Catechol-based polyphenols via metal coordination (MPNs)

Catechol-based polyphenols via metal coordination, commonly referred to as metal-phenolic networks (MPNs), represent a class of supramolecular materials formed by the rapid self-assembly of polyphenolic ligands and various metal ions (Ejima et al., 2013). These systems are not biological targets such as receptors or enzymes; instead, they serve as versatile platforms for drug delivery, bioimaging, and surface engineering (Rahim et al., 2016). The coordination between catechol or galloyl groups and metal ions like Fe3+, Al3+, or Zn2+ allows for the formation of thin films or nanoparticles that are inherently pH-responsive, disassembling in acidic environments to facilitate targeted drug release (Guo et al., 2014). Biologically, these assemblies leverage the natural antioxidant, anti-inflammatory, and antimicrobial properties of polyphenols such as tannic acid or epigallocatechin gallate (EGCG) (Wang et al., 2019). They are frequently employed in nanomedicine to encapsulate diverse therapeutic cargo, including small molecules, proteins, and nucleic acids, to improve their stability and bioavailability (Ping et al., 2015). Consequently, they are extensively researched for applications in oncology, wound healing, and the treatment of chronic inflammatory conditions.

Other names

Metal-phenolic networksPolyphenol-metal coordination complexesCatechol-metal assembliesSupramolecular metal-phenolic coatingsMetal-phenolic capsules

These assemblies function as pH-responsive delivery vehicles that remain stable at physiological pH but disassemble in acidic environments (such as the tumor microenvironment or lysosomes) to release encapsulated therapeutic agents. They also exhibit intrinsic therapeutic effects by utilizing the redox activity of phenolic groups to scavenge reactive oxygen species (ROS) and inhibit oxidative damage.