A self-assembled electrochemical aptasensor for one-step rapid detection of cisplatin in blood via aptamer conformational change

Cisplatin (DDP), as a broad-spectrum anticancer drug, requires dynamic monitoring of its blood concentration and intervention in its dosage administration to balance efficacy and safety due to significant individual differences in its metabolism, side effects, and resistance in different patients. However, rapid and robust methods for monitoring and quantifying DDP in complex biological fluids are still lacking. This work presents an electrochemical aptamer-based ( E -AB) sensor for rapid measurement of DDP concentration in blood. In which capture probe aptamers were designed constructed by visualizing and analyzing their binding pockets, followed by molecular docking and circular dichroism to screen the aptamer Apt25, which has a small binding energy and a large conformational change, for use in the construction of the sensor. In the presence of DDP, the aptamer undergoes a conformational change at the electrode interface, altering the electron transfer rate of the electroactive label to detect DDP concentration variations. After systematically using electrochemical techniques to optimize the sensor testing conditions, the sensor can directly analyze and detect DDP in urine and blood with a measurement range of 0.001–2 mM and a detection limit of 1 μM, which satisfies the needs of clinical testing. The spiked recoveries in different biological samples were 80.8–110% and 79–115.2%, respectively. In addition, the sensor has sufficient selectivity and stability, which is expected to enable real-time monitoring of DDP concentration for dosage adjustment and improvement of drug bioavailability at the clinical site.