3D MoS2-AuNPs carbon paper probe for ultrasensitive detection and discrimination of p53 gene.

• The MoS 2 -AuNPs probe showed uniquely inherited structure and excellent electrochemical characteristic. • The carbon paper functionalized with MoS 2 -AuNPs demonstrated the outstanding detection performance of p53 gene. • The biosensor exhibits a relatively lower detection limit of 68 fM for p53 gene detection. • The planned biosensor could discriminate well between the mutated and wild type p53 gene extracted from tumor cells. p53 gene is one of the most important anticancer genes and has been recognized as a typical biomarker for the early diagnosis, classification, and prognosis evaluation of cancers. In this work, a novel biosensing strategy integrating MoS 2 -AuNPs modified carbon paper (CP) conductive substrate and enzyme signal amplification technique was developed for p53 gene detection. We constructed an immobilized DNA S1 probe and a biotinylated DNA S3 probe, which could induce the formation of an S1-p53-S3 DNA sandwich complex in the presence of target sequence p53. After conjugating avidin-HRP via biotin-avidin reaction, 3,3',5,5'-tetramethylbenzidine would be catalyzed for signal amplification in the presence of H 2 O 2 so that the induced electrochemical response would change with proportional to the abundance of p53 gene. The proposed biosensor exhibited two linearities in the range of 1.0 × 10−15 ∼ 1.0 × 10-12 M and 1.0 × 10-12 ∼ 1.0 × 10-6 M, and the limit of detection (LOD) was 68 fM. No significant interferences were observed during detecting real serum samples. Moreover, it is worth pointing out that the biosensor together with its disposable, low-cost, and stable features can discriminate well between the mutated and wild type p53 gene extracted from tumor cells (wtTP53 in MCF-7 and mutated in SK-BR-3), demonstrating a promising applicability for clinical test. [ABSTRACT FROM AUTHOR]