Multifunctional Magnetic Nanochains: Exploiting Self-Polymerization and Versatile Reactivity of Mussel-Inspired Polydopamine

Abstract

We present a new strategy, built upon the use of mussel-inspired polydopamine (PDA), for constructing multifunctional nanochains of magnetic nanoparticles. One key finding is that self-polymerization of PDA around magnetically aligned nanoparticles affords robust rigid magnetic nanochains with versatile reactivity imparted by PDA. In particular, we have shown that loading of metal nanoparticles on the nanochains via localized reduction by PDA gave rise to magnetically recyclable, self-mixing nanocatalysts. Surface coupling of PDA with nucleophilic thiol and amine groups via Michael addition and/or Schiff base reactions, on the other hand, enabled easy bioconjugation of targeting ligands such as DNA aptamer for specific recognition of the nanochains to cancer cells, which led to magnetolysis of the cancer cells in a spinning magnetic field. The PDA-enabled strategy allows for flexible selection of magnetic building blocks and post-synthesis functionalization, which are of considerable interest for a wide spectrum of chemical and biomedical applications.

Versatile Surface Modification Using Polydopamine and Related Polycatecholamines: Chemistry, Structure, and Applications

“…Additional reducing agents have been used in metallization of catecholamine surfaces both to tune morphology or to promote reduction of metal ions with relatively high reduction potentials. Using this technique, composites with silver nanoparticles, gold nanoparticles, and lead nanoparticles have been synthesized for applications as diverse as catalysis, electrochemical and optical sensing, as well as the production of antibacterial surfaces.…”

“…Second, polydopamine coatings on magnetically aligned magnetite nanoparticles created robust, rigid nanochains. These nanochains were then further modified with DNA aptamers for recognition and binding of the nanochains to cancer cells, whereby subsequent employment of a magnetic field resulted in mechanical damage to those cells and cell death . Finally, polydopamine was used to coat poly( d , l ‐lactide‐ co ‐glycolide) to enable subsequent modification by hepatitis B surface antigen and CpG, an immune activating DNA sequence.…”

“…Polycatecholamines have been exploited variously for the treatment of water, including the use in binding of pollutants, as part of composites employed in the catalytic degradation of pollutants and the separation of pollutants through filtration . One key aspect that needs to be considered when pursuing this aspect of polycatecholamine technology is the supramolecular construction of these materials and the potential for their slow degradation under changing aqueous conditions that vary in pH or contain oxidizing agents.…”

“…Polydopamine functionalization has also been used to make catalytic systems suitable for the degradation of organic pollutants for environmental remediation. This includes polydopamine coatings used to bind various metal and metal oxide nanoparticles used to catalyze the degradation of organic pollutants . Examples of these include some interesting photocatalytic systems such as the attachment of titanium dioxide nanoparticles onto filtration membranes for the photocatalytic degradation of the proteins ( Figure ) .…”

Single Metal of Silver Nanoparticles in the Microemulsion for Recyclable Catalysis of 4-Nitrophenol Reduction

“…4-aminophenol (4-AP) is very useful and important in many applications including analgesic and antipyretic drugs, photographic development, corrosion inhibition, anticorrosion lubrication, hair-dyeing agent etc [27]. Therefore enormous current interests have arisen in the development of catalysts for reduction of the 4-NP to 4-AP [28][29][30]. Traditional methods for this process usually involve reduction/catalytic hydrogenation [31][32][33][34][35].…”