Highly sensitive fluorescent detection of p53 protein based on DNA functionalized Fe₃O₄ nanoparticles

The accurate quantification of p53 protein expression level is of great importance for cancer diagnosis. Here, a highly sensitive fluorescent sensor based on DNA functionalized magnetic nanoparticles was developed for the detection of p53 protein expression. Instead of a monoclonal antibody, a consensus DNA was employed to capture p53 protein. Meanwhile the fluorescent dye tethered DNA was used as the signal output instead of enzyme tagged nanoparticle or antibody. Consequently, our developed method is cost-effective for both the p53 capture and detection by compared with the conventional immunoassay. The biosensor developed by the above strategy was used to quantitatively detect p53, which yields a detection limit of 8 p.M. with the linear range of 50 p.M. to 2 nM. The sensitive for specific p53 detection was achieved due to the facile magnetic separation from the complex condition, and the reduced non-specific absorption effect by dextran. Moreover, the method is able to measure p53 from real cell lysate without extensive sample pretreatment/separation. The developed p53 biosensor has high sensitivity, good selectivity and reliable accuracy. It demonstrates great potential in clinical cancer diagnosis and early detection of cancer.