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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.)

Insertion of carbon nanotubes in Langmuir-Blodgett films of stearic acid and asparaginase enhancing the catalytic performance

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Author(s):
Rodrigues Rola Possarle, Luiz Henrique [1] ; Siqueira Junior, Jose Roberto [2] ; Caseli, Luciano [1]
Total Authors: 3
Affiliation:
[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
Total Affiliations: 2
Document type: Journal article
Source: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 192, AUG 2020.
Web of Science Citations: 0
Abstract

In this paper, carbon nanotubes (CNT) were adsorbed on stearic acid (SA) Langmuir monolayers to serve as matrices for the incorporation of asparaginase. The interaction between the components at the air-water interface was evaluated by surface pressure-area isotherms, surface potential-area isotherms, polarization-modulation reflection absorption infrared spectroscopy (PM-IRRAS), and Brewster angle microscopy (BAM). The enzyme expanded the monolayers and changed the thermodynamic and electrical properties of the SA-CNT monolayers, as detected with the isotherms. PM-IRRAS spectra showed that the enzyme keeps its secondary structure when adsorbed at the monolayers and also alters the morphology of the air-water interface, as identified with BAM. The hybrid floating films were transferred to solid supports through the Langmuir-Blodgett (LB) technique, and the cotransfer of the enzyme was confirmed with fluorescence spectroscopy. The catalytic activity of asparaginase in the LB films was studied with UV-vis spectroscopy, which showed that the presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity, but also helped conserve its enzyme activity after weeks, showing higher persisting values of activity. UV-vis spectroscopy also showed that the catalytic activity is dependent basically on the enzyme molecules present on the surface of the LB films since multilayer films did not provide a proportional increase of enzyme activity. These results are related to the synergism between the compounds on the active layer, leading to a molecular architecture that allowed the adequate molecular accommodation of the analyte with the catalytic sites of the enzyme, which also preserved the asparaginase activity. This work then demonstrates the feasibility of employing LB films composed of fatty acids, CNT, and enzymes as devices for biosensing applications. (AU)

FAPESP's process: 19/03239-0 - Nanostructured interfaces for the investigation of bioactive substances in cell membrane models and for the construction of optoelectronic devices
Grantee:Luciano Caseli
Support Opportunities: Regular Research Grants