Several subsets of mononuclear phagocytes and DCs (MDC) populate the small intestine (SI), and these cells reportedly exert specialized functions in anti‐microbial immunity and tolerance. Given the specialized phenotype of these cells, differing from other MDC family members, including their putative circulating blood precursors, local intestinal factors play key instructive roles in their differentiation. We designed an SI cell culture model composed of three intestinal epithelial cell (IEC) types, including absorptive enterocytes (E cells), antigen delivering microfold (M) cells, and mucus‐producing goblet (G) cells plus T lymphocytes and soluble B cell‐derived factors. This model was used to study the differentiation fate of CD34⁺ hematopoietic progenitor cell‐derived monocyte/DC precursors. Progeny cells can be analyzed after a 3‐week co‐culture period, mimicking the physiologic turn‐over time of intestinal MDC. A dominant monocyte differentiation pathway was suppressed, in favor of partial differentiation along DC and macrophage pathways, with low percentages of cells acquired DC or macrophage markers. Moreover, E and G cells play opposing roles in CX3CR1⁺ vs CD103^dim cell differentiation, indicating that both together might counter‐balance M/DC differentiation. Thus, SI epithelial cells suppress M/DC differentiation, supporting a key role for exogenous factors in M/DC differentiation.

Retinoic acid (RA) plays a key role in mucosal immune regulation and tolerance, with implications for inflammatory bowel disease (IBD). However, its effects have not been extensively studied in humanized in vitro models that recapitulate epithelial–immune interactions. We established a 3D in vitro small intestinal model composed of three epithelial cell types, naïve CD4⁺ T cells, and monocyte/dendritic cell (M/DC) precursors derived from CD34⁺ umbilical cord blood hematopoietic stem/progenitor cells. The epithelial microenvironment strongly suppressed monocyte/DC differentiation and T cell activation, indicating a regulatory role of epithelial-derived signals. Retinoic acid (RA) priming of M/DC precursors induced CD103⁺CD11b⁺Sirp1α⁻ regulatory DCs and promoted a shift from naive to memory-type T cells. Upon addition of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β), the model mimicked an inflamed intestinal state, resulting in CD14⁺CD16⁺ inflammatory monocytes and increased T cell activation (CD25⁺CD69⁺). RA-primed DCs modestly counterbalanced T cell activation and IBD-like responses, even under inflammatory conditions. Flow cytometry and clustering analysis revealed distinct immune cell phenotypes depending on RA exposure and cytokine context. This model provides a reproducible and physiologically relevant human system to study RA-mediated immune programming in the intestinal mucosa and may support the development of novel therapeutic strategies for IBD and related inflammatory conditions. Statistical differences were evaluated using ANOVA with Tukey’s post-hoc test (n = 4; p < 0.05).

Organic photovoltaics show great potential for wireless bioelectronics, offering the ability to convert visible‐to‐near‐infrared light into electrical energy. This study investigates the stability and biocompatibility of PM6:Y6 bulk heterojunction layers, chosen for their efficient charge separation and absorption profile compatible with the optical transparency of skin tissue, under simulated physiological conditions. Biocompatibility is validated using the chicken chorioallantoic membrane and cytotoxicity assays with primary neurons, showing no adverse effects on cell viability or morphology. The layers demonstrated stable photoinduced charge separation over 28 days in electrolytic environments with a significant voltage increase of ≈40 mV after one day. The addition of a PM6 overlayer improved voltage responses and reduced swelling, possibly acting as a selective barrier, however, leading to a decrease in the achievable peak current densities over time. Atomic force microscopy and transient absorption spectroscopy confirmed the structural and functional stability of the films, with almost unaffected charge generation and recombination rates in aqueous environments. The PM6 layer slowed charge formation due to increased diffusion lengths. These findings underscore the PM6:Y6 blend‘s potential for use in bioelectronics. Future studies should examine PM6:Y6 performance in in vivo conditions and focus on an improved understanding of interaction mechanisms with biological systems.

Carotenoids are plant‐derived bioactive compounds with antioxidant properties and well‐established roles in human health. Circulating carotenoid concentrations are widely used as an objective biomarker of fruit and vegetable intake; however, their assessment by high‐performance liquid chromatography (HPLC) requires invasive sampling and laboratory infrastructure. Reflection spectroscopy–based devices, such as the Veggie Meter and Biozoom, offer rapid, noninvasive alternatives for assessing cutaneous carotenoids (CC), but their validity across different body composition profiles remains insufficiently characterized. In this study, plasma carotenoid concentrations quantified by HPLC were compared with CC measurements obtained using the Veggie Meter and Biozoom in 54 healthy women across three study visits ( n = 151 observations). Associations between plasma and cutaneous carotenoids were evaluated using Spearman and partial correlation analyses with adjustment for body fat percentage and were further examined using linear mixed‐effects models (LMMs) accounting for repeated measurements including body fat percentage and smoking status as covariates. Total plasma carotenoid concentrations were strongly correlated with CC values measured by Biozoom ( r _s (151) = 0.697, p < 0.001) and Veggie Meter ( r _s (151) = 0.650, p < 0.001). Provitamin A carotenoids exhibited the strongest associations, whereas lutein and lycopene showed weaker correlations. All associations remained statistically significant after adjusting for body fat percentage and smoking status. Both plasma and cutaneous carotenoid levels were inversely associated with BMI and obesity‐related measures (all p < 0.0033, after Bonferroni correction for multiple comparisons). These findings support the use of reflection spectroscopy–based cutaneous carotenoid measurements as valid, noninvasive nutritional biomarkers of fruit and vegetable–derived carotenoid exposure. Such tools may facilitate dietary assessment and monitoring in nutrition research, clinical practice, and public health settings, provided that body composition is considered when interpreting results.

Hydrogel-based scaffolds are central to three-dimensional (3D) epithelial culture systems, yet commonly used matrices such as Matrigel^® suffer from batch variability, undefined composition, and limited translational relevance. Here, we comparatively evaluated an animal-free nanocellulose hydrogel (GrowDex^®) and Matrigel^® in a hybrid vascularized intestinal–chorioallantoic membrane (CAM) model. Pre-cultured epithelial–immune constructs (Caco-2/HT29-MTX with immune components) were embedded in both matrices and grafted onto the CAM for 72 h. Histological and immunohistochemical analyses revealed that nanocellulose-based constructs maintained more cohesive epithelial coverage, improved scaffold integrity, and yielded a more continuous cytokeratin-positive layer at the scaffold–CAM interface. In contrast, Matrigel^® constructs frequently exhibited heterogeneous epithelial distribution and central discontinuities. While both matrices enabled CAM engraftment, the chemically defined nanocellulose hydrogel demonstrated enhanced structural robustness during in vivo exposure and histological processing. These findings highlight the suitability of standardized nanocellulose hydrogels for reproducible scaffold-based epithelial models in vascularized environments.