Tunable, Metal-Loaded Polydopamine Nanoparticles Analyzed by Magnetometry

Abstract

We report the preparation and study of Mn(III)-, Fe(III)-, Co(II)-, Ni(II)-, Cu(II)-, Zn(II)-, and Ga(III)-loaded polydopamine nanoparticles (PDA-NPs) via autoxidation polymerization of metal−dopamine complexes in the presence of free dopamine. An analysis of the doping range and parameters that influence final particle morphology is presented. In addition, magnetometry provides a probe of the general electronic structure and electronic interactions for Mn(III)-, Ni(II)-, and Co(II)-loaded PDA-NPs. PDA-NPs doped with Mn(III) are found to have high spin, low anisotropy, and weak magnetic coupling and are therefore predicted to have superior relaxivity behavior compared to previously studied Fe(III)-loaded PDA-NPs. Comparison of Mn(III)-and Fe(III)-loaded PDA-NP relaxivity confirms the predictive ability of the magnetometry measurements.

High Relaxivity Gadolinium‐Polydopamine Nanoparticles

“…MnPD‐NPs were prepared through the oxidative polymerization of dopamine in the presence of Mn(III) salts under basic conditions as previously reported. [15a] We initially observe a red solution suggesting the formation of an Mn(III)‐catecholate species,[15b] which is polymerized to form black MnPD‐NPs. The incorporation of Mn can be confirmed by X‐ray photoelectron spectroscopy (XPS).…”

“…Recent magnetometry studies on materials prepared via this method for MnPD‐NPs have corroborated the trivalent oxidation state, likely due to the highly oxidative conditions of the polymerization. [15a]…”

“…Therefore, we hypothesize that the Mn(III) was replaced by Gd(III) due to weaker binding of Mn(III) to polydopamine compared with Gd(III). [15c] These GdPD‐NPs were characterized by TEM and DLS with no change in morphology compared to the initial MnPD‐NP species (Figure d and Figures S1 and S2 and Table S1, Supporting Information). In addition, by choosing templates with increased amounts of Mn(III), we can achieve higher Gd loadings of up to 17 wt% (Table S1, Supporting Information).…”

Mussel inspired green synthesis of silver nanoparticles-decorated halloysite nanotube using dopamine: characterization and evaluation of its catalytic activity

“…Hence based on the observation, it can be implied that 5 mM (HNTAg5 nanocomposite) is the optimum concentration of AgNO 3 for catalytic reduction of 4-NP in the presence of NaBH 4 . The variation of rate constant of nanocomposites mainly depends on the size of the nanoparticles, amount of nanoparticles formed and aggregation of them which directly related to the synthesis parameters such as reaction time, concentration of reducing agent (here PDA), pH of the medium and molar ratio of reducing agent to metal salts added as precursor for nanoparticles (Wang et al 2017). During the synthesis of AgNPs in our work, as all other synthesis parameters are kept fixed except molar ratio of reducing agent to metal salt, it can affect morphology of the synthesized AgNPs over HNTs surface.…”

Phenolische Bausteine für die Assemblierung von Funktionsmaterialien

“…100 nm konnten mit großen Wirkstoffmengen beladen werden und zeigten geringe “Fouling”‐Eigenschaften. in einer weiteren aktuellen Studie wurde eine Reihe von metallbeladenen PDA‐Nanopartikeln durch oxidative Selbstpolymerisation von Metall‐Dopamin‐Komplexen in Gegenwart von freiem Dopamin erhalten . Die Mn III ‐beladenen PDA‐Nanopartikel hatten dabei einen hohen Spin, eine geringe Anisotropie und eine schwache magnetische Kopplung und damit ein überlegenes Relaxitätsverhalten im Vergleich zu Fe III ‐beladenen PDA‐Nanopartikeln …”