title: Using phospholipid Langmuir and Langmuir-Blodgett films as matrix for urease immobilization.
abstract: The immobilization of enzymes in organized two-dimensional matrices is a key requirement for many biotechnological applications. In this paper, we used the Langmuir-Blodgett (LB) technique to obtain controlled architectures of urease immobilized in solid supports, whose physicochemical properties were investigated in detail. Urease molecules were adsorbed at the air-water interface and incorporated into Langmuir monolayers of the phospholipid dipalmitoyl phosphatidyl glycerol (DPPG). Incorporation of urease made DPPG monolayers more flexible and caused the reduction of the equilibrium and dynamic elasticity of the film. Urease and DPPG-urease mixed monolayers could be transferred onto solid substrates, forming LB films. A close packing arrangement of urease was obtained, especially in the mixed LB films, which was inferred with nanogravimetry and electrochemistry measurements. From the blocking effect of the LB films deposited onto indium tin oxide (ITO) substrates, the electrochemical properties of the LB films pointed to a charge transport controlled by the lipid architecture.
authors: Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, São Paulo, Brazil. lcaseli@usp.br
authors: Luciano
authors: L
authors: Caseli
authors: Frank N
authors: FN
authors: Crespilho
authors: Thatyane M
authors: TM
authors: Nobre
authors: Maria Elisabete D
authors: ME
authors: Zaniquelli
authors: Valtencir
authors: V
authors: Zucolotto
authors: Osvaldo N
authors: ON
authors: Oliveira
mesh_terms: D000327:Adsorption; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D044367:Phase Transition; D010715:Phosphatidylglycerols / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D013499:Surface Properties; D014510:Urease / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D010715:Phosphatidylglycerols; D010743:Phospholipids; D014510:Urease; C030345:1,2-dipalmitoylphosphatidylglycerol