Design And Application Of Nanomaterial-based Lateral Flow Strip Biosensor

The chromatography immunoassays also called the lateral flow strip biosensors(LFSB),have improves the situation of the traditional detection technology,including the procedure complexity,high-cost,time-consuming and so on.It provides a good selection and analysis platform for the fast,accurate and point-of-care detection of the target,and is widely used in clinical application and biomedical diagnosis.However,there are still space and aspects for improvement and optimization of LFSB,for example,the lack of the certain cancer markers,the sensitivity improvement,and the further simplification of detection procedure.In the present dissertation,we focused on developing advanced LFSBs for the resolution of these problems.Following is the brief introduction.1.A three-line lateral flow biosensor for logic detection of microRNAA rapid,sensitive,and accurate detection strategy for microRNA 16(miR-16)was developed,which combined the convenience of LFSB,the design flexibility of Y-shaped junction DNA probe,and the enhancement ability of endonuclease-assisted target recycling amplification.Under optimal conditions,the visual detection limit of miR-16 in aqueous solutions was 0.1 pM,which is 100-1000 times lower than that of visual or colorimetric methods in the literature.It can be used for on field and point-of-care testing and meet the urgent demand of sensitive and selective miRNA detection in remote rural areas without costly equipment.2.Different nanoparticle based LFSB for detection of IgG proteinsIn this study,we optimized the antibody labeling for IgG detection by LFSB.For this purpose,we labeled the detection antibody(anti-IgG)with three different colored particles:gold nanoparticles,magnetic nanoparticles or carbon nanotubes.The color produced on the test zone were red,brown and black,respectively.For ail three particles,the intensity of the test zone increased with the increase of the concentration in sample solution.The CNTs based-LFSB has the lowest detection limit,which is about two times lower than GNPs based-LFSB and five times lower than MNPs based-LFSB.The CNTs based-LFSB can have potentiality in detection of other cancer related biomarkers.3.Magnetized Carbon Nanotubes for Visual Detection of Proteins Directly in Whole Blood.The authors describe a magnetized carbon nanotube(MCNT)-based LFSB for visual detection of proteins directly in whole blood avoiding complex purification and sample pre-treatments.MCNT was synthesized by coating Fe3O4 nanoparticle on the shortened multiwalled carbon nanotube(CNT)surface via co-precipitation of ferric and ferrous ions within a dispersion of shorten multi walled CNT.The antibody-modified MCNT was used to capture target protein in whole blood;the formed MCNT-antibody-target protein complex was applied to the LFSB.The detection limit of the assay in whole blood was determined to be 10 ng mL-1(S/N=3)with a linear dynamic range of 10 to 200 ng mL-1.This study provides a rapid and low-cost approach for detecting proteins in blood,showing great promise for clinical application and biomedical diagnosis,particularly in limited resource settings.4.Lateral flow assay for carbohydrate antigen 19-9 in whole blood by using magnetized carbon nanotubesThe authors describe a rapid,low-cost and sensitive approach for the determination of carbohydrate antigen 19-9(CA 19-9)in whole blood by using MCNT and LFSB.Antibody against CA 19-9(Abi)was covalently immobilized on the MCNTs and were used to capture CA 19-9 in blood.After magnetic separation,the formed MCNT-Ab1-CA 19-9 complex was applied to the LFSB.Under optimized conditions,the assay has a detection limit as low as 30 U · mL-1 of CA 19-9 in blood.This is below the cutoff value(37 U mL-1)of CA 19-9.The assay duration for blood samples is 35 min.In our perception,the assay represents a rapid and low-cost tool for rapid determination of CA19-9 in blood that holds promise for clinical applications,particularly in limited resource settings.5.Lateral flow strip biosensor for complementary factor B 19-9 in whole bloodWe have developed a highly sensitive lateral-flow strip biosensor(LFSB)for CFB using MCNT as labels.Based on detection performance with CFB increase,monoclonal antibody was used as the detection antibody.The LFSB has a linear range of 5-100 ng mL-1 with a visual detection limit of 5 ng mL-1 CFB in buffer and CFB concentration in blood ranging from 46.88-750?g mL-1 can be detected in 25 min.The results has a high correlation with commercial ELISA kit.Our MCNT-based LFSB shows great promise in rapid,point of care detection and home self-testing of CFB.