Circadian rhythms, essential for regulating human physiology and behavior, are influenced by light exposure, particularly at night. This study examined the impact of red (631 nm) and blue (464 nm) LED light on melatonin secretion, a key circadian marker. Twelve participants aged 19–55 years were exposed to red and blue light for three hours (9:00 p.m.–midnight), with hourly saliva samples analyzed via ELISA to track melatonin levels. Initially, melatonin levels were comparable under both light conditions. After one hour, both lights suppressed melatonin, but differences emerged after two hours: blue light-maintained suppression, with levels at 7.5 pg/mL, while red light allowed recovery to 26.0 pg/mL (p = 0.019). This pattern persisted at the third hour. Blue light had stronger suppression effects, particularly in younger participants and men. These results underscore blue light’s disruptive effects on circadian health and highlight red light as a less disruptive alternative for nighttime environments.

Liver resections are a significant source of primary human hepatocytes used mainly in artificial liver devices and pharmacological and biomedical studies. However, it is not well known how patient-donor and surgery-dependent factors influence isolated hepatocytes’ yield, viability, and function. Hence, we aimed to analyze the impact of all these elements on the outcome of human hepatocyte isolation.Patients and methods: Hepatocytes were isolated from liver tissue from patients undergoing partial hepatectomy using a two-step collagenase method. Hepatocyte viability, cell yield, adhesion, and functionality were measured. In addition, clinical and analytical patient variables were collected and the use or absence of vascular clamping and its type (continuous or intermittent) plus the ischemia times during surgery.Results: Malignant disease, previous chemotherapy, and male gender were associated with lower hepatocyte viability and isolation cell yields. The previous increase in transaminases was also associated with lower yields on isolation and lower albumin production. Furthermore, ischemia secondary to vascular clamping during surgery was inversely correlated with the isolated hepatocyte viability. An ischemia time higher than 15 min was related to adverse effects on viability.Conclusion: Several factors correlated with the patient and the surgery directly influence the success of human hepatocyte isolation from patients undergoing liver resection.

Metastasis, the leading cause of cancer-related mortality, is a complex process involving tumor cell detachment from the primary site, survival and dissemination through the circulation, and colonization of distant organs. At each stage, tumor cells face adaptive pressures from successive biological and biomechanical challenges in the local microenvironment, which collectively shape their progression. Traditional in vitro models often fail to replicate these dynamics, while animal models are limited by species differences and restricted real-time monitoring. Microphysiological systems (MPS) have emerged as powerful tools to address these limitations, delivering physiologically relevant cues and precise experimental control to recapitulate step-specific metastatic contexts. This review outlines recent advances in MPS designs for modeling critical hallmarks of metastasis, beginning with matrix interactions, stromal cells, and mechanical forces from the tumor microenvironment that drive epithelial-mesenchymal transition and invasion. The discussion then transitions to MPS that reproduce vascular physiology during intravasation, circulation, and extravasation, and concludes with organ-specific environments for studying colonization and organotropic behavior in the final stages of metastasis. Additionally, common MPS configurations, categorized into horizontal and vertical compartmental arrangements, and strategies for integrating vascularization are explored. Together, these advances highlight the potential of MPS in elucidating metastatic mechanisms and advancing targeted therapies.

Metastatic dissemination is the leading cause of cancer‐related mortality, yet the early steps in this process remain difficult to study using current experimental models. Although organ‐on‐a‐chip platforms recapitulate key features of the tumor microenvironment (TME), most fail to integrate physiologically relevant invasion, intravasation, and circulation within a single system. Membrane‐ and pillar‐based designs hinder endothelial crossing and imaging, while open‐interface approaches often lack stable perfusion and controlled positioning of 3D cell aggregates. Here, an open‐port, barrier‐free microfluidic device is presented, fabricated via surface treatment‐based patterning, for investigating early metastatic progression from a tumor spheroid. The planar device incorporates a centrally confined gel matrix accessible via a top‐loading port for precise spheroid placement, flanked by endothelialized lateral channels in direct contact with the matrix and perfusable under defined shear stress. Using MDA‐MB‐231 breast cancer spheroids, the model recapitulates key aspects of tumor cell migration, tumor‐induced endothelial disruption, and intravasation, while enabling flow‐mediated downstream recovery of viable intravasated cells. Overall, this device provides a physiologically relevant platform for the integrated, high‐resolution, and longitudinal investigation of early metastatic events, providing a foundation for future mechanistic studies and molecular characterization of metastatic cell populations.

Current skin microbiota models are limited in their ability to mimic the complexity of healthy human skin. Here, we developed a physiologically relevant full-thickness skin-on-chip model integrating commensal microbiota and artificial sweat, providing a novel platform to study microbiota dynamics and skin barrier function.