Detection of Gentamicin for Patients with Peritonitis by a Packaged Piezoresistive Microcantilever Biosensor

Adverse drug reaction has received increasing attention recently. For some specific drugs with narrow therapeutic ranges, use of therapeutic drug monitoring (TDM) may reduce the adverse drug reactions for an individual to avoid drug toxicity. Gentamicin, managed in TDM, is a widely used antibiotic drug for patients with renal failure. This drug, composed of a mixture of related gentamicin components and fractions, is used to treat many types of bacterial infections, particularly those caused by Gram-negative organisms. In this study, a label-free drug detection of antibiotic gentamicin is made with the CMOS BioMEMS cantilever sensing transduction in a microfluidic channel. The sensor manufacturing technology utilizes 0.35 um 2P4M CMOS process with post MEMS processes of gold metallization and silicon dry etching. Meanwhile, this biosensing mechanism is based on protein-drug recognition, which results in conformational change and thus induced cantilever deflection. In this subproject, to enhance the sensor sensitivity, the CMOS BioMEMS cantilever sensor is firstly developed for the high capture antibody surface density of immobilization with the introduction of device electric field and simultaneous antibody-immobilized monitoring. The enhanced antibody immobilization is expected to significantly increase antibody-drug binding onto the sensing surface, and the simultaneous monitoring assures the device for biosensing detection and biosensor availability. By comparing the change of the signals in no electric field of antibody immobilization, the results showed that the signal of Gentamicin with 60 volt electric field was improved by around 2 folds. At last, the detection of the Gentamicin with concentration of 50 µg/ml、35 µg/ml and 20 µg/ml was achieved by a packaged piezoresistive microcantilever biosensor with the 60 volts of applied electric fields enhancement. The induced change in resistance was measured 16.77 ppm, 9.91 ppm and 4.09 ppm respectively. The results presented an excellent agreement with those in conventional method PETINIA. Detection of gentamicin by the CMOS-MEMS cantilever biosensor provides a promising potential for a portable, palm-sized device in service of patient-centered health care.