An ALP enzyme-based electrochemical biosensor coated with signal-amplifying BaTiO 3 nanoparticles for the detection of an antiviral drug in human blood serum.

Tenofovir (TFV) is an antiviral drug used to treat the co-infections of HIV/HBV viruses. Accurate monitoring of TFV drug levels is essential for evaluating patient adherence, optimizing dosage, and assessing treatment efficacy. Herein, we propose an innovative electrochemical sensing approach by using the alkaline phosphatase (ALP) enzyme with the support of BaTiO 3 nanoparticles. An attractive sensitivity and selectivity of the developed sensor towards TFV detection were achieved. First, the nanoparticles were synthesized by following a single-step sol-gel method and characterized through various analytical techniques, including SEM, EDX, FT-IR, BET, zeta potential, XRD, and UV-vis and Raman spectroscopy. The suggested mechanism demonstrated the formation of a strong bond between TFV and the ALP enzyme, primarily through the phosphate group, resulting in enzyme inhibition. Various parameters like nanoparticle amount, electrode modification time with enzyme and BaTiO 3 nanoparticles, and drug incubation time were optimized. The biosensor demonstrated an outstanding limit of detection (LOD) of 0.09 nM and recovery percentages of 98.6-106% in human blood serum, indicating adequate repeatability and selectivity. The proposed biosensor can be converted into a portable device for measuring small sample volumes and observing patients for immediate medical care or personalized therapies. It achieved better sensitivity compared to existing methods, making it suitable for precise drug detection in microdoses.