Rapid Detection Of BPA And E2 Based On Upconversion Fluorescence Biosensing Technology

Water is the source of life,and water safety is particularly important.Environmental estrogens?EEs?have gradually become an important cause of chemical pollution in water sources.Bisphenol A?BPA?and estradiol?E2?,as two typical EEs,are widely concerned due to their widespread and long time damage.So,it is imperative to establish a rapid,convenient and efficiency method to detect them.ObjectivesIn this study,two typical EEs BPA and E2 were selected as research objects.Based on up-converting phosphor technology,biosensor technology and fluorescence resonance energy transfer?FRET?,two sensing technology systems was developed for BPA and E2 detection with high efficiency?Methods1.Based on upconversion fluorescence probe and FRET for bisphenol A detection.The NaYF₄:Yb³⁺,Er³⁺UCNPs were prapareded by solvothermal method with slightly modified.The UCNPs were characterized by transmission electron microscopy?TEM?a6nd Fourier transform infrared spectroscopy?FTIR?.After surface modified,upconversion fluorescence probe could make FRET phenomenon enable under the existence of TAMRA-labled complementary sequence.With different concentration of bisphenol A in the system,the fluorescence intensity of UCNPs showed a significant linear change.2.Based on the AuNP-AuNP-UCNP triple structure for high efficient detection of bisphenol A and E2.The gold nanoparticles?AuNPs?and upconversion particles?NaYF₄:Yb,Er,Gd,UCNPs?,as two optical probes,were connected the aptamer of bisphenol A and estradiol,respectively.A complementary sequence was designed as a bridge to combine with two aptamers forming AuNP-AuNP-UCNP triple structure.Due to the specificity combine between aptamer and small molecule,the AuNPs or UCNPs would detach from the triple structure once bisphenol A and estradiol existence.The products were separated by centrifugation and measured the fluorescence intensity of UCNPs in supernatant and UV-vis absorbance intensity of AuNPs in precipitation to quantify BPA and E2.Results1.The results of trace bisphenol A detection based on the upconversion fluorescence probe and FRET:the average diameter of NaYF₄:Yb³⁺,Er³⁺UCNPs we choose in this study was about 73 nm,with a 6 nm silica layer coated on the surface.Under the optimal experimental conditions,the fluorescence intensity of UCNPs was linear with the logarithm of the BPA concentration in the range from 0.1 ng mL^-11 to25 ng mL^-11 with the detection limit of 0.05 ng mL^-1?R²=0.9938?.The recoveries were in general between 91.00%and 108.60%and the RSD was below 4.5%in actual water from Haihe,Tianjin.2.The results efficient detection of bisphenol A and estradiol based on the sensing system of AuNP-AuNP-UCNP triple structure:under the optimal conditions of the reaction temperature 30?,pH 7.8,this method exhibited good linear range for determination of bisphenol A and estradiol from 2 ng/mL to 200 ng/mL and from 10ng/mL to 150 ng/mL,with the limits of detection of 0.2 ng/mL and 0.5 ng/mL,respectively.What's more,this sensing system could apply to actual water detection,with the recoveries between 86.07%and 107.35%,and the relative standard deviation below 6.8%.The triple structure could be kept for 9 days at 4?,stability experiments showed good stable and reliable.ConclusionsTwo biosensing technology systems for the detection of BPA and E2 were successfully constructed with the advantages of high sensitivity,high specificity and time saving.This study may shed light on the rapid detection of environmental estrogens,possessing the theoretical value and application prospects.