engleski

Interfacial characteristics of marine algae and bacteria using adhesion based electrochemical sensor

Mixtures of biopolymers and microbial cells are typical of natural aquatic environment such as seawater where they form biofilms at the interfaces and undergo aggregation. The electrochemical sensor that we have developed enables a distinction between cell adhesion and biopolymer adsorption. We study the adhesion of phytoplankton and bacteria in presence of adsorption of dissolved biopolymers at a model interface: seawater/dropping mercury electrode where the interfacial forces can be controlled by applied potential. Measuring parameters are frequency of cell adhesion, and the time of monolayer formation at the electrode surface. Upon impact of a D.tertiolecta cell with the interface a fast deformation occurs, followed by rupture of its fluid membrane and spreading of the cell content on the mercury surface. The electrical signal carries the information on all phases of the adhesion process starting from the initial molecular contact to the spreaded film. Marine bacteria adhere directly at the DME forming molecular contact, but because of rigid cell wall and the smaller size the adhesion signals of individual cells can not be resolved. We have demonstrated that the cell attachment and biopolymer adsorption occur simultaneously forming separated domaines in the initial film.

adhesion based electrochemical sensor; marine algae; marine bacteria

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