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Herein, protoporphyrin IX (PPIX) was covalently grafted onto a bacterial cellulose (BC) surface via three diamine spacer arms with different chain lengths. The obtained materials were characterized by spectroscopic (infrared, Raman, UV-Vis diffuse reflectance, electron paramagnetic and fluorescence) and physical (elemental, gravimetric) methods. Antibacterial efficacy was evaluated against Staphylococcus aureus and Escherichia coli, and the PPIX supported BC surface exhibited specific antibacterial photodynamic inactivation against E. coli. The 1,2-bis(2-aminoethoxy)ethane aminated BC immobilized the maximal amount of PPIX, and the resulting photosensitive surface achieved a 99.999% (1st cycle) inactivation efficiency against E. coli, but relatively low efficiency against S. aureus. A mechanism of Gram negative bacterial inactivation was proposed as the positively charged PPIX-conjugated BC surface coupled with sufficient 1O2 generation. Though the reusability of the as-fabricated materials needs to be further enhanced, this work provides a potent strategy for efficient photodynamic inactivation against Gram negative bacteria using neutral photosensitizers. [ABSTRACT FROM AUTHOR]