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Abstract: 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. [ABSTRACT FROM AUTHOR]

A novel theranostic divalent vancomycin analog using a planar 1,8-diazapyrene moiety as a rigid scaffold exhibits potent and selective antibacterial activity against Gram (+) bacteria including vancomycin-resistant strains, while having minimal influence on Gram (−) bacteria and mammalian cells. Moreover, this theranostic analog can be also applied for selective two-photon fluorescence imaging of Gram (+) bacteria. [ABSTRACT FROM AUTHOR]

A polymer and silica co-protection strategy has been developed to encapsulate organic fluorogens with aggregation-induced emission and charge transfer characteristics into small nanoparticles (NPs). The co-pretected NPs show bright red fluorescence (50% quantum yield) with a large two-photon action cross-section (450 GM at 840 nm), which have been sucessfully used for two-photon fluorescence imaging of vasculature of the mouse tibial muscle. [ABSTRACT FROM AUTHOR]

BODIPY (4,4-difluoro-4-bora-3a,4a-diaza- s-indacene) is an emissive chromophore in solutions but suffers from fluorescence quenching when aggregated due to its flat molecular conformation and small Stokes shift. To create aggregate-state emissive BODIPY luminogens, tetraphenylethene (TPE), which is a popular luminogen with intriguing aggregation-induced emission (AIE) characteristic, is introduced as periphery to a methylated BODIPY core. Three TPE-BODIPY adducts are synthesized and characterized, and their photophysical properties and electronic structures are investigated. The incorporation of AIE-active TPE units alleviates aggregation-caused quenching of BODIPY core, furnishing emissive nanoparticles based on TPE-BODIPY adducts. Significantly, the two-photon absorption (TPA) and two-photon excited fluorescence (TPEF) properties are improved as more TPE units are attached. The luminogens with 3TPE units (3TPE-BODIPY) shows the strongest TPA and TPEF in the wavelength range of 750-830 nm, with cross-section values of 264 and 116 GM at 810 nm, respectively. Red emissive nanoparticles with a Stokes shift of 60 nm and a fluorescence quantum yield of 16% are attained by encapsulating 3TPE-BODIPY with 1,2-sistearoyl- sn-glycero-3-phosphoethanolamine- N-[methoxy(polyethylene glycol)-2000]. The nanoparticles are biocompatible and function well in TPEF cellular imaging and mouse brain blood vascular visualization. [ABSTRACT FROM AUTHOR]