A new aptamer/polyadenylated DNA interdigitated gold electrode piezoelectric sensor for rapid detection of Pseudomonas aeruginosa

Rapid detection of Pseudomonas aeruginosa (P. aeruginosa) is of great importance for accurate diagnosis and treatment of infected patients. In this study, a novel method was developed for the selective detection of P. aeruginosa by combing the sandwich type complex of magnetic bead/aptamer/polyadenylated-DNA with the sensitive detection platform of gold (Au) interdigital electrode connected to a multichannel series piezoelectric quartz crystal (Au IDE-MSPQC) system. Here, the magnetic bead (MB) was used as carrier for immobilization of the aptamer of P. aeruginosa. Polyadenylated DNA was bound to the aptamer through complementary strand pairing. When the P. aeruginosa was present in the sample solution, the polyadenylated DNA was replaced by the P. aeruginosa because of the specific interaction between P. aeruginosa and its aptamer. The released polyadenylated DNA strand in the detected solution could adsorb onto the surface of Au IDE by virtue of the strong interaction between adenine (A) and Au IDE, and result in sensitive frequency shift response of the MSPQC sensor. The limits of detection (LOD) of the method were as low as 9 CFU/mL in buffer and 52 CFU/mL in simulated blood sample. The proposed method was successfully applied to the selective detection of P. aeruginosa in blood samples. The constructed sensor is expected to find application for the rapid detection of P. aeruginosa in environment, food and clinical diagnosis.