Interação da enzima lactase em filmes fosfolipídicos de Langmuir e Langmuir-Blodgett: possível aplicação para biossensores para lactose

• Ano de defesa: 2017
• Autor(a) principal: Ayoub, Fabio de Paula [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: LB films; Lactase; Biossensors; Interface; Monolayer; Filmes LB; Biossensores; Monocamadas
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5539914; http://repositorio.unifesp.br/handle/11600/49916

In this work the interaction of the enzyme lactase in Langmuir and Langmuir-Blodgett (LB) films of the phospholipid dimyristoylphosphatidic acid (DMPA) was studied. The phospholipid was spread at the air-water interface forming Langmuir monolayers, and the enzyme was inserted into the aqueous subphase that supported the lipid monolayer. The adsorption of the enzyme to the monolayer was studied by surface pressure-area isotherms, surface potential-area isotherms, Brewster angle microscopy, and by vibrational spectroscopy. The mixed monolayers phospholipid + enzyme was transferred to solid supports by the LB methodology and characterized by luminescence spectroscopy, vibrational spectroscopy, atomic force microscopy and nanogravimmetry by quartz crystal microbalance. The enzymatic activity of the lactase immobilized as LB film was evaluated and compared to the hydrolysis of lactose to glucose and galactose using UV-visible spectroscopy. As conclusion, the enzyme can be inserted into the lipid films, maintaining partially its secondary structures, and altering the morphology of the LB films. The catalytic activity could be maintained up to 84% of the activity in relation to the homogeneous medium, which makes the system feasible for future applications in lactose biosensors.