A self-calibrating flexible SERS substrate incorporating PB@Au assemblies for reliable and reproducible detection.

The precise quantitative analysis using surface-enhanced Raman spectroscopy (SERS) in an uncontrollable environment still faces a significant obstacle due to the poor reproducibility of Raman signals. Herein, we propose a facile method to fabricate a self-calibrating substrate based on a flexible polyvinyl alcohol (PVA) film comprising assemblies of Prussian blue (PB) and Au NPs (PB@Au) for reliable detection. PB cores were coated with an Au shell through simple electrostatic interaction, forming core-shell nanostructure PB@Au assemblies within the PVA film. The outer Au layer provided identical trends in enhancement for both the PB core and neighboring targets while PB cores served as an internal standard (IS) to correct signal fluctuations. The prevention of competitive adsorption on the metal surface between targets and ISs was achieved. The proposed PVA/PB@Au film exhibited enhanced stability of Raman signals after IS correction, resulting in improved spot-to-spot and batch-to-batch reproducibility with significantly reduced standard deviation (RSD) values from 11.42% and 25.02% to 4.43% and 9.39%, respectively. Simultaneously, a higher accuracy in the quantitative analysis of 4-mercaptobenzoic acid (4-MBA) and malachite green (MG) was achieved with fitting coefficient (R2) values improving from 0.9675 and 0.9418 to 0.9974 and 0.9832, respectively. Moreover, the PVA/PB@Au film was successfully applied to detect residual MG in real fish samples. This work opens up an avenue to improve the reproducibility of Raman signals for flexible SERS substrates in the detection of residues under various complex conditions.

Stable inhibition of choroidal neovascularization by adeno-associated virus 2/8-vectored bispecific molecules.

Neovascular age-related macular degeneration (nAMD) causes severe visual impairment. Pigment epithelium-derived factor (PEDF), soluble CD59 (sCD59), and soluble fms-like tyrosine kinase-1 (sFLT-1) are potential therapeutic agents for nAMD, which target angiogenesis and the complement system. Using the AAV2/8 vector, two bi-target gene therapy agents, AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59, were generated, and their therapeutic efficacy was investigated in laser-induced choroidal neovascularization (CNV) and Vldlr-/- mouse models. After a single injection, AAV2/8-mediated gene expression was maintained at high levels in the retina for two months. Both AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 significantly reduced CNV development for an extended period without side effects and provided efficacy similar to two injections of current anti-vascular endothelial growth factor monotherapy. Mechanistically, these agents suppressed the extracellular signal-regulated kinase and nuclear factor-κB pathways, resulting in anti-angiogenic activity. This study demonstrated the safety and long-lasting effects of AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 in CNV treatment, providing a promising therapeutic strategy for nAMD.

Sensitive SERS assay for L-cysteine based on functionalized silver nanoparticles.

L-cysteine, an indispensable amino acid present in natural proteins, plays pivotal roles in various biological processes. Consequently, precise and selective monitoring of its concentrations is imperative. Herein, we propose a Surface-enhanced Raman Scattering (SERS) sensor for detecting L-cysteine based on the anti-aggregation of 4-mercaptobenzoic acid (4-MBA) and histidine (His) functionalized silver nanoparticles (Ag NPs). The presence of Hg2+ ions can induce the aggregation of Ag NPs@His@4-MBA due to the unique nanostructures of Ag NPs@His@4-MBA, resulting in a robust SERS intensity of 4-MBA. However, in the presence of L-cysteine, the stronger affinity between L-cysteine and Hg2+ reduces the concentration of free Hg2+, causing the dispersion of the aggregated functionalized Ag NPs and the reduction of the SERS signal intensity of 4-MBA. The developed SERS platform demonstrates excellent performance with a low detection limit of 5 nM (S/N = 3) and linear detection capabilities within the range of 0.01-100 µM for L-cysteine. Additionally, the method was successfully employed for the determination of L-cysteine in spiked serum samples, yielding recoveries ranging from 95.0 % to 108.1 % with relative standard deviations of less than 3.3 %. This study not only presents a novel approach for fabricating highly sensitive and specific SERS biosensors for biomolecule detection but also offers a significant strategy for the development and construction of SERS substrates using anti-aggregation design.

Exercise alleviates neovascular age-related macular degeneration by inhibiting AIM2 inflammasome in myeloid cells.

The neovascular form of age-related macular degeneration (nvAMD) is the leading cause of blindness in the elderly population. Vascular endothelial growth factor (VEGF) plays a crucial role in choroidal neovascularization (CNV), and anti-VEGF therapy is recommended as first-line therapy for nvAMD. However, many patients do not radically benefit from this therapy. Epidemiological data suggest that physical exercise is beneficial for many human diseases, including nvAMD. Yet, its protective mechanism and therapeutic potential remain unknown. Here, using clinical samples and mouse models, we found that exercise reduced CNV and enhanced anti-angiogenic therapy efficacy by inhibiting AIM2 inflammasome activation. Furthermore, transfusion of serum from exercised mice transferred the protective effects to sedentary mice. Proteomic data revealed that exercise promoted the release of adiponectin, an anti-inflammatory adipokine from adipose tissue into the circulation, which reduced ROS-mediated DNA damage and suppressed AIM2 inflammasome activation in myeloid cells of CNV eyes through AMPK-p47phox pathway. Simultaneous targeting AIM2 inflammasome product IL-1ß and VEGF produced a synergistic effect for treating choroidal neovascularization. Collectively, this study highlights the therapeutic potential of an exercise-AMD axis and uncovers the AIM2 inflammasome and its product IL-1ß as potential targets for treating nvAMD patients and enhancing the efficacy of anti-VEGF monotherapy.