Phthalocyanine-Porphyrin Uniform Orthogonal Conjugated Oligomer for NIR Photothermal-Photodynamic Synergistic Antibacterial Treatment

Abstract With the increase of antibiotic resistance worldwide, there is an urgent demand to develop new antibacterial agent and approaches to address the threat to human health posed by the ineffectiveness of traditional antibiotics. In this work, an orthogonal conjugated uniform oligomer bactericide of SiPc-ddCPP was constructed between silicon phthalocyanine and porphyrin via amide bond, which can effectively treat infection through photodynamic-photothermal combined therapy without considering drug resistance. Compared with organic photothermal agents induced by unstable H-aggregation with blue-shifted absorption and fluorescence/ROS quenching, this orthogonal-structured uniform SiPc-ddCPP nanoparticle shows remarkably stability and NIR photothermal effect (η = 31.15%) along with fluorescence and ROS generation, due to the photoinduced intramolecular energy transfer within SiPc-ddCPP. Antibacterial studies have shown that both Gram-positive and Gram-negative bacteria could be efficiently annihilated in a few minutes through synergistic PDT-PTT of SiPc-ddCPP along with satisfactory bacterial targeting. These results suggest SiPc-ddCPP is a multifunctional NIR bactericide, which afford a new approach of PDT-PTT targeted anti-inflammation to conquer the crisis of antibiotic resistance.