Exosomal microRNAs array sensor with a bioconjugate composed of p53 protein and hydrazine for the specific lung cancer detection

Rabbee G. Mahmudunnabi, Muhammad Umer, Kyeong Deok Seo, Deog Su Park, Jae Heun Chung, Muhammad.J.A. Shiddiky, Yoon Bo Shim

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


For the early diagnosis of lung cancer, a novel strategy to detect microRNAs encapsulated in exosomes with immunomagnetic isolation was demonstrated for the selective extraction of exo-miRNAs from patient serum. Here, miRNA was captured from lysed exosomes in specially designed capture probe modified magnetic beads, followed by T4 DNA polymerase-mediated in situ formation of chimeric 5′-miRNA-DNA-3′ (Target). The poly-(2,2′:5′,2′′-terthiophene-3′-(p-benzoic acid)) (pTBA)-modified electrode harbors Probe-1 DNA that hybridizes to the 5′ end of the chimera, followed by hybridization of Probe-2 DNA to the 3′ end of the chimera, resulting in the formation of a 20-nucleotide-long dsDNA consensus sequence for p53 protein binding. A bioconjugate composed of p53 and hydrazine assembled on AuNPs (p53-AuNPs-Hyd) recruits the p53 protein to recognize a specific sequence, forming the final sensor probe (pTBA-Probe-1:Target/Probe-2:bioconjugate), where hydrazine functions as an electrocatalyst to generate amperometric signal from the reduction of H2O2. This sensor has double specificity via selective capture of the target in Probe-1 and p53 recognition, which shows excellent analytical performance, revealing a dynamic range between 100 aM and 10 pM with a detection limit of 92 (±0.1) aM. For practical applications, we prepared a multiplexed array sensor to simultaneously detect four exo-miRNAs (miRNA-21, miRNA-155, miRNA-205, and miRNA-let-7b) up to femtomolar levels from 1.0 mL to 125 μL of cell culture (A549, MCF-7 and BEAS-2B) media and lung cancer patient serum samples, respectively.

Original languageEnglish
Article number114149
Number of pages10
JournalBiosensors and Bioelectronics
Early online date09 Mar 2022
Publication statusPublished - 01 Jul 2022


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