Covalent immobilization of cholesterol oxidase and poly(styrene-co-acrylic acid) magnetic microspheres on polyaniline films for amperometric cholesterol biosensing

• Published in: Analytical methods Vol. 5; no. 6; pp. 1392 - 1398
• Main Authors: Le Huy, Nguyen, My Thuy, Nguyen Thi, Binh, Nguyen Hai, Thinh, Nguyen Ngoc, Trang, Mai Thu, Chinh, Huynh Dang, Ngoc, Pham Thien, Phuc, Nguyen Xuan, Anh, Nguyen Van, Lam, Tran Dai
• Format: Journal Article
• Language: English
• Published: 01.01.2013
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/c2ay26179k

Magnetic Fe sub(3)O sub(4) nanoparticles (Fe sub(3)O sub(4) NPs) were synthesized by co-precipitation (of Fe super(2+) and Fe super(3+)) and surface-carboxylated by poly(styrene-co-acrylic acid) (PSA). Then they were thoroughly characterized by Scanning Electron Microscope and Transmission Electron Microscope analyses. Using glutaraldehyde cross-linking immobilization strategy, cholesterol oxidase (ChOx) was immobilized onto Fe sub(3)O sub(4)/PSA microspheres. The Fe sub(3)O sub(4)/PSA-ChO xhas been successfully synthesized on the planar platinum polyaniline (PANi) modified electrode. PANi/Fe sub(3)O sub(4)/PSA-ChOxsensing properties were studied using cyclic voltammetric and chronoamperometric techniques. Under the optimized experimental conditions the biosensor shows excellent features, such as wide linear range, 0.2 to 1.8 mM (R super(2) = 0.9901), low detection limit (0.02 mM), short response time (5-10 s), and high sensitivity (8796 mu A mM super(-1) cm super(-2)). The interference test with selected organic compounds, such as glucose, ascorbic acid, uric acid, and acetaminophen indicated high selectivity of the above sensor. It can be proven that the proposed PANi/Fe sub(3)O sub(4)/PSA-ChOxbased sensing concept could be successfully used for other biodetections.