title: Invertase-nanogold clusters decorated plant membranes for fluorescence-based sucrose sensor.
abstract: In the present study, invertase-mediated nanogold clusters were synthesized on onion membranes, and their application for sucrose biosensor fabrication was investigated. Transmission electron microscopy revealed free nanoparticles of various sizes (diameter ~5 to 50 nm) along with clusters of nanogold (~95 to 200 nm) on the surface of inner epidermal membranes of onions (Allium cepa L.). Most of the polydispersed nanoparticles were spherical, although some were square shaped, triangular, hexagonal or rod-shaped. Ultraviolet-visible spectrophotometric observations showed the characteristic peak for nanoparticles decorated invertase-onion membrane at approximately 301 nm. When excited at 320 nm in the presence of sucrose, the membranes exhibited a photoemission peak at 348 nm. The fluorescence lifetime of this nanogold modified onion membrane was 6.20 ns, compared to 2.47 ns for invertase-onion membrane without nanogold. Therefore, a sucrose detection scheme comprised of an invertase/nanogold decorated onion membrane was successfully developed. This fluorescent nanogold-embedded onion membrane drop-test sensor exhibited wide acidic to neutral working pH range (4.0-7.0) with a response time 30 seconds (<1 min). The fabricated quenching-based probe had a low detection limit (2x10(-9) M) with a linear dynamic range of 2.25x10(-9) to 4.25x10(-8) M for sensing sucrose. A microplate designed with an enzyme-nanomaterial-based sensor platform exhibited a high compliance, with acceptable percentage error for the detection of sucrose in green tea samples in comparison to a traditional method. With some further, modifications, this fabricated enzyme-nanogold onion membrane sensor probe could be used to estimate glucose concentrations for a variety of analytical samples. Graphical abstract Synthesis and characterization of invertase assisted nanogold clusters on onion membranes and their application for fluorescence-based sucrose sensor.
authors.affiliation: Institute of Food Science and Technology, National Taiwan University, No.1, Roosevelt Road, section 4, Taipei, Taiwan. dipalibagal@yahoo.com.
authors.forename: Dipali
authors.initials: D
authors.lastname: Bagal-Kestwal
authors.affiliation: Institute of Food Science and Technology, National Taiwan University, No.1, Roosevelt Road, section 4, Taipei, Taiwan. rakeshkestwal@yahoo.co.in.
authors.forename: Rakesh Mohan
authors.initials: RM
authors.lastname: Kestwal
authors.affiliation: Institute of Food Science and Technology, National Taiwan University, No.1, Roosevelt Road, section 4, Taipei, Taiwan. bhchiang@ntu.edu.tw.
authors.forename: Been-Huang
authors.initials: BH
authors.lastname: Chiang
mesh_terms: D000490:Allium / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002462:Cell Membrane; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D049329:Nanostructures / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013395:Sucrose / Q000032:analysis*; D013662:Tea / Q000737:chemistry; D043324:beta-Fructofuranosidase / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D013662:Tea; D013395:Sucrose; D043324:beta-Fructofuranosidase