On-chip human lymph node stromal network for evaluating dendritic cell and T-cell trafficking.

The lymph node paracortex, also known as the T-cell zone, consists of a network of fibroblastic reticular cells (FRCs) that secrete chemokines to induce T-cell and dendritic cell (DC) trafficking into the paracortex. To model the lymph node paracortex, we utilize multi-channel microfluidic devices to engineer a 3D lymph node stromal network from human cultured FRCs embedded in a collagen I-fibrin hydrogel. In the hydrogel, the FRCs self-assemble into an interconnected network, secrete the extracellular matrix proteins entactin, collagen IV, and fibronectin, as well as express an array of immune cell trafficking chemokines.

Progress in developing microphysiological systems for biological product assessment.

Microphysiological systems (MPS), also known as miniaturized physiological environments, have been engineered to create and study functional tissue units capable of replicating organ-level responses in specific contexts. The MPS has the potential to provide insights about the safety, characterization, and effectiveness of medical products that are different and complementary to insights gained from traditional testing systems, which can help facilitate the transition of potential medical products from preclinical phases to clinical trials, and eventually to market. While many MPS are versatile and can be used in various applications, most of the current applications have primarily focused on drug discovery and testing.

Comparison of Engineered Liver 3D Models and the Role of Oxygenation for Patient-Derived Tumor Cells and Immortalized Cell Lines Cocultured with Tumor Stroma in the Detection of Hepatotoxins.

In metabolically active tumors, responses of cells to drugs are heavily influenced by oxygen availability via the surrounding vasculature alongside the extracellular matrix signaling. The objective of this study is to investigate hepatotoxicity by replicating critical features of hepatocellular carcinoma (HCC). This includes replicating 3D structures, metabolic activities, and tumor-specific markers.

Fabrication of oxygen-carrying microparticles functionalized with liver ECM-proteins to improve phenotypic three-dimensional in vitro liver assembly, function, and responses.

Oxygen and extracellular matrix (ECM)-derived biopolymers play vital roles in regulating many cellular functions in both the healthy and diseased liver. This study highlights the significance of synergistically tuning the internal microenvironment of three-dimensional (3D) cell aggregates composed of hepatocyte-like cells from the HepG2 human hepatocellular carcinoma cell line and hepatic stellate cells (HSCs) from the LX-2 cell line to enhance oxygen availability and phenotypic ECM ligand presentation for promoting the native metabolic functions of the human liver. First, fluorinated (PFC) chitosan microparticles (MPs) were generated with a microfluidic chip, then their oxygen transport properties were studied using a custom ruthenium-based oxygen sensing approach.

Generation of Oxygenating Fluorinated Methacrylamide Chitosan Microparticles to Increase Cell Survival and Function in Large Liver Spheroids.

Despite advances in the development of complex culture technologies, the utility, survival, and function of large 3D cell aggregates, or spheroids, are impeded by mass transport limitations. The incorporation of engineered microparticles into these cell aggregates offers a promising approach to increase spheroid integrity through the creation of extracellular spaces to improve mass transport. In this study, we describe the formation of uniform oxygenating fluorinated methacrylamide chitosan (MACF) microparticles via a T-shaped microfluidic device, which when incorporated into spheroids increased extracellular spacing and enhanced oxygen transport via perfluorocarbon substitutions.

Advances in removing mass transport limitations for more physiologically relevant 3D cell constructs.

Spheroids and organoids are promising models for biomedical applications ranging from human disease modeling to drug discovery. A main goal of these 3D cell-based platforms is to recapitulate important physiological parameters of their organ counterparts. One way to achieve improved biomimetic architectures and functions is to culture cells at higher density and larger total numbers.

Fluorinated Chitosan Microgels to Overcome Internal Oxygen Transport Deficiencies in Microtissue Culture Systems.

Poor oxygen transport is a major obstacle currently for 3D microtissue culture platforms, which at this time cannot be grown large enough to be truly physiologically relevant and replicate adult human organ functions. To overcome internal oxygen transport deficiencies, oxygenating microgels are formed utilizing perfluorocarbon (PFC) modified chitosan and a highly scalable water-in-oil miniemulsion method. Microgels that are on the order of a cell diameter (≈10 µm) are formed allowing them to directly associate with cells when included in 3D spheroid culture, while not being internalized.

The Effect of Lucite Glass Reinforcement on the Properties of Conventional Glass-Ionomer Filling Materials.

Statement Of The Problem: The usage of glass ionomer cements (GICs) restorative materials are very limited due to lack of flexural strength and toughness.

Purpose: The aim of this study was to investigate the effect of using a leucite glass on a range of mechanical and optical properties of commercially available conventional glass ionomer cement.

Materials And Method: Ball milled 45μm leucite glass particles were incorporated into commercial conventional GIC, Ketac-Molar Easymix (KMEm).

Effects of three surface conditioning techniques on repair bond strength of nanohybrid and nanofilled composites.

Background: Repair bond strength of different composite resins has been assessed in few studies. In addition, reports on the efficacy of surface treatments are debated. Therefore, this in vitro study was conducted to evaluate the effect of three surface treatments on two nanocomposites versus a microhybrid composite.

Sunflower Seed and Acne Vulgaris.

Background: Regardless of the overall association between diet and acne which cannot be easily ignored, there might be an association between specific nutrients and acne development or improvement.

Objectives: The aim of this study was to assess the effect of dietary intake of sunflower seeds on acne severity and the pattern of acne lesions.

Patients And Methods: In a randomized controlled trial, 50 patients aged 15 - 30 years old with acne vulgaris were enrolled through consecutive convenient sampling, in a dermatology clinic in Ardabil, Iran.