The Development of an Amperometric Enzyme Biosensor Based on a Polyaniline-Multiwalled Carbon Nanocomposite for the Detection of a Chemotherapeutic Agent in Serum Samples from Patients

Polyaniline was electrochemically polymerized onto the platinum electrode modified with a mixture of Nafion and multiwalled carbon nanotube (PANI/MWCNT/Nf/Pt) to detect ammonium ion. The nanobiosensor (ASNase/PANI/MWCNT/Nf/Pt) was then prepared by immobilizing L-asparaginase (L-ASNase) on the PANI/MWCNT/Nf nanocomposite. The prepared nanobiosensor was used for the rapid and sensitive detection of serum concentration of the anticancer agent L-asparagine (L-Asp) during chemotherapy. The nanobiosensor has dynamic ranges of zero to 180 μM. The sensitivity of the nanobiosensor was 0.829 μA μM−1 cm−2, and the response time was less than 30 s. The detection limit was 140 nM of L-Asp. The Michaelis–Menten constant ( K m ) was measured to be 36.2 mM. The nanobiosensor was successfully applied for the determination of L-Asp in the blood samples of leukemia patients.