title: Amperometric determination of serum total cholesterol with nanoparticles of cholesterol esterase and cholesterol oxidase.
abstract: We describe the preparation of glutaraldehyde cross-linked and functionalized cholesterol esterase nanoparticles (ChENPs) and cholesterol oxidase nanoparticles (ChOxNPs) aggregates and their co-immobilization onto Au electrode for improved amperometric determination of serum total cholesterol. Transmission electron microscope (TEM) images of ChENPs and ChOxNPs showed their spherical shape and average size of 35.40 and 56.97 nm, respectively. Scanning electron microscope (SEM) studies of Au electrode confirmed the co-immobilization of enzyme nanoparticles (ENPs). The biosensor exhibited optimal response at pH 5.5 and 40°C within 5 s when polarized at +0.25 V versus Ag/AgCl. The working/linear range of the biosensor was 10-700 mg/dl for cholesterol. The sensor showed high sensitivity and measured total cholesterol as low as 0.1 mg/dl. The biosensor was evaluated and employed for total cholesterol determination in sera of apparently healthy and diseased persons. The analytical recovery of added cholesterol was 90%, whereas the within-batch and between-batch coefficients of variation (CVs) were less than 2% and less than 3%. There was a good correlation (r = 0.99) between serum cholesterol values as measured by the standard enzymic colorimetric method and the current method. The initial activity of ENPs/working electrode was reduced by 50% during its regular use (200 times) over a period of 60 days when stored dry at 4°C.
authors: Department of Biochemistry, Maharshi Dayanand (M.D.) University, Rohtak, Haryana, 124001, India.
authors: V
authors: V
authors: Aggarwal
authors: Centre for Biotechnology, Maharshi Dayanand (M.D.) University, Rohtak, Haryana, 124001, India.
authors: J
authors: J
authors: Malik
authors: Centre for Biotechnology, Maharshi Dayanand (M.D.) University, Rohtak, Haryana, 124001, India.
authors: A
authors: A
authors: Prashant
authors: Centre for Biotechnology, Maharshi Dayanand (M.D.) University, Rohtak, Haryana, 124001, India.
authors: P K
authors: PK
authors: Jaiwal
authors: Department of Biochemistry, Maharshi Dayanand (M.D.) University, Rohtak, Haryana, 124001, India. Electronic address: pundircs@rediffmail.com.
authors: C S
authors: CS
authors: Pundir
mesh_terms: D015374:Biosensing Techniques; D002784:Cholesterol / Q000097:blood*; D002789:Cholesterol Oxidase / Q000378:metabolism*; D055664:Electrochemical Techniques / Q000379:methods*; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D002787:Sterol Esterase / Q000378:metabolism*
chemical_list: D002784:Cholesterol; D002789:Cholesterol Oxidase; D002787:Sterol Esterase
keywords: Bionanosensor; Cholesterol esterase nanoparticles; Cholesterol oxidase nanoparticles; Co-immobilization; Serum; Total cholesterol