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Dihydroxynaphthalene-based mimicry of fungal melanogenesis for multifunctional coatings.

Jeon JR, Le TT, Chang YS - Microb Biotechnol (2016)

Bottom Line: This product, termed poly(2,7-DHN), was successfully deposited onto a wide variety of solid surfaces, including metals, polymeric materials, ceramics, biosurfaces and mineral complexes.The melanin-like polymerization could be used to co-immobilize other organic molecules, forming functional surfaces.Moreover, the novel physicochemical properties of the poly(2,7-DHN) illuminate its potential applications as bactericidal, radical-scavenging and pollutant-sorbing agents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Agriculture & Life Science, Gyeongsang National University, Jinju, 52727, Korea.

No MeSH data available.


Related in: MedlinePlus

FTIR‐ATR spectra of 2,7‐DHN‐coated A. CPP and B. PET.C. Radical scavenging and D. selective sorption behaviour of 2,7‐DHN‐derived polymer (photograph, left to right: malachite green (+); crystal violet (+); Remazol Brilliant Blue R (−); Bromophenol blue (−), top to down: control; poly(2,7‐DHN) treated).E. Anti‐bacterial (left to right: control; DHN‐derived polymer, top to down: 10−3; 10−2 dilution) activity and F. phenol content of 2,7‐DHN‐derived polymer.
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mbt212347-fig-0003: FTIR‐ATR spectra of 2,7‐DHN‐coated A. CPP and B. PET.C. Radical scavenging and D. selective sorption behaviour of 2,7‐DHN‐derived polymer (photograph, left to right: malachite green (+); crystal violet (+); Remazol Brilliant Blue R (−); Bromophenol blue (−), top to down: control; poly(2,7‐DHN) treated).E. Anti‐bacterial (left to right: control; DHN‐derived polymer, top to down: 10−3; 10−2 dilution) activity and F. phenol content of 2,7‐DHN‐derived polymer.

Mentions: To confirm that the poly(2,7‐DHN) bore multiple hydroxyphenyl groups, we employed several different experimental methods. Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) measurements were taken on poly(2,7‐DHN)‐coated PET and CPP surfaces. The coated layer gave peaks at 3200–3400 cm−1, corresponding to a high concentration of phenol groups (Fig. 3A and B). Also, since hydroxyphenyl groups have been linked to reactive radical scavenging and bactericidal activity, and such properties have been readily observed in polyphenolics derived from plant biomass (Wang and Ho, 2009; Daglia, 2012), we employed the 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐(sulfonic acid)) (ABTS) radical and Escherichia coli to determine whether the poly(2,7‐DHN) exhibits similar properties. The addition of poly(2,7‐DHN) particulates rapidly induced decolouration of the blue‐coloured ABTS radical, indicating that the radical was effectively scavenged (Fig. 3C). This finding is consistent with the in vivo physiological roles of fungal melanin in pathogenesis. The pigment present in the cell wall can contribute to reduction of the oxidative burst capacity of the host immune system via its reactive oxygen scavenging action (Jeon and Chang, 2013b). E. coli proliferation was also effectively inhibited in the presence of poly(2,7‐DHN) (Fig. 3E). These results both strongly support the hypothesis that poly(2,7‐DHN) consists of a hydroxyphenyl group‐bearing polyaromatic. Further evidence for this hypothesis was obtained from analysis of the charge‐dependent sorption behaviour of the polymer. The material was found to adsorb cationic dyes but not anionic dyes (Fig. 3D). This sorption pattern was attributed to non‐covalent interactions between the polymer and dye, with the hydroxyphenyl groups being transformed into negatively charged moieties or providing negative dipole moments that would interact preferentially with cationic organic molecules. Furthermore, the phenolic groups may exert a repulsive force on anionic species. The determined Zeta potential value of −2.51 mV (see Experimental section) of the poly(2,7‐DHN) also supported this preferred sorption of cationic charges. To achieve a more direct indication of the phenol content of poly(2,7‐DHN), a phenol‐reactive reagent (i.e. Folin‐Ciocalteu reagent) was employed, and a significant signal was observed, verifying the presence of phenolic groups (Fig. 3F).


Dihydroxynaphthalene-based mimicry of fungal melanogenesis for multifunctional coatings.

Jeon JR, Le TT, Chang YS - Microb Biotechnol (2016)

FTIR‐ATR spectra of 2,7‐DHN‐coated A. CPP and B. PET.C. Radical scavenging and D. selective sorption behaviour of 2,7‐DHN‐derived polymer (photograph, left to right: malachite green (+); crystal violet (+); Remazol Brilliant Blue R (−); Bromophenol blue (−), top to down: control; poly(2,7‐DHN) treated).E. Anti‐bacterial (left to right: control; DHN‐derived polymer, top to down: 10−3; 10−2 dilution) activity and F. phenol content of 2,7‐DHN‐derived polymer.
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mbt212347-fig-0003: FTIR‐ATR spectra of 2,7‐DHN‐coated A. CPP and B. PET.C. Radical scavenging and D. selective sorption behaviour of 2,7‐DHN‐derived polymer (photograph, left to right: malachite green (+); crystal violet (+); Remazol Brilliant Blue R (−); Bromophenol blue (−), top to down: control; poly(2,7‐DHN) treated).E. Anti‐bacterial (left to right: control; DHN‐derived polymer, top to down: 10−3; 10−2 dilution) activity and F. phenol content of 2,7‐DHN‐derived polymer.
Mentions: To confirm that the poly(2,7‐DHN) bore multiple hydroxyphenyl groups, we employed several different experimental methods. Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) measurements were taken on poly(2,7‐DHN)‐coated PET and CPP surfaces. The coated layer gave peaks at 3200–3400 cm−1, corresponding to a high concentration of phenol groups (Fig. 3A and B). Also, since hydroxyphenyl groups have been linked to reactive radical scavenging and bactericidal activity, and such properties have been readily observed in polyphenolics derived from plant biomass (Wang and Ho, 2009; Daglia, 2012), we employed the 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐(sulfonic acid)) (ABTS) radical and Escherichia coli to determine whether the poly(2,7‐DHN) exhibits similar properties. The addition of poly(2,7‐DHN) particulates rapidly induced decolouration of the blue‐coloured ABTS radical, indicating that the radical was effectively scavenged (Fig. 3C). This finding is consistent with the in vivo physiological roles of fungal melanin in pathogenesis. The pigment present in the cell wall can contribute to reduction of the oxidative burst capacity of the host immune system via its reactive oxygen scavenging action (Jeon and Chang, 2013b). E. coli proliferation was also effectively inhibited in the presence of poly(2,7‐DHN) (Fig. 3E). These results both strongly support the hypothesis that poly(2,7‐DHN) consists of a hydroxyphenyl group‐bearing polyaromatic. Further evidence for this hypothesis was obtained from analysis of the charge‐dependent sorption behaviour of the polymer. The material was found to adsorb cationic dyes but not anionic dyes (Fig. 3D). This sorption pattern was attributed to non‐covalent interactions between the polymer and dye, with the hydroxyphenyl groups being transformed into negatively charged moieties or providing negative dipole moments that would interact preferentially with cationic organic molecules. Furthermore, the phenolic groups may exert a repulsive force on anionic species. The determined Zeta potential value of −2.51 mV (see Experimental section) of the poly(2,7‐DHN) also supported this preferred sorption of cationic charges. To achieve a more direct indication of the phenol content of poly(2,7‐DHN), a phenol‐reactive reagent (i.e. Folin‐Ciocalteu reagent) was employed, and a significant signal was observed, verifying the presence of phenolic groups (Fig. 3F).

Bottom Line: This product, termed poly(2,7-DHN), was successfully deposited onto a wide variety of solid surfaces, including metals, polymeric materials, ceramics, biosurfaces and mineral complexes.The melanin-like polymerization could be used to co-immobilize other organic molecules, forming functional surfaces.Moreover, the novel physicochemical properties of the poly(2,7-DHN) illuminate its potential applications as bactericidal, radical-scavenging and pollutant-sorbing agents.

View Article: PubMed Central - PubMed

Affiliation: Institute of Agriculture & Life Science, Gyeongsang National University, Jinju, 52727, Korea.

No MeSH data available.


Related in: MedlinePlus