A Study Of Carbohydrate Antigen 153 Based On Upconversion Fluorescence Resonance Energy Transfer Analysis Methods

Breast cancer is a common malignancy with increasing incidence in the world that endangers women′s health.Early diagnosis is an important way to improve the cure rate of breast cancer.CA153 is an important biomarker of breast cancer.30%-50%of patients with primary breast cancer have significantly higher levels of CA153in serum.Accurate diagnosis of CA153 can provide a reliable reference for the early diagnosis of breast cancer.Fluorescence resonance energy transfer（FRET）is a homogeneous detection technique with good selectivity,sensitive and simplicity,which has received widespread attention in the biomedical field.However,majority of rencent LRET-based probes use visible light as the excitation source,resulting in strong autofluorescence,which brings significant interference to the detection results.Upconversion nanoparticles（UCNPs）doped with rare earth ions have the advantages of near-infrared excitation and anti-Stokes emission,which can effectively avoid the interference of biological autofluorescence and improve the detection sensitivity.Therefore,UCNPs-based CA153 probes were constructed.These probes can be successfully applied in CA153 detection of in serum.The details are as follows:1、FRET-based CA153 probe was constructed with FAM as energy receptor.The oleic acid-coated UCNPs was firstly synthesized by solvothermal method and oleic acid was removed by acid treatment.PAA-UCNPs with carboxyl groups were obtained by polyacrylic acid（PAA）treatment.PAA-UCNPs and FAM were modified into different ends of the hairpin DNA by amidation reaction,which shortened the distance between the energy donor and the energy acceptor and triggered the FRET and quench the upconversion fluorescence of UCNPs.In presence of CA153,its specific recognition with the aptamer sequence in the hairpin structure opened the loop structure of the molecular beacon,resulting in the separation of energy donor and acceptor and the inhibition of FRET.The quantitative detection of CA153 can be achieved according to the degree of fluorescence recovery.The linear range in buffer is 0.01-150 U/m L.The probe has good stability and selectivity and can effectively resist the interference of common biological molecules,such as glucose,glycine and human serum albumin.2、A CA153 fluorescent probe excited by near-infrared light was constructed in the previous work,but its emission is still located in the visible region.For this reason,the second work in this paper constructed a near-infrared excitive and near-infrared emissive CA153 probe,which used the emission around 809 nm of Tm³⁺-doped UCNPs as detection signal and polydopamine nanoparticles（PDA NPs）as the energy donor.The assembly of PDA NPs with UCNPs was achievedπ-πstacking between the PDA NPs and the aptamer.The fluorescence around 809 nm of UCNPs is effectively quenched and the emission of PDA NPs around 850 nm was emhanced.In the presence of CA153,its specific binding with aptamer separate UCNPs from PDA NPs,which inhibited FRET and restored the fluorescence around 809 nm of UCNPs.The probe is not only suitable for the detection of CA153 in buffer,but also can be successfully applied in quantitative analysis of CA153 in human serum,which is potential to be a powerful tool for the early diagnosis of breast cancer.