An electrochemical DNA biosensor coupled with dual amplification strategy based on DNA-Au bio-bar codes and silver enhancement for highly sensitive and selective detection of MDR1 gene

Given the tumors might develop multidrug resistance (MDR) during chemotherapy that leading to treatment failure, rapid and sensitive determination of MDR1 gene is an effective tool to monitor the development of MDR. Herein, we established an electrochemical deoxyribonucleic acid (DNA) biosensor coupled with dual amplification strategy based on DNA-Au bio-bar codes and enhancement of silver for sensitive and selective determination of MDR1 gene. Specifically, DNA-Au bio-bar codes as signal probe were prepared by immobilizing complementary and non-complementary sequences on gold nanoparticles (AuNPs), so as to reduce the cross reaction between the target and reporter DNA. In addition, AuNPs-catalyzed reduction of silver ions greatly amplified the current signal. Under the optimal conditions, the current signal was proportional to the base-10 logarithm of target DNA concentration in a wide range from 100 fM to 1 nM with a detection limit as low as 33 fM (S/N = 3). Moreover, without the need for target amplification, the prepared biosensor exhibited superior selectivity and high sensitivity even in the presence of other sequences. Therefore, the developed electrochemical DNA biosensor is a facile and sensitive platform for MDR1 gene detection.