowers for Co-drug Delivery and Targeted Therapy.This study was to develop a co-drug delivery system for targeting cancer therapy based on magnetic RNA nanoflowers(RNA NF).Compared with traditional nucleic acid structure,convenient separation can be achieved by introducing magnetic nanoparticle(MNP)into RNA NF.Folic acid(FA)modified MNP/RNA NF(FA/MNP/RNA NF)was used as a targeting nanocarrier with excellent biocompatibility to overcome the nonselectivity of MNP/RNA NF.And then,anticancer drug doxorubicin(DOX)and photosensitizer 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin(TMPyP4)binding with RNA NF were used as co-drug cargo models.RNA NF was first used for co-drug delivery.So,imaging fluorescent tags,target recognition element,and drug molecules were all assembled together on the surface of MNP/RNA NF.The experimental results suggested that the treatment efficacy of co-drug delivery platform(FA/MNP/RNA NF/D/T)was better than single-drug delivery platform(FA/MNP/RNA NF/D).Besides,the FA/MNP/RNA NF was used as a probe for cancer cell detection.The limit of detection was 500 cell/mL.In conclusion,the co-drug delivery platform based on FA/MNP/RNA NF was a promising approach for the intracellular quantification of other biomolecules,as well as a diagnosis–therapy integrative system.(2)A universal amplified-colorimetry for nucleic acids and aptamer-specific ligands detection based on hybridization chain reaction.We present a universal amplified-colorimetric for detecting nucleic acid targets or aptamer-specific ligand targets based on gold nanoparticle-DNA(GNP-DNA)hybridization chain reaction(HCR).The universal arrays consisted of capture probe and hairpin DNA-GNP.First,capture probe recognized target specificity and released the initiator sequence.Then dispersed hairpin DNA modified GNPs were cross-linked to form aggregates through HCR events triggered by initiator sequence.As the aggregates accumulate,a significant red-to purple color change can be easily visualized by the naked eye.We used miRNA target sequence(miRNA-203)and aptamer-specific ligand(ATP)as target molecules for this proof-of-concept experiment.Initiator sequence(DNA 2)was released from the capture probe(MNP/DNA1/2 conjugates)under the strong competitiveness of miRNA-203.Hairpin DNA(H 1 and H 2)can be complementary with the help of initiator DNA 2 to form GNP-H1/GNP-H2 aggregates.The absorption ratio(A620/A520)values of solutions were a sesitive function of miRNA-203 concentration covering from 1.0×10-11 M to 3.0×10-10 M,and as low as 1.0×10-11 M could be detected.At the same time,the color changed from light wine red to purple and then to light blue have occurred in the solution.For ATP,initiator sequence(5'-end of DNA 3)was released from the capture probe(DNA 3)under the strong combination of aptamer-ATP.The present colorimetric for specific detection of ATP exhibited good sensitivity and 1.0×10-8M ATP could be detected.The proposed strategy also showed good performances for qualitative analysis and quantitative analysis of intracellular nucleic acids and aptamer-specific ligands.