Chemical & Biomedical Imaging最新文献

Image-based single-particle tracking (SPT) provides insight into complex transport within diverse biological and porous material structures, but its performance is constrained by motion blur and a low signal-to-noise ratio (SNR). Traditional SPT methods are sensitive to localization errors and often struggle with short trajectories and fast-moving emitters. In this work, we develop D-Blur, a U-Net-based convolutional neural network (CNN) algorithm designed to localize single particles and predict their diffusion coefficients (D) from motion-blurred point spread functions (PSFs). The obtained D values of emitters enable the reconstruction of diffusion maps on confined transport in porous materials. We validate the algorithm with simulated emitters in a heterogeneous environment, as well as the experimental data of free diffusers in a controlled diffusion environment. By directly extracting molecular dynamics from microscopy images without requiring trajectory linking, D-Blur overcomes key limitations of conventional SPT, providing a solution for subdiffraction diffusion maps within the native imaging flow of fluorescence microscopy. This work enhances diffusion analysis in complex systems and lays the foundation for future applications.

Chemiluminescence imaging, a highly sensitive and noninvasive modality, has emerged as an invaluable tool for bioimaging by virtue of its high signal-to-noise ratio and minimal background interference. The absence of an external excitation source enables chemiluminescent probes to directly convert chemical energy into light via oxidation reactions, yielding highly specific and quantifiable signals. Recent advances in small molecule-based chemiluminescent probes have opened further avenues for monitoring dynamic biological processes and pathological events in vivo, particularly those related to reactive oxygen and nitrogen species (RONS). These molecular probes are engineered to detect key RONS, such as singlet oxygen (¹O₂), hydrogen peroxide (H₂O₂), superoxide anions, peroxynitrite (ONOO^-), superoxide anions (O₂ ^•-), and hypochlorite (ClO^-), that play critical roles in oxidative stress, inflammation, cancer, and neurodegeneration. Their ability to offer real-time, quantitative insights into the presence and kinetics of RONS has significant implications for early disease diagnosis and targeted therapy. This review comprehensively summarizes the latest progress in the development of advanced chemiluminescent probes with simpler, more synthetically accessible, and modifiable structures that exhibit enhanced biocompatibility and broad application potential, while also discussing future challenges and opportunities in this rapidly evolving field.

The development of tracers targeting prostate-specific membrane antigen (PSMA) has great significance for improving the diagnosis and treatment of prostate cancer (PCa). In this study, a dimeric PSMA-targeting ligand, PSMA-DIM, has been designed and synthesized based on the structure of the Glu-urea-Lys pharmacophore by introducing 4-(p-iodophenyl) butyric acid and PEG₄ motifs. [ ⁶⁸ Ga]-Ga-PSMA-DIM exhibited high radiochemical purity (>98%) and stability, with a K _d value for LNCaP cells of 37.09 ± 13.53 nM. The uptake and internalization of [ ⁶⁸ Ga]-Ga-PSMA-DIM by LNCaP cells were significantly higher compared to 22Rv1 or PC-3 cells. The elimination half-life of [ ⁶⁸ Ga]-Ga-PSMA-DIM from the plasma was calculated to be 99.55 min, indicating a significant extension of retention time in vivo. The peak tumor uptake of [ ⁶⁸ Ga]-Ga-PSMA-DIM in LNCaP and 22Rv1 tumor-bearing mice was 4.19 ± 0.65 %ID/mL and 4.08 ± 0.47 %ID/mL, respectively, which was significantly higher than that observed in the PC-3 tumor-bearing mice (2.71 ± 0.70 %ID/mL). Moreover, [ ⁶⁸ Ga]-Ga-PSMA-DIM maintained relatively high uptake in LNCaP and 22Rv1 tumors even after 3 h (3.84 ± 0.50 %ID/mL and 3.59 ± 0.57 %ID/mL, respectively). In conclusion, [ ⁶⁸ Ga]-Ga-PSMA-DIM could sensitively and specifically differentiate models with varying PSMA expression levels and show notable retention in vivo.

Liver fibrosis, a progressive condition marked by excessive extracellular matrix deposition and activation of hepatic stellate cells, often develops asymptomatically in its early stages, leading to delayed clinical intervention. Conventional imaging techniques typically fail to detect mild fibrosis, resulting in diagnosis only at advanced stages such as cirrhosis, when therapeutic efficacy is significantly compromised. Recent advances in molecular imaging have facilitated the development of targeted contrast agents that enhance diagnostic sensitivity by selectively binding to fibrosis-specific biomarkers or responding to pathological microenvironmental changes. These include both nonresponsive probes that accumulate in fibrotic tissue and activatable probes sensitive to enzymes, small molecules, and other fibrosis-associated signals. This review systematically summarizes these emerging strategies and evaluates their potential for improving early diagnosis, staging accuracy, and therapeutic monitoring, thereby guiding future development and applications in hepatic fibrosis management.