Gentamicin drug monitoring for peritonitis patients by using a CMOS-BioMEMS-based microcantilever sensor.

We developed a Complementary Metal-Oxide-Semiconductor Bio-Microelectromechanical Systems (CMOS-BioMEMS) based piezoresistive microcantilever sensor for detecting gentamicin, a peritonitis therapeutic small-molecule drug. In recent years, the patient-centric concept has been emphasized. In such a trend, therapeutic drug monitoring (TDM) is especially crucial for patients with peritonitis to avoid adverse reactions from a high concentration of gentamicin in the blood. With the aid of a commercialized semiconductor manufacturing process, the microcantilever sensing platform can serve as a portable, low-cost device and offer real-time detection. With chemical surface modification and capture antibody immobilization, the sensor can detect the small-molecule (< 2 kDa) gentamicin directly. We also modified the pH value of the buffer solution and applied an external electric field to promote sensor sensitivity. Comparing the change of the signals in a non-electric field of antibody immobilization and a 60-volt electric field of antibody immobilization showed that the average signal response increased 1.8 times. In the detection of gentamicin with different concentrations of 10-200 μg/mL, the limit of detection (LOD) of the sensor was 9.44 µg/mL. Finally, the detecting result of a microrcantilever sensor was compared with the one measured by a common instrument in hospital, and the high correlation was expressed between them in gentamicin detection. The CMOS-BioMEMS-based piezoresistive microcantilever sensor has been demonstrated to have great potential as a point-of-care (POC) device for real-time drug concentration monitoring.