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Surface functionalization by covalent immobilization of an innovative carvacrol derivative to avoid fungal biofilm formation.

Gharbi A, Legigan T, Humblot V, Papot S, Berjeaud JM - AMB Express (2015)

Bottom Line: On the contrary, when a phenyl group replaced the terpenic moiety, the yeast culturability increased by about 30%, highlighting the specific activity of carvacrol grafted on the surfaces.Confocal microscopy analyses showed that the mode of action of the functionalized surfaces with the ester or the ether of carvacrol was, in both cases, fungicidal and not anti-adhesive.Finally, this study shows that covalently immobilization of terpenic compounds can be used to design promising antimicrobial surfaces.

View Article: PubMed Central - PubMed

Affiliation: Ecologie & Biologie des Interactions - UMR CNRS 7267, Microbiologie de l'eau, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073 Poitiers Cedex 9, France.

ABSTRACT
Carvacrol, an aromatic terpenic compound, known to be antimicrobial was grafted onto gold surfaces via two strategies based on newly-synthesized cross-linkers involving either an ester bond which can be cleaved by microbial esterases, or a covalent ether link. Surface functionalizations were characterized at each step by reflection absorption infrared spectroscopy (RAIRS). The two functionalized gold samples both led to a loss of culturability of the yeast Candida albicans, higher than 65%, indicating that the activity of the freshly-designed surfaces was probably due to still covalently immobilized carvacrol. On the contrary, when a phenyl group replaced the terpenic moiety, the yeast culturability increased by about 30%, highlighting the specific activity of carvacrol grafted on the surfaces. Confocal microscopy analyses showed that the mode of action of the functionalized surfaces with the ester or the ether of carvacrol was, in both cases, fungicidal and not anti-adhesive. Finally, this study shows that covalently immobilization of terpenic compounds can be used to design promising antimicrobial surfaces.

No MeSH data available.


Viability of adherentC. albicansATCC 3153, revealed by BacLight™ stain, attached to gold surfaces grafted with MUA (A) or with EstC-NH2(B) observed by confocal microscopy (magnification × 20). 106 Candida cells were deposited on the samples and allowed to adhere for 3 h.
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Fig5: Viability of adherentC. albicansATCC 3153, revealed by BacLight™ stain, attached to gold surfaces grafted with MUA (A) or with EstC-NH2(B) observed by confocal microscopy (magnification × 20). 106 Candida cells were deposited on the samples and allowed to adhere for 3 h.

Mentions: Confocal microscopy analyses were carried out using BacLight™ staining. Briefly, the cellular membrane of the yeasts which appeared red is damaged, whereas green cells have maintained their integrity and are considered as alive. Indeed, the red stain (PI) can only penetrate permeabilized cells, whereas the green one (Syto9) can cross over intact cellular membranes. Images obtained by confocal microscopy analyses are presented in Figure 5. Entire surfaces of three samples of each type of substrate were analysed. On the control surface, grafted with MUA only, C. albicans ATCC 3153 cells appeared as small green clusters corresponding to living yeasts (Figure 5A). As the yeast density differs according to the surface area that is observed under the microscope, several pictures were taken on the same surface and a mean density of each type of stained cells, red and green, was calculated for each surface after having manually counted both Syto9- and PI-stained cells. On the surface functionalized with EstC-NH2, the number of total adherent cells was similar to the control Au-MUA but the number of red permeabilized and probably dead cells, increased by 60% comparing to the same control (Figure 4A and Figure 5B) (n = 2).Figure 5


Surface functionalization by covalent immobilization of an innovative carvacrol derivative to avoid fungal biofilm formation.

Gharbi A, Legigan T, Humblot V, Papot S, Berjeaud JM - AMB Express (2015)

Viability of adherentC. albicansATCC 3153, revealed by BacLight™ stain, attached to gold surfaces grafted with MUA (A) or with EstC-NH2(B) observed by confocal microscopy (magnification × 20). 106 Candida cells were deposited on the samples and allowed to adhere for 3 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384722&req=5

Fig5: Viability of adherentC. albicansATCC 3153, revealed by BacLight™ stain, attached to gold surfaces grafted with MUA (A) or with EstC-NH2(B) observed by confocal microscopy (magnification × 20). 106 Candida cells were deposited on the samples and allowed to adhere for 3 h.
Mentions: Confocal microscopy analyses were carried out using BacLight™ staining. Briefly, the cellular membrane of the yeasts which appeared red is damaged, whereas green cells have maintained their integrity and are considered as alive. Indeed, the red stain (PI) can only penetrate permeabilized cells, whereas the green one (Syto9) can cross over intact cellular membranes. Images obtained by confocal microscopy analyses are presented in Figure 5. Entire surfaces of three samples of each type of substrate were analysed. On the control surface, grafted with MUA only, C. albicans ATCC 3153 cells appeared as small green clusters corresponding to living yeasts (Figure 5A). As the yeast density differs according to the surface area that is observed under the microscope, several pictures were taken on the same surface and a mean density of each type of stained cells, red and green, was calculated for each surface after having manually counted both Syto9- and PI-stained cells. On the surface functionalized with EstC-NH2, the number of total adherent cells was similar to the control Au-MUA but the number of red permeabilized and probably dead cells, increased by 60% comparing to the same control (Figure 4A and Figure 5B) (n = 2).Figure 5

Bottom Line: On the contrary, when a phenyl group replaced the terpenic moiety, the yeast culturability increased by about 30%, highlighting the specific activity of carvacrol grafted on the surfaces.Confocal microscopy analyses showed that the mode of action of the functionalized surfaces with the ester or the ether of carvacrol was, in both cases, fungicidal and not anti-adhesive.Finally, this study shows that covalently immobilization of terpenic compounds can be used to design promising antimicrobial surfaces.

View Article: PubMed Central - PubMed

Affiliation: Ecologie & Biologie des Interactions - UMR CNRS 7267, Microbiologie de l'eau, Université de Poitiers, 1 Rue Georges Bonnet, TSA 51106, 86073 Poitiers Cedex 9, France.

ABSTRACT
Carvacrol, an aromatic terpenic compound, known to be antimicrobial was grafted onto gold surfaces via two strategies based on newly-synthesized cross-linkers involving either an ester bond which can be cleaved by microbial esterases, or a covalent ether link. Surface functionalizations were characterized at each step by reflection absorption infrared spectroscopy (RAIRS). The two functionalized gold samples both led to a loss of culturability of the yeast Candida albicans, higher than 65%, indicating that the activity of the freshly-designed surfaces was probably due to still covalently immobilized carvacrol. On the contrary, when a phenyl group replaced the terpenic moiety, the yeast culturability increased by about 30%, highlighting the specific activity of carvacrol grafted on the surfaces. Confocal microscopy analyses showed that the mode of action of the functionalized surfaces with the ester or the ether of carvacrol was, in both cases, fungicidal and not anti-adhesive. Finally, this study shows that covalently immobilization of terpenic compounds can be used to design promising antimicrobial surfaces.

No MeSH data available.