Self-Assembly of Nano- to Macroscopic Metal–Phenolic Materials

Abstract

The self-assembly of molecular building blocks into well-defined macroscopic materials is desirable for developing emergent functional materials. However, the selfassembly of molecules into macroscopic materials remains challenging, in part because of limitations in controlling the growth and robustness of the materials. Herein, we report the molecular self-assembly of nano-to macroscopic free-standing materials through the coordination of metals with natural phenolic molecules. Our method involves a simple and scalable solution-based template dipping process in precomplexed metal−phenolic solutions, enabling the fabrication of free-standing macroscopic materials of customized architectures (2D and 3D geometries), thickness (about 10 nm to 5 μm), and chemical composition (different metals and phenolic ligands). Our macroscopic free-standing materials can be physically folded and unfolded like origami, yet are selectively degradable. Furthermore, metal nanoparticles can be grown in the macroscopic free-standing films, indicating their potential for future applications in biotechnology and catalysis.

The Biomolecular Corona in 2D and Reverse: Patterning Metal–Phenolic Networks on Proteins, Lipids, Nucleic Acids, Polysaccharides, and Fingerprints

“…An MPN growth time of ≈24 h was necessary for direct visualization of the biomolecule patterns by eye. However, by reducing silver nanoparticles (AgNPs) onto the MPNs in situ, similar to our previous reports on AgNP synthesis on MPNs, patterns were visualized after an MPN growth time of only 1 h because of the enhanced reflectance and fluorescence properties owing to the AgNPs in the films. The preferential growth of the MPNs on the biomolecules over the planar substrate also allowed for the visualization of natural biomolecule patterns, including clean fingerprints invisible to the naked eye (latent and uncharged) or fingerprints deposited after gently rubbing the face (charged) with a resolution down to single sweat pores (the gold standard for forensic profiling) .…”

A Mussel‐Inspired Persistent ROS‐Scavenging, Electroactive, and Osteoinductive Scaffold Based on Electrochemical‐Driven In Situ Nanoassembly

“…Therefore, negatively charged ions, such as PDA and PO 4 3− , can be doped into PPy chains though electrostatic attraction. Furthermore, these PPy‐PDA NPs assembled to form a PPy‐PDA layer (Figure S1, Supporting Information) in situ, which has the ability to absorb Ca 2+ . Similarly, during the second pulse (−1.5 V), HA NPs formed in situ on the Ca 2+ ‐absorbed and PO 4 3− ‐doped PPy‐PDA layer with the assistance of hydroxyl ions via hydrolysis.…”

“…Furthermore, these PPy-PDA NPs assembled to form a PPy-PDA layer (Figure S1, Supporting Information) in situ, which has the ability to absorb Ca 2+ . [25] Similarly, during the second pulse (−1.5 V), HA NPs formed in situ on the Ca 2+ -absorbed and PO 4 3− -doped PPy-PDA layer with the assistance of hydroxyl ions via hydrolysis. Repeating two pulses for several cycles yields a PPy-PDA-HA film.…”

Oxidation‐Mediated Kinetic Strategies for Engineering Metal–Phenolic Networks

“…With this understanding of the film growth process,w e next attempted to control the thickness and microstructure of the MPN films,b oth of which are known to influence the performance of MPN-coated materials.T od ate,s everal methods have been reported for the continuous growth of MPN films,i ncluding rust-mediated assembly,o xygen oxidation assembly,d iffusion-driven assembly,a nd electro-triggered assembly. [7,11,18] These methods are more time-consuming or require specific substrates (e.g., conductive) to obtain thick (> 30 nm) MPN films;h owever, there is still an eed to speed up the growth for thick MPN films.H erein, we demonstrate that the formation of MPN films can be accelerated in the presence of ROSg enerated by ultrasonication (Figure 3a). This method is independent of the substrate properties yet allows for the generation of thick MPN films.T he ROS are more active than molecular oxygen and can accelerate the oxidation rate of TA-Fe II to TA-Fe III .…”