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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films

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Rodrigues, Raul T. [1] ; Morais, Paulo V. [2, 3] ; Nordi, Cristina S. F. [1] ; Schoening, Michael J. [4, 5] ; Siqueira, Jr., Jose R. [2] ; Caseli, Luciano [1]
Total Authors: 6
[1] Fed Univ Sao Paulo UNIFESP, Inst Environm Chem & Pharmaceut Sci, BR-09913030 Diadema, SP - Brazil
[2] Fed Univ Triangulo Mineiro UFTM, Inst Exact Sci Nat & Educ, BR-38064200 Uberaba, MG - Brazil
[3] Sao Paulo State Univ, Inst Chem, Interdisciplinary Lab Electrochem & Ceram, BR-14800900 Araraquara, SP - Brazil
[4] FH Aachen, INB, Campus Julich, D-52428 Julich - Germany
[5] Forschungszentrum Julich, Inst Complex Syst ICS 8, D-52425 Julich - Germany
Total Affiliations: 5
Document type: Journal article
Source: Langmuir; v. 34, n. 9, p. 3082-3093, MAR 6 2018.
Web of Science Citations: 7

Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air-water interface were investigated by surface pressure-area isotherms, surface potential-area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte insulator-semiconductor (EIS) devices, through the Langmuir-Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV-vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance-voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications. (AU)

FAPESP's process: 15/23446-0 - Smart surfaces: nanostructured and bioinspired systems for the investigation of molecular interactions in membrane models and for the production of devices for biosensors and environmental analysis
Grantee:Luciano Caseli
Support Opportunities: Regular Research Grants
FAPESP's process: 16/01867-6 - Hybrid Langmuir-Blodgett film of carbon nanotubes and algal polysaccharides to immobilize enzymes
Grantee:Raul Torres Rodrigues
Support Opportunities: Scholarships in Brazil - Scientific Initiation