Immobilization of cholesterol oxidase and potassium ferricyanide on dodecylbenzene sulfonate ion‐doped polypyrrole film

Abstract

:Dodecylbenzene sulfonate (DBS)-doped polypyrrole (PPY) conducting polymer films were electrochemically deposited onto the indium-tin-oxide (ITO)-coated glass plates in aqueous medium. The enzyme cholesterol oxidase (ChOx) was immobilized on these DBS-PPY films by a physical adsorption technique. These ChOx-immobilized DBS-PPY films were characterized by ultraviolet-visible and Fourier transform infrared spectroscopy. The enzyme activity studies indicate that ϳ40% of ChOx leaches out from the ChOx/DBS-PPY film. The ChOx activity in the ChOx/DBS-PPY film was assayed as a function of cholesterol concentration. The results of amperometric measurements conducted on ChOx/DBS-PPY/ITO film show linearity over the range 2-8 mM of cholesterol solution. The ChOx/DBS-PPY/ITO electrodes exhibit a response time of 30 s and are stable for ϳ3 months at 4°C.

Recent advances in cholesterol biosensor

“…Many researchers have used conducting polymers to provide stability to a biosensor and to provide selectivity toward interferents. Among the conducting polymers, polypyrrole has been most widely studied polymer Singh et al, 2004a,b;Kumar et al, 2001;Brahim et al, 2001). Polyaniline (PANI), Singh et al, 2006a,b;Solanki et al, 2007b,c), diaminonaphthalene (Ruiz et al, 2004) and poly(vinylferrocenium) (Ozer et al, 2007) are some of the other polymers used for cholesterol biosensor fabrication.…”

“…In electrochemical detection cyclic voltammetric (CV) and amperometric technique are most widely employed. Cyclic voltammetric technique has been effectively utilized for the estimation of cholesterol in the system (Ropers et al, 2001;Kumar et al, 2001;Chou and Liu, 2005;Singh et al, 2006a;Zhou et al, 2006;Solanki et al, 2007b). Based on HRP-hydroxymethyl ferrocene (HMF)-carbon paste electrode and ChOx with ChEt in solution, Charpentier et al have estimated cholesterol concentration via chronoamperometric technique.…”

Nonenzymatic free-cholesterol detection via a modified highly sensitive macroporous gold electrode with platinum nanoparticles

“…So, surfactant Triton X-100 and 2-propanol were used to enhance the solubility of the cholesterol in the preparation of a cholesterol containing solution. After homogenization, the volume was made up to 100 ml with a 0.1 M phosphate buffered saline (PBS, pH 7.0) and thermostated at 35 • C (Kumar et al, 2001). The 0.1 M ascorbic acid (AA, 98%, Sigma), acetaminophen (AP, 99%, Sigma), and uric acid (UA, 99%, Sigma) were prepared by diluting them in a phosphate buffered saline (PBS, 0.1 M, pH 7.4) solution, respectively.…”

Polyaniline Langmuir–Blodgett film based aptasensor for ochratoxin A detection

“…Thin films prepared by different techniques of a variety of materials such as conducting polymers Prabhakar et al, 2008;Arora et al, 2007;Kumar et al, 2001;Gerard et al, 1999), gold nanoparticles , carbon nanotubes (Singh et al, 2010), metal oxides like Fe 2 O 3 (Prabhakar et al, 2010), ZnO (Ansari et al, 2009) have been used as matrices for immobilization of biomolecules. However, to obtain improved biosensing devices, design and analysis at the molecular level and oriented organization of biomolecules on the sensor surface are extremely important.…”