Application Of Lateral Flow Strips In Detection Of Biomarkers Based On AuNPs-Aptamer Probes

Lateral flow platforms have become an excellent candidate for the identification of clinically relevant analytes because they are disposable,rapid,portable,user-friendly and cost-effective.In a typical lateral flow assay,reporter particles are transported by capillary action in a porous material and accumulate to form a visible or fluorescent line under the presence of analytes.Presently,there is a growing interest in the development of lateral flow detection of cancer biomarkers,metal ions,proteins,viruses,and nucleic acid.Nucleic acid detection is the gold standard for diagnosis of many infectious diseases.Most of nucleic acid assay strategies require tedious experimental procedures,costly and sophisticated equipments that may not be available in many laboratories.As a result,an affordable on-site technique for fast,sensitive,user-friendly biomarker detection with high efficiency has become indispensable and urgently needed.The highly sensitive detection of biomarkers is necessary in clinical diagnosis,genetics therapy,drug discovery,food safety and warning against biowarfare agents.In this work,we mainly focused on improving sensitivity and widening detetion range of lateral flow biosensors.The main contents of this paper include two aspects as follows:(1)A novel three-dimensional AuNPs-DNA network structure amplification strategy was employed to design a lateral flow biosensor by inducing streptavidin coated gold nanoparticles(Au-SA)in this paper.Sensitive detection of nucleic acid with point-of-care analysis is significant for infectious agent and early diagnosis and treatment of genetic diseases.The use of these particles in rapid ultrasensitive point of care(POC)lateral flow assays,which leads to limit of detection of 0.01 pM without PCR(polymerase chain reaction).The proposed method was 4 orders of magnitudes more sensitive than traditional sandwich assay labled with AuNPs.Furthermore,the assay owns good reproducibility and stability.This disposable,low-cost and user-friendly device will prove practical diagnostic applications.(2)The lateral flow assay strip sensor possesses many advantages as a diagnostic device,including the capabilities of rapid,one-step assay performance,and high throughput production.A major limitation of the sensor,however,is its difficulty in measuring a broad concentration range of target proteins,including thrombin(TB),due to the “hook effect”.In this study,we report the use of a three-line LFB strip sensor,adding an antigen line to the conventional two-line LFB,for detecting TB within a broad concentration range in human sera.We introduced an TB line between test and control lines in the LFB.The TB level in test samples was generated by data processing from the intensities of three lines.The strip sensor measured a linear detection range of TB concentration from 1 nM to 500 ?M within 10 min,with a calculated limit of detection of 0.54 nM.This novel and easy-to-use TB sensor can be a useful tool for rapid,sensitive,and cost-effective detection of a broad physiological concentration range of TB capabilities that are vital for various diagnostic applications.