Construction Of Sensing System Based On Nucleic Acid Probe And Quantum Dots For Detection Of HPV DNA

A significant contributor to cervical cancer and other cancers is human papillomavirus(HPV)infection that persists over time.In clinical research,the quick and precise detection of high-risk HPV16 and HPV18 is crucial.As one of the most popular types of biosensors,using nucleic acid probes as identifiers has significant benefits for enhancing sensor specificity and sensitivity.Quantum dots(QDs)as fluorescent signals can fully satisfy the requirements for probes in biosensing owing to their distinctive adjustable photoluminescence characteristics and chemical inertness.In this paper,a quantum dot-nucleic acid probe biosensor was constructed for high sensitivity and specificity identification of HPV16 and HPV18.Here are the primary pieces of work:1.The nucleic acid probes were first designed using ssDNA and sunflower seed shells carbon quantum dots(SCQDs)to construct a fluorescent “off-on” platform for microanalysis of a single type of HPV16.Sunflower seed shells were employed as precursors,L-arginine was added,and polyethyleneimine(PEI)was used as a passivate to create positively charged,stable,and environmentally friendly biomassSCQDs.The fluorescence of manufactured SCQDs can be quenched by DNA probes modified with 4-(4-dimethylaminophenyl azo)benzoyl(Dabcyl),a fluorescence quenching agent,as a result of electrostatic forces and the F?rster resonance energy transfer(FRET)process.The HPV16 attached to the DNA probe activated the fluorescence of SCQDs by detaching the DNA probe from the SCQDs because it adhered to tight base complementary pairing regulations.This technique is crucial for biochemical analysis since it allows for the very precise detection of target sequences without the need for complicated procedures or expensive equipment.2.In order to quantitatively analyze HPV16 and HPV18 simultaneously,a novel "switch" sensor based on water-soluble two-color fluorescent CdTe QDs-ssDNA probe was constructed based on previous work.Green and red emitting CdTe QDs were created as fluorescent signals using the hydrothermal method.Porphyrin derivatives(NiTPP)were used to burst the fluorescence of CdTe QDs,and the synthesis conditions of NiTPP were optimized to increase the efficiency of quenching QDs.Dodecyldimethylbenzylammonium chloride(DDBAC)surfactant was used to change the charge on the NiTPP surface to facilitate electrostatic adsorption with ssDNA-modified QDs,and the burst efficiency was maximized due to FRET and photo-induced electron transfer(PET)effects.Meanwhile,the quantitative detection of HPV16 and HPV18 was theoretically supported by the particular recognition of DNA molecular hybridization,which enabled the release of ssDNA-QDs from the NiTPP surface and the recovery of various fluorescence intensities.The established assay provides a fresh concept for the simultaneous detection of different types of DNA.3.In order to further improve the sensitivity of the sensor,ssDNA was designed as hpDNA with hairpin structure,and combined with CQDs and gold nanoparticles(AuNPs)for detection of HPV DNA.At the same time,a DNA walker was constructed during the analysis of HPV16 and HPV18 to further accelerate the reaction rate.The probe device was created by grafting hpDNA(hairpin DNA)modified by CQDs and AuNPs together.Under the hairpin state,AuNPs would quench the fluorescence signature of CQDs nearby due to the FRET effect.The H-strand preferentially hybridized with the complementary hpDNA strand in the presence of the target analyte and moved automatically along the AuNPs.The opening hpDNA strand was stabilized by the subsequent replacement of hpDNA by HPV DNA,which caused a steady rise in the fluorescence signal of CQDs.The probe showed excellent sensitivity and specificity through fluorescence test and mechanism analysis,and the established detection method has certain potential in practical application.