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Abstract MotivationCell communication is predominantly governed by secreted proteins, whose diverse secretion patterns often signify underlying physiological irregularities. Understanding these secreted signals at an individual cell level is crucial for gaining insights into regulatory mechanisms involving various molecular agents. To elucidate the array of cell secretion signals, which encompass different types of biomolecular secretion cues from individual immune cells, we introduce the secretion-signal map (S2Map). ResultsS2Map is an online interactive analytical platform designed to explore and interpret distinct cell secretion-signal patterns visually. It incorporates two innovative qualitative metrics, the signal inequality index and the signal coverage index, which are exquisitely sensitive in measuring dissymmetry and diffusion of signals in temporal data. S2Map’s innovation lies in its depiction of signals through time-series analysis with multi-layer visualization. We tested the SII and SCI performance in distinguishing the simulated signal diffusion models. S2Map hosts a repository for the single-cell’s secretion-signal data for exploring cell secretio-types, a new cell phenotyping based on the cell secretion signal pattern. We anticipate that S2Map will be a powerful tool to delve into the complexities of physiological systems, providing insights into the regulation of protein production, such as cytokines at the remarkable resolution of single cells. Availability and implementationThe S2Map server is publicly accessible via https://au-s2map.streamlit.app/. 

Abstract Aggressive cancers, characterized by high metastatic potential and resistance to conventional therapies, present a significant challenge in oncology. Current treatments often fail to effectively target metastasis, recurrence, and the immunosuppressive tumor microenvironment, while causing significant off‐target toxicity. Here, superparamagnetic copper iron oxide nanoparticles (SCIONs) as a multifunctional platform that integrates magnetic hyperthermia therapy, immune modulation, and targeted chemotherapeutic delivery, aiming to provide a more comprehensive cancer treatment is presented. Specifically, SCIONs generate localized hyperthermia under an alternating magnetic field while delivering a copper‐based anticancer agent, resulting in a synergistic anticancer effect. The hyperthermia induced by SCIONs caused ER stress and ROS production, leading to significant tumor cell death, while the copper complex further enhanced oxidative stress, ferroptosis, and apoptosis. Beyond direct cytotoxicity, SCIONs disrupted the tumor microenvironment by inhibiting cancer‐associated fibroblasts, downregulating epithelial‐mesenchymal transition markers, and reducing cell migration and invasion, thereby limiting metastasis. Additionally, SCION‐based therapy reprogrammed the immune microenvironment by inducing immunogenic cell death and enhancing dendritic cell activation, resulting in increased CD8+ T cell infiltration and amplified antitumor immunity. This integrated approach targets primary and metastatic tumors while mitigating immunosuppression, offering a promising next‐generation therapy for combating cancer with enhanced efficacy and reduced side effects. 

The mid‐infrared with a characteristic wavelength of 3–20 μm is important for a wealth of technologies. In particular, mid‐infrared spectroscopy can reveal material composition and structure information by fingerprinting chemical bonds’ infrared resonances. Despite these merits, state‐of‐the‐art mid‐infrared techniques are spatially limited above tens of micrometers due to the fundamental diffraction law. Herein, recent progress in the scanning probe nanoscale infrared characterization of biochemical materials and natural specimens beyond this spatial limitation is reviewed. By leveraging the strong tip–sample local interactions, scanning probe nano‐infrared methods probe nanoscale optical and mechanical responses to disclose material composition, heterogeneity, orientation, fine structure, and phase transitions at unprecedented length scales. These advances, therefore, revolutionize the understanding of a broad range of biochemical and natural materials and offer new material manipulation and engineering opportunities close to the ultimate length scales of fundamental physical, chemical, and biological processes. 

Colorimetric enzyme-linked immunosorbent assay (ELISA) has been widely applied as the gold-standard method for cytokine detection for decades. However, it has become a critical challenge to further improve the detection sensitivity of ELISA, as it is limited by the catalytic activity of enzymes. Herein, we report an enhanced colorimetric ELISA for ultrasensitive detection of interleukin-6 (IL-6, as a model cytokine for demonstration) using Pd@Pt core@shell nanodendrites (Pd@Pt NDs) as peroxidase nanomimics (named “Pd@Pt ND ELISA”), pushing the sensitivity up to femtomolar level. Specifically, the Pd@Pt NDs are rationally engineered by depositing Pt atoms on Pd nanocubes (NCs) to generate rough dendrite-like Pt skins on the Pd surfaces via Volmer–Weber growth mode. They can be produced on a large scale with highly uniform size, shape, composition, and structure. They exhibit significantly enhanced peroxidase-like catalytic activity with catalytic constants (Kcat) more than 2000-fold higher than those of horseradish peroxidase (HRP, an enzyme commonly used in ELISA). Using Pd@Pt NDs as the signal labels, the Pd@Pt ND ELISA presents strong colorimetric signals for the quantitative determination of IL-6 with a wide dynamic range of 0.05–100 pg mL−1 and an ultralow detection limit of 0.044 pg mL−1 (1.7 fM). This detection limit is 21-fold lower than that of conventional HRP-based ELISA. The reproducibility and specificity of the Pd@Pt ND ELISA are excellent. More significantly, the Pd@Pt ND ELISA was validated for analyzing IL-6 in human serum samples with high accuracy and reliability through recovery tests. Our results demonstrate that the colorimetric Pd@Pt ND ELISA is a promising biosensing tool for ultrasensitive determination of cytokines and thus is expected to be applied in a variety of clinical diagnoses and fundamental biomedical studies.