Algal polysaccharides as matrices for the immobilization of urease in lipid ultrathin films studied with tensiometry and vibrational spectroscopy: Physical-chemical properties and implications in the enzyme activity

Autor(es)

de Brito, Audrey Kalinouski ^[1] ; Nordi, Cristina S. F. ^[1] ; Caseli, Luciano ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, UNIFESP, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 135, p. 639-645, NOV 1 2015.
• Citações Web of Science: 10

Resumo

Currently, many biological substances extracted from algae have received special attention because of their intrinsic characteristics, which can be applied to different areas of biotechnology. Therefore, in the current study, exopolysaccharides (EPS) from the microalgae Cryptomonas tetrapirenoidosa were employed as an aqueous subphase of a monolayer formed by the lipid dioctadecyldimethylammonium bromide (DODAB). The primary objective of this approach was to evaluate whether EPS could serve as a matrix for the immobilization of the enzyme urease to produce biosensors for urea. After DODAB was spread on the EPS solutions, urease was injected into the aqueous subphase, and the surface was submitted to compression using lateral barriers. The monolayers were subsequently characterized by surface pressure-area isotherms and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). The results indicated that EPS enhanced the adsorption of the enzyme on the lipid monolayer. The mixed films were later transferred to solid supports using the Langmuir-Blodgett (LB) technique and were characterized by transfer ratio, PM-IRRAS, quartz crystal microbalance, and atomic force microscopy. The immobilization of the enzyme on solid supports was fundamental for providing an ideal geometrical accommodation of urease because the interaction of EPS with urease in solution causes a decrease of the relative activity of urease. Therefore, these LB films are promising for the fabrication of future urea biosensors, the architecture of which can be manipulated and enhanced at the molecular level. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 11/14289-7 - Adsorção de metais poluentes e enzimas em filmes híbridos de Langmuir-Blodgett imobilizados com polissacarídeos algais/fosfolipídios
• Beneficiário: Audrey Kalinouski de Brito
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 13/10213-1 - Interação de materiais bioativos em filmes ultrafinos organizados em modelos de biointerfaces para investigação de processos de reconhecimento molecular e mecanismos moleculares associados
• Beneficiário: Luciano Caseli
• Modalidade de apoio: Auxílio à Pesquisa - Regular