Microchannel Molding Combined with Layer-by-Layer Approach for the Formation of Three-Dimensional Tube-like Structures by Endothelial Cells

Advancing Organ-on-a-Chip Systems: The Role of Scaffold Materials and Coatings in Engineering Cell Microenvironment

For organ-on-a-chip (OoC) engineering, the use of biocompatible coatings and materials is not only recommended but essential. Extracellular matrix (ECM) components are commonly used as coatings due to their effects on cell orientation, protein expression, differentiation, and adhesion. Among the most frequently used coatings are collagen, fibronectin, and Matrigel, according to the specific cell type and intended OoC application. Additionally, materials such as polydimethylsiloxane (PDMS), thermoplastics, chitosan, and alginate serve as scaffolding components due to their biomechanical properties and biocompatibility. Here, we discuss some of the most employed coating techniques, including SAMs, dip coating, spin coating, microcontact printing, and 3D bioprinting, each offering advantages and drawbacks. Current challenges comprise enhancing biocompatibility, exploring novel materials, and improving scalability and reproducibility.

Uteroplacental microvascular remodeling in health and disease

The microvascular system is essential for delivering oxygen and nutrients to tissues while removing metabolic waste. During pregnancy, the uteroplacental microvascular system undergoes extensive remodeling to meet the increased demands of the fetus. Key adaptations include vessel dilation and increases in vascular volume, density, and permeability, all of which ensure adequate placental perfusion while maintaining stable maternal blood pressure. Structural and functional abnormalities in the uteroplacental microvasculature are associated with various gestational complications, posing both immediate and long-term risks to the health of both mother and infant. In this review, we describe the changes in uteroplacental microvessels during pregnancy, discuss the pathogenic mechanisms underlying diseases such as preeclampsia, fetal growth restriction, and gestational diabetes, and summarize current clinical and research approaches for monitoring microvascular health. We also provide an update on research models for gestational microvascular complications and explore solutions to several unresolved challenges. With advancements in research techniques, we anticipate significant progress in understanding and managing these diseases, ultimately leading to new therapeutic strategies to improve maternal and fetal health.

Integrating microfluidic and bioprinting technologies: advanced strategies for tissue vascularization

Tissue engineering offers immense potential for addressing the unmet needs in repairing tissue damage and organ failure. Vascularization, the development of intricate blood vessel networks, is crucial for the survival and functions of engineered tissues. Nevertheless, the persistent challenge of ensuring an ample nutrient supply within implanted tissues remains, primarily due to the inadequate formation of blood vessels. This issue underscores the vital role of the human vascular system in sustaining cellular functions, facilitating nutrient exchange, and removing metabolic waste products. In response to this challenge, new approaches have been explored. Microfluidic devices, emulating natural blood vessels, serve as valuable tools for investigating angiogenesis and allowing the formation of microvascular networks. In parallel, bioprinting technologies enable precise placement of cells and biomaterials, culminating in vascular structures that closely resemble the native vessels. To this end, the synergy of microfluidics and bioprinting has further opened up exciting possibilities in vascularization, encompassing innovations such as microfluidic bioprinting. These advancements hold great promise in regenerative medicine, facilitating the creation of functional tissues for applications ranging from transplantation to disease modeling and drug testing. This review explores the potentially transformative impact of microfluidic and bioprinting technologies on vascularization strategies within the scope of tissue engineering.

Emerging Microfluidic Building Blocks for Cultured Meat Construction

Cultured meat aims to produce meat mass by culturing cells and tissues based on the muscle regeneration mechanism, and is considered an alternative to raising and slaughtering livestock. Hydrogel building blocks are commonly used as substrates for cell culture in tissue engineering and cultured meat because of their high water content, biocompatibility, and similar three-dimensional (3D) environment to the cellular niche in vivo. With the characteristics of precise manipulation of fluids, microfluidics exhibits advantages in the fabrication of building blocks with different structures and components, which have been widely applied in tissue regeneration. Microfluidic building blocks show promising prospects in the field of cultured meat; however, few reviews on the application of microfluidic building blocks in cultured meat have been published. This review outlines the recent status and prospects of the use of microfluidic building blocks in cultured meat. Starting with the introduction of cells and materials for cultured meat tissue construction, we then describe the diverse structures of the fabricated building blocks, including microspheres, microfibers, and microsphere-microfiber hybrid systems. Next, the stacking strategies for tissue construction are highlighted in detail. Finally, challenges and future prospects for developing microfluidic building blocks for cultured meat are discussed.

Controlling differentiation of stem cells via bioactive disordered cues

Ideal bone tissue engineering is to induce bone regeneration through the synergistic integration of biomaterial scaffolds, bone progenitor cells, and bone-forming factors. Biomimetic scaffolds imitate the native extracellular matrix (ECM) and are often utilized in vitro as analogues of the natural ECM to facilitate investigations of cell-ECM interactions and processes. In vivo, the cellular microenvironment has a crucial impact on regulating cell behavior and functions. A PET surface was activated and then functionalized with mimetic peptides to promote human mesenchymal stem cell (hMSC) adhesion and differentiation into an osteogenic lineage. Spray technology was used to randomly micropattern peptides (RGD and BMP-2 mimetic peptides) on the PET surface. The distribution of the peptides grafted on the surface, the roughness of the surfaces and the chemistry of the surfaces in each step of the treatment were ascertained by atomic force microscopy, fluorescence microscopy, time-of-flight secondary ion mass spectrometry, Toluidine Blue O assay, and X-ray photoelectron spectroscopy. Subsequently, cell lineage differentiation was evaluated by quantifying the expression of immunofluorescence markers: osteoblast markers (Runx-2, OPN) and osteocyte markers (E11, DMP1, and SOST). In this article, we hypothesized that a unique combination of bioactive micro/nanopatterns on a polymer surface improves the rate of morphology change and enhances hMSC differentiation. In DMEM, after 14 days, disordered micropatterned surfaces with RGD and BMP-2 led to a higher osteoblast marker expression than surfaces with a homogeneous dual peptide conjugation. Finally, hMSCs cultured in osteogenic differentiation medium (ODM) showed accelerated cell differentiation. In ODM, our results highlighted the expression of osteocyte markers when hMSCs were seeded on PET surfaces with random micropatterns.

Revolution in Flexible Wearable Electronics for Temperature and Pressure Monitoring—A Review

In the last few decades, technology innovation has had a huge influence on our lives and well-being. Various factors of observing our physiological characteristics are taken into account. Wearable sensing tools are one of the most imperative sectors that are now trending and are expected to grow significantly in the coming days. Externally utilized tools connected to any human to assess physiological characteristics of interest are known as wearable sensors. Wearable sensors range in size from tiny to large tools that are physically affixed to the user and operate on wired or wireless terms. With increasing technological capabilities and a greater grasp of current research procedures, the usage of wearable sensors has a brighter future. In this review paper, the recent developments of two important types of wearable electronics apparatuses have been discussed for temperature and pressure sensing (Psensing) applications. Temperature sensing (Tsensing) is one of the most important physiological factors for determining human body temperature, with a focus on patients with long-term chronic conditions, normally healthy, unconscious, and injured patients receiving surgical treatment, as well as the health of medical personnel. Flexile Psensing devices are classified into three categories established on their transduction mechanisms: piezoresistive, capacitive, and piezoelectric. Many efforts have been made to enhance the characteristics of the flexible Psensing devices established on these mechanisms.

Layer-by-layer assembly methods and their biomedical applications

Various biomedical applications arising due to the development of different LbL assembly methods with unique process properties.