Continuous monitoring of Naproxen by a cytochrome P450-based electrochemical sensor

• A sensor based on cytochrome P4501A2 for the monitoring of Naproxen in the pharmacological range is proposed.
• The proposed drug biosensor was fabricated by an easy and low-cost procedure.
• Calibration of NAP is performed in a complex sample such as mouse serum showing good sensitivity.
• A study of the stability of the sensor based on cytochrome P450 was made over a 36-h period.
• The sensor was employed to monitor drug delivery in real-time by using a micro-osmotic pump.

This paper reports the characterization of an electrochemical biosensor for the continuous monitoring of Naproxen based on cytochrome P450. The electrochemical biosensor is based on the drop-casting of multi-walled carbon-nanotubes (MWCNTs) and microsomal cytochrome P4501A2 (msCYP1A2) on a graphite screen-printed electrode (SPE).The proposed biosensor was employed to monitor Naproxen (NAP), a well-known anti-inflammatory compound, through cyclic voltammetry. The dynamic linear range for the amperometric detection of NAP had an upper limit of 300 µM with a corresponding limit of detection (LOD) of 16±1 µM (S/N=3), which is included in NAP physiological range (9–300 µM). The MWCNT/msCYP1A2-SPE sensor was also calibrated for NAP detection in mouse serum that was previously extracted from mice, showing a slightly higher LOD (33±18 µM).The stability of the msCYP1A2-based biosensor was assessed by longtime continuous cyclic voltammetric measurements. The ability of the sensor to monitor drug delivery was investigated by using a commercial micro-osmotic pump. Results show that the MWCNT/msCYP1A2-SPE sensor is capable of precisely monitoring the real-time delivery of NAP for 16 h. This work proves that the proposed electrochemical sensor might represent an innovative point-of-care solution for the personalization of drug therapies, as well as for pharmacokinetic studies in both animals and humans.