Polyphenol-Functionalized Plant Viral-Derived Nanoparticles Exhibit Strong Antimicrobial and Antibiofilm Formation Activities

(-)-Epigallocatechin gallate (EGCG) is a polyphenolic compound that shows a number of health-promoting effects, especially a broad antimicrobial activity. Virus-derived nanoparticles (VNPs) represent a promising drug carrier since they possess properties like biodegradability and their surface and interior are highly modifiable. Turnip mosaic virus (TuMV) VNPs offer an attractive number of conjugation sites on the external surface. EGCG-TuMV VNPs were synthesized by Mannich condensation, and their antimicrobial activities against the model bacteria Sarcina lutea, Pseudomonas aeruginosa, and Dickeya dadantii were tested. EGCG-TuMV VNPs did not only maintain TuMV structure but also showed an enhanced antimicrobial activity over that found with free EGCG for all of the bacteria tested. Biofilm formation by P. aeruginosa was also inhibited by EGCG-TuMV VNPs, contrary to free EGCG, which induced higher amounts of biofilm mass in a concentration-dependent manner. Taken together, our results open highly promising perspectives for the antimicrobial exploitation of EGCG-TuMV VNPs.