Biomedical-Optical-Window Tailored Cyanines for Steerable Inflammatory Bowel Disease Theranostic

Reengineering Cyanine Dyes via Borondifluoro Indolenine: A Tunable Platform for Wash-Free Imaging and Responsive Biosensing

Fluorescent probes are essential tools for visualizing biological processes, yet conventional cyanine dyes suffer from limited structural flexibility, poor photostability, and weak compatibility with wash-free imaging. Here, we introduce a modular, neutral BF2-bridged cyanine (BCy) platform by re-engineering the indolium scaffold with a borondifluoro indolenine (BFI) fragment. BCy dyes exhibit high brightness (up to 12.4 × 104 M-1 cm-1), robust photostability, and emissions spanning 588-837 nm. The tunable BFI moiety enables the construction of wash-free, far-red/NIR probes for the plasma membrane, lipid droplets, mitochondria, and lysosomes as well as pH- and H2O2-responsive sensors. These probes support high-contrast multicolor and STED imaging, as well as dynamic organelle tracking in live cells and a mouse model of liver injury. This work establishes BF2-cyanines as robust scaffolds for next-generation fluorophores in advanced bioimaging and biomedical diagnostics.

Near-infrared II cyanine fluorophores with large stokes shift engineered by regulating respective absorption and emission

Fluorescence bioimaging in the near-infrared II window is a promising area due to its deep tissue penetration and high contrast. However, efficient design strategies for near-infrared II fluorophores with large Stokes shifts are still scarce. Here, we develop a series of near-infrared II fluorophores (termed VIPIs) with large Stokes shifts (167-260 nm in chloroform) by conjugating p-aminostyryl to hemicyanines. Time dependent density functional theory calculation and transient absorption spectra reveal that the excitation process is predominantly localized within the cyanine moiety, whereas the emission process involves the charge transfer from the cyanine to styryl moiety. We demonstrate the applications of VIPIs in multicolor imaging and conjugatable modification. Finally, we show that VIPI-4 liposomes can image the fine bone structure of knee joint of female mice over 1300 nm. This work provides insights into the excited-state photophysical processes in near-infrared II window, offering inspiration for designing fluorophores with extended emission and large Stokes shifts.

CO-Releasing Polyoxometalates Nanozyme with Gut Mucosal Immunity and Microbiota Homeostasis Remodeling Effects for Restoring Intestinal Barrier Integrity

Disruption of the intestinal epithelial barrier, driven by imbalances in gut mucosal immunity and microbial homeostasis, is central to the onset and progression of inflammatory bowel disease (IBD). This study introduces a CO-releasing polyoxometalates (POMs) nanozyme (PMC), synthesized by coordinating pentacarbonyl manganese bromide with molybdenum-based POM nanoclusters. PMC demonstrates targeted accumulation at IBD-affected sites, efficient scavenging of reactive oxygen species (ROS), and responsive CO release, resulting in multiple therapeutic effects. Extensive in vitro and in vivo studies have validated the exceptional capacity of PMC to repair intestinal barrier, attributed to their potent antioxidant and anti-inflammatory properties, thereby achieving significant therapeutic efficacy in ulcerative colitis treatment. 16S rRNA sequencing indicated that PMC efficiently remodeled the gut microbiota composition. Single-cell RNA sequencing indicates a reduction in pro-inflammatory M1 macrophages, alongside suppressed ROS and inflammatory signaling pathways. Concurrently, an increase in reparative M2 macrophages and intestinal stem cells is observed, in addition to significant activation of the VEGF signaling pathway in macrophages and the NOTCH pathway in stem cells, underscoring the potential of PMC to restore immune balance and promote tissue repair. This study positions PMC as a promising, multifunctional therapeutic agent for IBD treatment owing to its robust intestinal barrier-restoring capability.

Novel Mitochondria-Targeted Asymmetric Heptamethine Cyanine Dye for Cancer Targeted NIR Imaging and Potent Necrosis and Senescence Induction with Prolonged Retention

Developing small molecules that inherently integrate highly tumor-targeted near-infrared fluorescence (NIRF) imaging with potent therapeutic effects remains challenging in anticancer theranostics. Here, we synthesized and characterized a series of heptamethine cyanine PSs with symmetric and asymmetric structures. Among them, we first discovered that asymmetric structures significantly enhanced tumor targeting. Also, a novel mitochondria-targeted asymmetric compound 17 exhibited superior NIRF imaging capability, exceptional tumor selectivity (TNR = 8.54), and strong antitumor activity. Compound 17 selectively accumulates in mitochondria, driven by MMP, where it generates ROS, induces DNA damage, and triggers senescence, apoptosis, and necrosis. Its strong therapeutic efficacy was demonstrated across multiple models, including patient-derived xenograft (PDX), where it allowed precise tumor visualization, significantly suppressed tumor growth with a single administration, and showed no detectable toxicity. Notably, the single-dye small molecule 17 was retained in tumors for over 120 h, enabling prolonged imaging, targeted therapy, and drug delivery for integrated antitumor treatment.