Size engineering of 2D MOF nanosheets for enhanced photodynamic antimicrobial therapy

Although porphyrin-based metal-organic frameworks(MOFs)have been widely explored as photosensi-tizers for photodynamic therapy,how the size will affect the light-induced catalytic activity for generation of reactive oxygen species(ROS)still remain unclear.Herein,we first report the size-controlled synthesis of two-dimensional(2D)porphyrin-based PCN-134 MOF nanosheets by a two-step solvothermal method to explore the size effect on its PDT performance,thus yielding enhanced photodynamic antimicrobial therapy.By simply controlling the reaction temperature in the synthesis process,the bulk PCN-134 crys-tal,large PCN-134(L-PCN-134)nanosheets with a lateral size of 2-3 pm and thickness of 33.2-37.5 nm and small PCN-134 nanosheets(S-PCN-134)with a lateral size of 160-180 nm and thickness of 9.1-9.7 nm were successfully prepared.Interestingly,the S-PCN-134 nanosheets exhibit much higher photodynamic activity for ROS generation than that of the bulk 3D PCN-134 crystal and L-PCN-134 nanosheets under a 660 nm laser irradiation,suggesting that the photodynamic activity of PCN-134 MOF increases when the size reduces.Therefore,the S-PCN-134 nanosheets show much enhanced performance when used as a photosensitizer for photodynamic antimicrobial activity and wound healing.