ABSTRACT
We report a straightforward route for the preparation of flexible, electrochemically stable and easily functionalizable poly(3,4-ethylenedioxythiophene) (PEDOT) composite films deposited on PET foils as biosensing platforms. For this purpose, poly(allylamine) hydrochloride (PAH) was blended with PEDOT to provide amine-bearing sites for further biofunctionalization as well as to improve the mechanical properties of the films. The conducting PEDOT-PAH composite films were characterized by cyclic voltammetry, UV-vis and Raman spectroscopies. An exhaustive stability study was carried out from the mechanical, morphological and electrochemical viewpoint. Subsequent sugar functionalization of the available amine groups from PAH allowed for the specific recognition of lectins and the subsequent self-assembly of glycoenzymes (glucose oxidase and horseradish peroxidase) concomitant with the prevention of non-specific protein fouling. The platforms presented good bioelectrochemical performance (glucose oxidation and hydrogen peroxide reduction) in the presence of redox mediators. The developed composite films constitute a promising option for the construction of all-polymer biosensing platforms with great potential owing to their flexibility, high transmittance, electrochemical stability and the possibility of glycosylation, which provides a simple route for specific biofunctionalization as well as an effective antifouling strategy.
Subject(s)
Aspergillus niger/enzymology , Biosensing Techniques , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Electrochemical Techniques , Fungal Proteins/chemistry , Glucose Oxidase/chemistry , Glucose/analysis , Membranes, Artificial , Polyamines/chemistry , Polymers/chemistry , Horseradish Peroxidase/chemistryABSTRACT
Background: Marine ecosystems contain benthic microalgae and bacterial species that are capable of secreting extracellular polymeric substances (EPS), suggesting that settlement of these microorganisms can occur on submerged surfaces, a key part of the first stage of biofouling. Currently, anti-fouling treatments that help control this phenomenon involve the use of biocides or antifouling paints that contain heavy metals, which over a long period of exposure can spread to the environment. The bacterium Alteromonas sp. Ni1-LEM has an inhibitory effect on the adhesion of Nitzschia ovalis, an abundant diatom found on submerged surfaces. Results: We evaluated the effect of the bioactive compound secreted by this bacterium on the EPS of biofilms and associated epiphytic bacteria. Three methods of EPS extraction were evaluated to determine the most appropriate and efficient methodology based on the presence of soluble EPS and the total protein and carbohydrate concentrations. Microalgae were cultured with the bacterial compound to evaluate its effect on EPS secretion and variations in its protein and carbohydrate concentrations. An effect of the bacterial supernatant on EPS was observed by assessing biofilm formation and changes in the concentration of proteins and carbohydrates present in the biofilm. Conclusions: These results indicate that a possible mechanism for regulating biofouling could be through alteration of biofilm EPS and alteration of the epiphytic bacterial community associated with the microalga.
Subject(s)
Diatoms , Biofilms , Microalgae , Extracellular Polymeric Substance Matrix , Marine Environment , Biofouling , Metagenomics , MicrobiotaABSTRACT
The crude organic extracts of the endemic gorgonian Phyllogorgia dilatata and two sponge species Aplysina fulva and Mycale microsigmatosa were evaluated for anti-fouling properties through field experiments. To investigate this property in ecologically meaningful conditions, crude extracts from these invertebrates were incorporated at concentrations naturally found in these marine organisms into a stable gel used as a substratum for fouling settlement. Crude extract from A. fulva showed no significant anti-fouling property at the natural concentrations used in the field experiments. In fact, fouling organisms settled significantly more on gels treated with A. fulva extract than on the control gel. On the other hand, both M. microsigmatosa and P. dilatata yielded crude extracts that exhibited a selective action inhibiting only the settlement of barnacles. The evidences obtained here by means of field experiments can provide a basis for future development of one kind of natural antifoulant technology to prevent marine biofouling.
As propriedades antiincrustantes dos extratos brutos da gorgônia endêmica Phyllogorgia dilatata e de duas espécies de esponja, Aplysina fulva e Mycale microsigmatosa, foram avaliadas por intermédio de ensaios de campo. Para investigar essas propriedades sob condições ecologicamente relevantes, as concentrações naturais dos extratos brutos encontrados nesses invertebrados foram incorporadas a um gel estável que serviu de substrato para o assentamento de organismos incrustantes. O extrato bruto de A. fulva não mostrou efeito antiincrustante na concentração natural usada nos experimentos. De fato, os organismos incrustantes colonizaram significativamente mais o gel contendo extrato de A. fulva do que o gel-controle. Por outro lado, ambos os invertebrados, M. microsigmatosa e P. dilatata, produzem extratos brutos que foram seletivamente ativos contra o estabelecimento de balanídeos. As evidências obtidas aqui, por meio de experimentos em campo, podem ser importantes subsídios para futuras investigações visando à aplicação industrial de produtos naturais antiincrustantes em tecnologias de prevenção da bioincrustação marinha.
ABSTRACT
The crude organic extracts of the endemic gorgonian Phyllogorgia dilatata and two sponge species Aplysina fulva and Mycale microsigmatosa were evaluated for anti-fouling properties through field experiments. To investigate this property in ecologically meaningful conditions, crude extracts from these invertebrates were incorporated at concentrations naturally found in these marine organisms into a stable gel used as a substratum for fouling settlement. Crude extract from A. fulva showed no significant anti-fouling property at the natural concentrations used in the field experiments. In fact, fouling organisms settled significantly more on gels treated with A. fulva extract than on the control gel. On the other hand, both M. microsigmatosa and P. dilatata yielded crude extracts that exhibited a selective action inhibiting only the settlement of barnacles. The evidences obtained here by means of field experiments can provide a basis for future development of one kind of natural antifoulant technology to prevent marine biofouling.
As propriedades antiincrustantes dos extratos brutos da gorgônia endêmica Phyllogorgia dilatata e de duas espécies de esponja, Aplysina fulva e Mycale microsigmatosa, foram avaliadas por intermédio de ensaios de campo. Para investigar essas propriedades sob condições ecologicamente relevantes, as concentrações naturais dos extratos brutos encontrados nesses invertebrados foram incorporadas a um gel estável que serviu de substrato para o assentamento de organismos incrustantes. O extrato bruto de A. fulva não mostrou efeito antiincrustante na concentração natural usada nos experimentos. De fato, os organismos incrustantes colonizaram significativamente mais o gel contendo extrato de A. fulva do que o gel-controle. Por outro lado, ambos os invertebrados, M. microsigmatosa e P. dilatata, produzem extratos brutos que foram seletivamente ativos contra o estabelecimento de balanídeos. As evidências obtidas aqui, por meio de experimentos em campo, podem ser importantes subsídios para futuras investigações visando à aplicação industrial de produtos naturais antiincrustantes em tecnologias de prevenção da bioincrustação marinha.