title: Tuning the sol-gel microenvironment for acetylcholinesterase encapsulation.
abstract: The effect of the sol-gel microenvironment on the activity of acetylcholinesterase, an enzyme of high bio-analytical interest, is presented and is correlated to the overall analytical performance of corresponding biosensors. The sol-gel membranes are initially optimized with respect to the catalyst and the TEOS:H2O ratio (r), for mechanical stability, porosity, and hydrophobicity as well as in terms of enzymatic activity. FT-IR and electrochemical impedance spectroscopy (EIS) are used to probe the configuration and rotational mobility of the enzyme within the sol-gel matrices. Overall, it is observed that the rotational mobility of the protein can be correlated with the sensitivity of the biosensor. Optimum biosensor performance is obtained for base-catalyzed sol-gels with r values close to 2. The biosensor has sensitivity of 2.5 microA/mm, a linear range of response between 1 and 3mm, response time of about 30s, and sensor-to-sensor reproducibility (RSD) of 3%. These analytical characteristics are far superior to previously reported sol-gel biosensors.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Crete, Knossou Ave., Iraklion, 71409, Crete Greece. ss549@cornell.edu
authors.forename: Sofia
authors.initials: S
authors.lastname: Sotiropoulou
authors.forename: Nikos A
authors.initials: NA
authors.lastname: Chaniotakis
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry*; D001672:Biocompatible Materials; D015374:Biosensing Techniques; D002138:Calibration; D002384:Catalysis; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004563:Electrochemistry; D004566:Electrodes; D008855:Microscopy, Electron, Scanning; D044367:Phase Transition; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D014867:Water; D000110:Acetylcholinesterase