Novel Competitive Chemiluminescence DNA Assay Based on Fe₃O₄@SiO₂@Au-Functionalized Magnetic Nanoparticles for...

A simple, rapid response time and ultrahigh sensitive chemiluminescence (CL) DNA assay based on Fe₃O₄@SiO₂@Au-functionalized magnetic nanoparticles (Au-MNPs) was developed for detection of p53 tumor suppressor gene. In this study, 2',6'-dimethylcarbonylphenyl-10-sulfopropyl acridinium-9-carboxylate 4'-NHS ester (NSP-DMAE-NHS), as a new kind of highly efficient luminescence reagent, was immobilized on the complementary sequence of the wild-type p53 (ssDNA) to improve the detection sensitivity. The optimal concentration of ssDNA-(NSP-DMAE-NHS) conjugates mixed with the wild-type p53 (wtp53) samples respectively. Then, the wtp53-Au-MNPs conjugates were added to continue the competitive reaction in the above solution. Subsequently, the Au-MNPs separated under magnetic field, measured by a homemade luminescent measurement system. Under optimal conditions, the method exhibited ultrasensitive sensitivity with a detection limit of 0.001 ng mL^-1 (0.16 pM), a wide range of liner response from 0.001 ng mL^-1~6.6 μg mL^-1. Therefore, the immunomagnetic nanocomposites-based detection strategy was rapid, low-cost, and highly sensitive that can be easily extended to the early diagnosis of cancer development and monitoring of patient therapy.