Bacterium‐Templated Polymer for Self‐Selective Ablation of Multidrug‐Resistant Bacteria

The recognition and inactivation of specific pathogenic bacteria remain an enormous scientific challenge and an important therapeutic goal. Therefore, materials that can selectively target and kill specific pathogenic bacteria, without harming beneficial strains are highly desirable. Here, a material platform is reported that exploits bacteria as a template to synthesize polymers with aggregation‐induced emission (AIE) characteristic by copper‐catalyzed atom transfer radical polymerization for self‐selective killing of the bacteria that templates them with no antimicrobial resistance. The bacteria‐templated polymers show very weak fluorescence in aqueous media, however, the fluorescence is turned on upon recognition of the bacteria used as the template to synthesize the polymer even at a low concentration of 600 ng mL^?1. Moreover, the incorporated AIE fluorogens (AIEgens) can act as an efficient photosensitizer for reactive oxygen species (ROS) generation after bacteria surface binding, which endows the templated polymers with the capability for selective bacterial killing. The bacterium‐templated synthesis is generally applicable to a wide range of bacteria, including clinically isolated multidrug‐resistant bacterial strains. It is envisioned that the bacterium‐templated method provides a new strategy for bacteria‐specific diagnostic and therapeutic applications.     

A Dual‐Functional Photosensitizer for Ultraefficient Photodynamic Therapy and Synchronous Anticancer Efficacy Monitoring

A dual‐functional photosensitizer that demonstrates exceptional photodynamic therapy (PDT) efficacy while simultaneously self‐monitoring the therapeutic response in real time is reported here. Possessing an ultrahigh ¹O₂ quantum yield of 98.6% in water, the photosensitizer TPCI can efficiently induce cell death in a series of carcinoma cells (IC₅₀ values less than 300 × 10^?9 m ) upon irradiation with an extremely low fluence (460 nm, 4 mW cm^?2 for 10 min). In addition, TPCI can self‐monitor cell death in real time. It is weakly fluorescent in living cells before irradiation and lights up the nuclei concomitantly with cell death during PDT treatment by binding with chromatin to activate its aggregation‐induced emission, attributed to its strong binding affinity with DNA. In vivo studies using mouse models bearing H22 and B16F10 tumor cells validate the ultraefficient PDT efficacy of TPCI as well as the precise real‐time noninvasive readout of the tumor response from the beginning of cancer treatment. The dual‐functional TPCI serves as an excellent candidate for single‐agent photodynamic theranostics, and this work represents a new paradigm for the development of molecules with multiple intrinsic functions for future self‐reporting medical applications.     

Efficient Red/Near‐Infrared Fluorophores Based on Benzo[1,2‐b:4,5‐b′]dithiophene 1,1,5,5‐Tetraoxide for Targeted Photodynamic Therapy and In Vivo Two‐Photon Fluorescence Bioimaging

Red/near‐infrared dyes are highly demanded for biological applications but most of them are far from satisfactory. In this work, a series of red/near‐infrared fluorophores based on electron‐withdrawing benzo[1,2‐b:4,5‐b′]dithiophene 1,1,5,5‐tetraoxide (BDTO) are synthesized and characterized. They possess both aggregation‐induced emission, and hybridized local and charge‐transfer characteristics. Crystallographic, spectroscopic, electrochemical and computational results reveal that the oxidation of benzo[1,2‐b:4,5‐b′]dithiophene to BDTO can endow the fluorophores with greatly red‐shifted emission, enhanced emission efficiency, reduced energy levels, enlarged two‐photon absorption cross section, and increased reactive oxygen species generation efficiency. The nanoparticles fabricated with a near‐infrared fluorophore TPA‐BDTO show high photostability and biocompatibility with good performance in targeted photodynamic ablation of cancer cells and two‐photon fluorescence imaging of intravital mouse brain vasculature.