title: Preparation, characterization and application of polyaniline nanospheres to biosensing.
abstract: Polyaniline nanospheres (PANI-NS) prepared by morphological transformation of micelle polymerized camphorsulfonic acid (CSA) doped polyaniline nanotubes (PANI-NT) in the presence of ethylene glycol (EG) have been characterized by X-ray diffraction, atomic force microscopy, transmission electron microscopy, scanning electron microscopy, Fourier transform infra-red and UV-Visible spectroscopy. A PANI-NS (60-80 nm) film deposited onto an indium-tin-oxide (ITO) coated glass plate by the solution casting method has been utilized for covalent immobilization of biomolecules (cholesterol oxidase (ChOx)) viaN-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry for fabrication of a cholesterol biosensor. The ChOx/PANI-NS/ITO bioelectrode detects cholesterol in the concentration range of 25 to 500 mg dL(-1) with sensitivity of 1.3 x 10(-3) mA mg(-1) dL and regression coefficient of 0.98. Further, this PANI-NS based bioelectrode shows fast response time (10 s), low Michaelis-Menten constant (2.5 mM) and shelf-life of 12 weeks. The spherical nanostructure observed in the final morphology of the PANI-NS film is attributed to hydrogen bonding interactions between PANI-NT and EG.
authors.affiliation: Department of Science and Technology Centre on Biomolecular Electronics, National Physical Laboratory, CSIR, Dr K. S. Krishnan Marg, New Delhi 110012, India.
authors.forename: Chetna
authors.initials: C
authors.lastname: Dhand
authors.forename: Maumita
authors.initials: M
authors.lastname: Das
authors.forename: Gajjala
authors.initials: G
authors.lastname: Sumana
authors.forename: Avanish Kumar
authors.initials: AK
authors.lastname: Srivastava
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Pandey
authors.forename: Cheol Gi
authors.initials: CG
authors.lastname: Kim
authors.forename: Monika
authors.initials: M
authors.lastname: Datta
authors.forename: Bansi Dhar
authors.initials: BD
authors.lastname: Malhotra
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002784:Cholesterol / Q000032:analysis; D002789:Cholesterol Oxidase / Q000737:chemistry / Q000378:metabolism; D055664:Electrochemical Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006860:Hydrogen Bonding; D054118:Nanospheres / Q000737:chemistry* / Q000648:ultrastructure; D017971:Tin Compounds
chemical_list: D000814:Aniline Compounds; D004800:Enzymes, Immobilized; D017971:Tin Compounds; C416807:polyaniline; C109984:indium tin oxide; D002784:Cholesterol; D002789:Cholesterol Oxidase