Phototherapy and Mechanism Exploration of Biofilm and Multidrug‐Resistant Helicobacter pylori by Bacteria‐Targeted NIR Photosensitizer

Abstract Helicobacter pylori ( H. pylori ) infection has been the leading cause of gastric cancer development. In recent years, the resistance of H. pylori against antibiotic treatment has been a great challenge for most countries worldwide. Since biofilm formation is one of the reasons for the antibiotic resistance of H. pylori , and phototherapy has emerged as a promisingly alternative antibacterial treatment, herein the bacteria‐targeted near‐infrared (NIR) photosensitizer (T780T‐Gu) by combining positively‐charged guanidinium (Gu) with an efficient phototherapeutic agent T780T is developed. The proposed molecule T780T‐Gu exhibits synergistic photothermal therapy/photodynamic therapy effect against both H. pylori biofilms and multidrug‐resistant (MDR) clinical strains. More importantly, the phototherapy mechanism of T780T‐Gu acquired by the RNA‐seq analysis indicates that structural deficiency as well as a decrease in metabolism and defense activity are the possible reasons for the efficient H. pylori phototherapy.