Immunochromatography Assay Based On Magneticgold Nanoparticles For Detection Of CA15-3

Breast cancer(BC)is by far the most usual life-threatening malignancy in women worldwide.Carbohydrate antigen 15-3(CA15-3),as one of the most important tumor markers for early diagnosis and evaluation of curative effect of BC.At present,the detection methods we used widely have many disadvantages,which inhibit their further application.Therefore,develop a method for detecting CA15-3 with advantages of fast,simple,cheap as well as a lower detection limit has essential value to economy and society.In this article,the method integrated magnetic microspheres and conventional colloid gold immunochromatography(GICA)for detcting CA15-3 was developed for the first time.The synthesis of Chitosan/Fe3O4 magnetic nanoparticles was carried by adorpting the method of inverse suspension polymerization.After process optimization,the average diameter of nanoparticles we obtained was 633.9 nm and polydispersivity Index(PDI)which represented dispersivity was 0.264.Otherwise,nanogold colloid(5-20 nm)was prepared with method of a reduction of chloroauric acid by sodium citrate,and the magnetic nanoparticles coupled with gold nanoparticles directly.The average size of magnetic nanogold particles was 896 nm and PDI was 0.709.Besides,the saturation magnetization was close to 1/2 of magnetic nanoparticles.And through elemental analysis,the content of Auo was 40.73%,which also suggested that the Au nanoparticles won't change the saturation magnetization that much.The GICA kit based on magnetic microspheres including strip and working solution.For marking CA15-3 monoclonal antibody,the result showed that the optimal pH and the minmun amount were pH=9.0 and 1.0 mg/ml respectively.Furthermore,pH=9.0 Boric acid and borax buffer solution and 8.0%Tween-80 were the optimum conditions for the working solution.Finally,compared with the cutoff value of 63 U/ml of the traditional GICA,a 2 times higher sensitivity was obtained with the cutoff value of 31.5 U/mL,and the operational processes was generally finished within 30 min.In addition,no cross-reactivity to other tumor markers of BC was found.In conclusion,the result was conformed with our expection,and we also hope that the detection kit based on magnetic nanoparticles will be used widely in furture.