Wide-Linear Range Cholesterol Detection Using Fe <sub>2</sub> O <sub>3</sub> Nanoparticles Decorated ZnO Nanorods Based Electrolyte-Gated Transistor
Marya Khan, Vandana Nagal, Sakeena Masrat, Talia Tuba, Nirmalya Tripathy, Mohammad Khalid Parvez, Mohammed S. Al‐Dosari, Ajit Khosla, Hidemitsu Furukawa, Aurangzeb Khurram Hafiz, Rafiq Ahmad
Abstract
Electrolyte-gated transistor (EGT)-based biosensors are created with nanomaterials to harness the advantages of miniaturization and excellent sensing performance. A cholesterol EGT biosensor based on iron oxide (Fe 2 O 3 ) nanoparticles decorated ZnO nanorods is proposed here. ZnO nanorods are directly grown on the seeded channel using a hydrothermal method, keeping in mind the stability of nanorods on the channel during biosensor measurements in an electrolyte. Most importantly, ZnO nanorods can be effectively grown and modified with Fe 2 O 3 nanoparticles to enhance stability, surface roughness, and performance. The cholesterol oxidase (ChOx) enzyme is immobilized over Fe 2 O 3 nanoparticles decorated ZnO nanorods for cholesterol detection. With cholesterol addition in buffer solution, the electro-oxidation of cholesterol on enzyme immobilized surface led to increased the biosensor’s current response. The cholesterol EGT biosensor detected cholesterol in wide-linear range (i.e., 0.1 to 60.0 mM) with high sensitivity (37.34 μ A mM −1 cm −2 ) compared to conventional electrochemical sensors. Furthermore, we obtained excellent selectivity, fabrication reproducibility, long-term storage stability, and practical applicability in real serum samples. The demonstrated EGT biosensor can be extended with changing enzymes or nanomaterials or hybrid nanomaterials for specific analyte detection.