Copolymerization of a Catechol and a Diamine as a Versatile Polydopamine-Like Platform for Surface Functionalization: The Case of a Hydrophobic Coating

Suárez-García, Salvio; Sedó, Josep; Saiz‐Poseu, Javier; Ruiz‐Molina, Daniel

doi:10.3390/biomimetics2040022

“…21,[23][24][25][26][27] Although polydopamine receives a lot of attention, it is clear that one should not limit themselves to the use of dopamine as the catecholic precursor for developing adhesive materials. [28][29][30] In recent years we have presented various studies on the air-or reactive oxygen species-mediated oxidation of various catecholic compounds into dark-or light-colored pigments. [31][32][33][34][35][36][37][38] This report presents our first attempt to generate pheomelanin-like pigments by including L-cysteine into the reaction mixtures.…”

Section: Scheme 1: Basic Outline Of the Biosynthesis Of Eumelanin Andmentioning

confidence: 99%

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Vercruysse

¹

,

Govan²

2019

Preprint

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We investigated the synthesis of melanin-like materials from DOPA, dopamine, norepinephrine and epinephrine in the presence of L-cysteine. We observed that L-cysteine delayed the formation of pigment from these catecholamines and that the presence of L-cysteine yielded darker-colored reaction mixtures. No reddish pigment was observed that would indicate the synthesis of pheomelanin-like material. The reactions were performed in the presence of Na2CO3 and through the addition of CaCl2 at the end of the reaction; the black, eumelanin-like material was co-precipitated with CaCO3. The remaining supernatant solutions were observed to be light-yellow to rusty-orange in color depending on the catecholamine used in the reaction. Size exclusion chromatography (SEC) analyses indicated that the removal of the black pigment left behind an oligomeric material that exhibited a strong absorbance band around 280nm. Our experimental and analytical observations prompt us to raise a number of points of discussion or hypotheses. 1) The presence of L-cysteine during the air-mediated oxidation of catecholamines leads to darker-colored pigments; not reddish or lighter-colored pigments that would visually resemble pheomelanin-like pigments, 2) SEC analyses suggested that the black pigment generated during the air-mediated oxidation of catecholamines is not necessarily the main reaction product, 3) The pre-formed, dark-colored pigments obtained through the air-mediated oxidative melanogenesis process can readily be deposited on insoluble mineral surfaces using an in situ co-precipitation procedure, 4) The air-mediated oxidation of catecholamines leads to a binary product that contains an insoluble, melanin-like substance and a soluble, oligo- or polymeric substance containing unoxidized precursor units, 5) The melanogenesis process leads to a binary product involving a non-covalently bonded combination of dark-colored pigment and a lighter-colored or colorless substance; the latter being understudied or ignored in the in vitro or in vivo studies of the melanogenesis process, 6) The kinetics of the melanogenesis process may determine the balance between insoluble and soluble components of the binary product generated; the slower the reaction the more dark-colored, insoluble pigment generated, 7) One should consider the possibility of intermolecularly, N-to-C, bonded units of catecholamines when evaluating the structure of melanins, polydopamines, etc. and 8) There is a need for a systematic study of the effect of amino acids (beyond just L-cysteine) and amines in general on the melanogenesis process.

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“…21,[23][24][25][26][27] Although polydopamine receives a lot of attention, it is clear that one should not limit themselves to the use of dopamine as the catecholic precursor for developing adhesive materials. [28][29][30] In recent years we have presented various studies on the air-or reactive oxygen species-mediated oxidation of various catecholic compounds into dark-or light-colored pigments. [31][32][33][34][35][36][37][38] This report presents our first attempt to generate pheomelanin-like pigments by including L-cysteine into the reaction mixtures.…”

Section: Scheme 1: Basic Outline Of the Biosynthesis Of Eumelanin Andmentioning

confidence: 99%

“…52 The reactivity between catechols and amines is exploited in the development of multifunctional coatings through a reaction between a catechol and diamine species. 28,30,53,54 One should consider the possibility of intermolecularly, N-to-C, bonded units of catecholamines when evaluating the structure of melanins, polydopamines, etc.…”

Section: Scheme 2: Comparison Between the Intra-and Intermolecular Sumentioning

confidence: 99%

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Vercruysse¹,

Govan²

2019

Preprint

View full text Add to dashboard Cite

We investigated the synthesis of melanin-like materials from DOPA, dopamine, norepinephrine and epinephrine in the presence of L-cysteine. We observed that L-cysteine delayed the formation of pigment from these catecholamines and that the presence of L-cysteine yielded darker-colored reaction mixtures. No reddish pigment was observed that would indicate the synthesis of pheomelanin-like material. The reactions were performed in the presence of Na2CO3 and through the addition of CaCl2 at the end of the reaction; the black, eumelanin-like material was co-precipitated with CaCO3. The remaining supernatant solutions were observed to be light-yellow to rusty-orange in color depending on the catecholamine used in the reaction. Size exclusion chromatography (SEC) analyses indicated that the removal of the black pigment left behind an oligomeric material that exhibited a strong absorbance band around 280nm. Our experimental and analytical observations prompt us to raise a number of points of discussion or hypotheses. 1) The presence of L-cysteine during the air-mediated oxidation of catecholamines leads to darker-colored pigments; not reddish or lighter-colored pigments that would visually resemble pheomelanin-like pigments, 2) SEC analyses suggested that the black pigment generated during the air-mediated oxidation of catecholamines is not necessarily the main reaction product, 3) The pre-formed, dark-colored pigments obtained through the air-mediated oxidative melanogenesis process can readily be deposited on insoluble mineral surfaces using an in situ co-precipitation procedure, 4) The air-mediated oxidation of catecholamines leads to a binary product that contains an insoluble, melanin-like substance and a soluble, oligo- or polymeric substance containing unoxidized precursor units, 5) The melanogenesis process leads to a binary product involving a non-covalently bonded combination of dark-colored pigment and a lighter-colored or colorless substance; the latter being understudied or ignored in the in vitro or in vivo studies of the melanogenesis process, 6) The kinetics of the melanogenesis process may determine the balance between insoluble and soluble components of the binary product generated; the slower the reaction the more dark-colored, insoluble pigment generated, 7) One should consider the possibility of intermolecularly, N-to-C, bonded units of catecholamines when evaluating the structure of melanins, polydopamines, etc. and 8) There is a need for a systematic study of the effect of amino acids (beyond just L-cysteine) and amines in general on the melanogenesis process.

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“…In the FT-IR spectrum for nanoparticles coated with PDA (Fe3O4/PDA), the band characteristic of PDA appears at 1286 cm −1 , attributed to phenolic hydroxyl groups [30]. The band at 1634 cm −1 becomes broad due to presence of C=O [31,32]. The peak at 1485 cm −1 was associated with C=C in aromatic rings [33], confirming the modification was successful.…”

Section: Fourier-transform Infrared Spectroscopy (Ft-ir)mentioning

confidence: 90%

Enhancement of GAD Storage Stability with Immobilization on PDA-Coated Superparamagnetic Magnetite Nanoparticles

Zafar

¹

,

Wang

²

,

Lv

³

et al. 2019

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To improve the storage stability of glutamic acid decarboxylase (GAD), superparamagnetic magnetite (Fe3O4) nanoparticles were synthesized by co-precipitation method and coated with polydopamine (PDA) for GAD immobilization. Dynamic light scattering and transmission electron microscopy were used to determine size of the nanoparticles, which were approximately 10 nm, increasing to 15 nm after PDA-coating and to 20 nm upon GAD binding. Vibrational scanning measurements significantly represented the superparamagnetic behavior of the Fe3O4, and X-ray diffraction analysis confirmed that the crystalline structure before and after coating with PDA and the further immobilization of GAD remained the same. Thermogravimetric analysis and Fourier-transform infrared spectroscopy proved that the PDA-coating on Fe3O4 and further immobilization of GAD were successful. After immobilization, the enzyme can be used with a relative specific activity of 40.7% after five successive uses. The immobilized enzyme retained relative specific activity of about 50.5% after 15 days of storage at 4 °C, while free enzyme showed no relative specific activity after two days of storage. The GAD immobilization on PDA-coated magnetite nanoparticles was reported for the improvement of enzyme storage stability for the first time.

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Copolymerization of a Catechol and a Diamine as a Versatile Polydopamine-Like Platform for Surface Functionalization: The Case of a Hydrophobic Coating

Cited by 35 publications

References 49 publications

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Melanogenesis: A Search for Pheomelanin and Also, What Is Lurking Behind Those Dark Colors?

Enhancement of GAD Storage Stability with Immobilization on PDA-Coated Superparamagnetic Magnetite Nanoparticles

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