Tannic acid-based metal-phenolic networks as a versatile platform to mediate cell therapy

Surface modification using biomaterials is crucial for constructing bioactive interfaces that can control cell behavior, regulate biological processes, and interact with specific biomolecules. Tannic acid (TA), a naturally derived polyphenol, is of particular interest due to its ability to complex ions, facilitating the fabrication of coordination networks through self-assembly of TA and metal ions, known as metal-phenolic networks (MPNs). These MPNs can form stable, yet dynamic structures that can be further engineered or tailored for specific therapeutic needs. Synthetic TA-based MPN complexes have been constructed to modify diverse biointerfaces due to their unique physiochemical properties, including universal adhesion, pH responsiveness, controllable size and stiffness, ease of preparation, and excellent biocompatibility, which are highly advantageous for various biological applications, particularly in cell therapy. This review explores the synthesis, properties, and applications of TA-based MPNs in the context of therapeutic cells, including bacteria, yeast, and mammalian cells. Key aspects such as biocompatibility, biodegradability, the ability to modulate cellular environments, and clinical translation are discussed, highlighting the potential of TA-based MPNs to advance cell therapy.