Engineering polyphenol-based polymeric nanoparticles for drug delivery and bioimaging

Polyphenols are compounds with phenolic hydroxyl groups that are widely found in natural plants. The beneficial effects of polyphenols have been studied extensively, especially anti-tumor, anti-inflammatory and anti-bacterial capacity. Therefore, polyphenol-based polymeric nanoparticles emerged in biomedical engineering, especially as carriers for drug delivery. In this review, we provide a brief overview of the components used for engineering, including natural polyphenols, artificial polyphenols and other macromolecules complexed with polyphenols. And the approaches used to engineer polyphenol-based polymeric nanoparticles according to the diverse interactions between polyphenols and other molecules were also discussed in detail. A variety of drugs, such as small molecule drugs, protein drugs and nucleic acids are loaded in polyphenol nanoparticles according to their drug structures and properties for the treatment of various diseases. Moreover, even polyphenol nanoparticles without payload have achieved promising therapeutic effects on inflammation-related diseases. In addition, by loading metal ions such as Fe, Gd and Zr as well as fluorescent dyes, polymeric polyphenol nanoparticles can be used for bioimaging applications including positron emission tomography, single-photon emission computed-tomography, magnetic resonance, near-infrared fluorescence and photoacoustic imaging. The merits and challenges of this nanomedicine in clinical translation were also discussed that need to be considered for further development of this polyphenol-based nanomedicine.