RESUMO
Objective To establish a simple and practical superparamagnetic immunochromatographic test strip for rapidly monitoring human serum level of CA72-4. Methods Water-soluble carboxylated super-paramagnetic nanoparticles were prepared with a modified one-step hydrothermal synthesis method. Magnetic probe was prepared by immobilizing specific antibody (mAb1) onto the surface of nanoparticles. Following with optimization and assembly of the test strip , we evaluated sensitivity , specificity , stability of this method for serum CA72-4 detection. Results The optimized test strip provided not only the qualitative results, but also the high sensitivity quantitative detection through stable magnetic signal. The detection limit was 0.83 IU/mL. One hundred clinical samples ( 70 positive and 30 negative ) were measured to assess these test strips with high sensitivity (99%) and high specificity (93%). The test strip and magnetic signal possessed high stability. Conclusion A rapid and quantitative detection of CA72-4 by the test strip was accomplished. This method is rapid, sensitive and quantitative, possessing great potential in large sample screening or in-home testing.
