Chemical & Biomedical Imaging最新文献

Photoacoustic imaging (PAI), renowned for its high spatial resolution and deep tissue penetration, holds great promise for disease diagnosis and molecular detection. However, the performance of commercially available PAI contrast agent is often hindered by intrinsic fluorescence, which reduces photoacoustic (PA) signal intensity and contrast, thereby limiting their applications. Herein, we rationally designed and synthesized a class of PAI contrast agents based on a phenothiazine core. By precise molecular engineering, we introduced a twisted intramolecular charge transfer (TICT) effect to suppress fluorescence, minimize radiative decay, and facilitate nonradiative energy dissipation, thereby enhancing photothermal conversion efficiency and significantly improving PA signal intensity and imaging contrast-to-noise ratio both in vitro and in vivo. Moreover, the structure facilitates the convenient incorporation of derivatization sites, allowing for further structural expansion and modification. Building upon this platform, we developed a hypochlorous acid (HOCl)-responsive PA probe, DHU-PAOCl-1, to further explore the biomedical imaging potential of these designed contrast agents. DHU-PAOCl-1 exhibited high selectivity and pH stability, with a detection limit of 11.88 nM. In a dermatitis animal model, DHU-PAOCl-1 enabled precise in situ visualization of endogenously generated HOCl at inflammatory sites, offering a powerful imaging tool for the early diagnosis and real-time monitoring of inflammation-related diseases. Collectively, this study provides an effective molecular design strategy for high-performance PAI contrast agents and expands the application potential of PAI technology in molecular diagnostics and therapeutic monitoring.

The excessive utilization of antibiotics escalates the susceptibility to bacterial infections in the general populace. The misuse of antibiotics and the emergence of bacterial resistance can be effectively regulated through the implementation of bacterial detection technology. Therefore, the construction of a multifunctional platform for bacterial detection and removal holds immense significance. In this research, we have effectively developed an imidazolium ionic liquid (TPE-IL) based on the tetraphenylethylene (TPE) structure with aggregation-induced emission (AIE), enabling effective bacterial imaging, biofilm inhibition, and mixed bacterial infection wound healing. TPE-IL effectively targets and penetrates bacterial surfaces via the electrostatic interactions of its imidazole groups and the hydrophobic interactions of its alkyl chains. This dual-action mechanism not only enhances fluorescence emission from the bacterial surface, enabling precise bacterial imaging, but also exhibits significant bactericidal activity. TPE-IL revealed superior antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The in vitro anti-biofilm experiments demonstrated that TPE-IL exhibited remarkable inhibitory effects on biofilms formed by S. aureus and E. coli. The in vivo antibacterial experiments confirmed the potent in vivo bactericidal activity of TPE-IL, which significantly reduced inflammatory responses, enhanced collagen deposition, and promoted wound healing without inducing organ damage in mice. Moreover, TPE-IL displayed low cytotoxicity and hemolysis rate. This work has successfully developed a safe and effective platform for bacterial identification and antimicrobial treatment, thereby offering significant implications in addressing the challenges associated with antibiotic resistance and misuse.

In order to explore the complex interaction between H₂S and the development of related diseases, it is urgently necessary to develop effective visualization methods to monitor the dynamic changes of H₂S in real time. Herein, we constructed the NIR fluorescent probe HCy-SSPy based on disulfide cleavage for the rapid imaging of H₂S. The hemicyanine (HCy-NH₂) unit was used as a NIR fluorophore, and asymmetric pyridyl disulfides (SSPy) acted as the specific recognition receptor for H₂S. The synthesized HCy-SSPy showed a remarkable NIR turn-on signal at 765 nm activated by H₂S. This probe also possessed excellent selectivity and high sensitivity, as well as rapid detection ability for H₂S (∼5 s). Moreover, the low cytotoxicity, mitochondrial localization, and excellent cell imaging performance of HCy-SSPy were discussed. Further biological experiments revealed that the probe not only imaged H₂S in tumor-bearing mice but also showed great potential for H₂S detection in inflammatory processes.

Early disease diagnosis hinges on the sensitive detection of signaling molecules. Among them, hydrogen sulfide (H₂S) plays an important role in cardiovascular and neurological signal transduction. On-chip immunoanalysis, particularly interface detection based on nanoarrays, offers a highly promising avenue for ultrasensitive analysis due to its confined reaction volume and precise signal localization. This study introduces a Ag nanoparticle (NP) array for the sensitive detection of sulfide. The array applies the exceptional sensitivity of Ag to sulfide, where Ag reacts with S^2- to form Ag₂S, leading to a decrease in scattering intensity. The inherent parallel nature of the array with hundreds of independent reactions significantly enhances measurement reliability. The developed Ag nanoarray sensor demonstrates a remarkable response toward hydrogen sulfide across a wide dynamic range spanning 7 orders of magnitude (10 fM to 10 nM). This approach for sulfide detection provides an advanced platform with significantly enhanced sensitivity for biological sensing. Moreover, it holds great potential for the ultrahigh sensitivity detection of a diverse range of other biosignaling molecules.