Free-standing polydopamine films generated in the presence of different metallic ions: the comparison of reaction process and film properties

Han, Xuwen; Tang, Feng; Jin, Zhaoxia

doi:10.1039/c8ra02930j

Cited by 37 publications

(23 citation statements)

References 43 publications

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“…43,46 Incorporation of nonelectroactive metal ions has been reported to shift the point of zero charge downward by approximately one pH unit, and the authors attributed this to a higher amount of pyrrolecarboxylic acids, although without further justification. 43 On the other hand, copper has been reported to bring about an opposite and larger change. 46 With the nanoparticles prepared using the redox-active metal ions in this work, the ζ potential in acidic solutions was more negative than that of the purely autoxidized ones (Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

“…If the autoxidation of dopamine is carried out in the presence of various nonoxidizing metal ions (Na + , Ca 2+ , Mg 2+ , Co 2+ ), the nanoparticle formation and their properties are affected. 43 Fentonlike chemistry using a mixture of Fe(II) and hydrogen peroxide leads to a rapid generation of polydopamine nanoparticles. 44 On the other hand, oxidation of dopamine by Cu(II) under anaerobic conditions is a very slow reaction.…”

Section: Introductionmentioning

confidence: 99%

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Polydopamine Nanoparticles Prepared Using Redox-Active Transition Metals

et al. 2019

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Autoxidation of dopamine to polydopamine by dissolved oxygen is a slow process that requires highly alkaline conditions. Polydopamine can be formed rapidly also in mildly acidic and neutral solutions by using redox-active transition-metal ions. We present a comparative study of polydopamine nanoparticles formed by autoxidation and aerobic or anaerobic oxidation in the presence of Ce(IV), Fe(III), Cu(II), and Mn(VII). The UV–vis spectra of the purified nanoparticles are similar, and dopaminechrome is an early intermediate species. At low pH, Cu(II) requires the presence of oxygen and chloride ions to produce polydopamine at a reasonable rate. The changes in dispersibility and surface charge take place at around pH 4, which indicates the presence of ionizable groups, especially carboxylic acids, on their surface. X-ray photoelectron spectroscopy shows the presence of three different classes of carbons, and the carbonyl/carboxylate carbons amount to 5–15 atom %. The N 1s spectra show the presence of protonated free amino groups, suggesting that these groups may interact with the π-electrons of the intact aromatic dihydroxyindole moieties, especially in the metal-induced samples. The autoxidized and Mn(VII)-induced samples do not contain metals, but the metal content is 1–2 atom % in samples prepared with Ce(IV) or Cu(II), and ca. 20 atom % in polydopamine prepared in the presence of Fe(III). These differences in the metal content can be explained by the oxidation and complexation properties of the metals using the general model developed. In addition, the nitrogen content is lower in the metal-induced samples. All of the metal oxidants studied can be used to rapidly prepare polydopamine at room temperature, but the possible influence of the metal content and nitrogen loss should be taken into account.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polydopamine Nanoparticles Prepared Using Redox-Active Transition Metals

et al. 2019

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“…Freestanding PDA films with a thickness of several hundreds of nanometers or even micrometers have been synthesized before. [ 20–27 ] Ultrathin and homogeneous PDA films attached to gold surfaces with thicknesses of 5–20 nm have been prepared by electropolymerization. [ 28 ] Electropolymerization is considerably faster than the often applied dip coating procedure, allowing precise control of the film thickness and homogeneity.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin Polydopamine Films with Phospholipid Nanodiscs Containing a Glycophorin A Domain

D'Alvise

Harvey

Hueske

et al. 2020

Adv Funct Materials

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Cellular membranes have long served as an inspiration for nanomaterial research. The preparation of ultrathin polydopamine (PDA) films with integrated protein pores containing phospholipids and an embedded domain of a membrane protein glycophorin A as simplified cell membrane mimics is reported. Large area, ultrathin PDA films are obtained by electropolymerization on gold surfaces with 10-18 nm thickness and dimensions of up to 2.5 cm 2 . The films are transferred from gold to various other substrates such as nylon mesh, silicon, or substrates containing holes in the micrometer range, and they remain intact even after transfer. The novel transfer technique gives access to freestanding PDA films that remain stable even at the air interfaces with elastic moduli of ≈6-12 GPa, which are higher than any other PDA films reported before. As the PDA film thickness is within the range of cellular membranes, monodisperse protein nanopores, so-called "nanodiscs," are integrated as functional entities. These nanodisc-containing PDA films can serve as semipermeable films, in which the embedded pores control material transport. In the future, these simplified cell membrane mimics may offer structural investigations of the embedded membrane proteins to receive an improved understanding of protein-mediated transport processes in cellular membranes.

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“…Polydopamine films formed at the air-water interface have attracted less attention [16,[23][24][25][26] as compared with the films on a solid substrate [27,28]. The application of pendant drop tensiometry showed that the surface tension decreased to 53 mN/m at a concentration of 2 g/l and to 10 mN/m at a concentration of 10 g/l [24].…”

Section: Introductionmentioning

confidence: 99%

“…Besides, the polydopamine film is far more extended than a monolayer, and one can measure only some effective surface tension, which can depend on the measurement method [29,30]. Even so, such films are characterized by weak durability, which can be improved by the addition of different agents such as urea, pyrochatechol, alginate catechol [25], poly(ethylene imine) [31], and metal ions [26]. Polymers work like cross-linkers creating covalent bonds between isolated polydopamine clusters.…”

Section: Introductionmentioning

confidence: 99%

Polydopamine layer formation at the liquid – gas interface

Milyaeva

Bykov

Campbell

et al. 2019

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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The surface properties of a polydopamine layer at the air-water interface were studied by dilatational surface rheology, ellipsometry and Brewster angle microscopy (BAM). A significant increase of the dynamic surface elasticity was discovered when the concentration changed from 0.75 g/l to 2 g/l with the maximum value of about 60 mN/m at a concentration of 1 g/l. The obtained results indicate that the surface film consists of separate domains and the high surface elasticity is a consequence of the interactions between relatively rigid domains of the polymer film. This conclusion was confirmed by Brewster angle microscopy, which demonstrated different steps of the polydopamine film growth. Separate domains appeared at the first step while one can observe a continuous film close to equilibrium. An increase of the initial concentration led to faster polymerization and to the formation of a thicker film. The dynamic surface elasticity decreased in the concentration range from 2 g/l to 5 g/l when the thickness of the polymer film reached about 80 nm. In this case the film could be destroyed in the course of deformation. The cracks in the film resulted in a decrease of the dynamic surface elasticity.

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Free-standing polydopamine films generated in the presence of different metallic ions: the comparison of reaction process and film properties

Abstract: Different stratification processes lead to different morphologies of films generated with various cations.

Cited by 37 publications

References 43 publications

Polydopamine Nanoparticles Prepared Using Redox-Active Transition Metals

Polydopamine Nanoparticles Prepared Using Redox-Active Transition Metals

Ultrathin Polydopamine Films with Phospholipid Nanodiscs Containing a Glycophorin A Domain

Polydopamine layer formation at the liquid – gas interface

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