Modeling of Artificial 3D Human Placenta

The placenta is the main organ that allows the fertilized oocyte to develop and mature. It allows the fetus to grow in the prenatal period by transferring oxygen and nutrients between the mother and the fetus. It acts as a basic endocrine organ which creates the physiological changes related to pregnancy and birth in the mother. Removal of wastes and carbon dioxide from the fetus is also achieved by the placenta. It prevents the rejection of the fetus and protects the fetus from harmful effects. Research on the human placenta focuses on understanding the placental structure and function to illuminate the complex structure of this important organ with technological advances. The structure and function of the placental barrier have been investigated with in vitro studies in 2D/3D, and various results have been published comparatively. In this review, we introduce the nature of the placenta with its 3D composition which has been called niche. Different cell types and placental structures are presented. We describe the systems and approaches used in the creation of current 3D placenta, placental transfer models as 3D placental barriers, and micro-engineered 3D placenta on-a-chip to explore complicated placental responses to nanoparticle exposure

The Effects of Grape Seed Oligomeric Proanthocyanidin and Nisin on Dental Pulp Stem Cells

Objective: This study aimed to evaluate the biological effects of “proanthocyanidin” (PA), and “nisin” (Ni), on dental pulp stem cells (DPSCs) and LPS-induced DPSCs as well as their antimicrobial effects against S. Aureus and E. coli. Materials and methods: After characterization of DPSCs, cytotoxicity of PA and Ni on DPSCs were evaluated using a water-soluble tetrazolium salt (WST-1). The cytokines and chemokines released by DPSCs and the expression levels of IL-6, IL-8, and TNF alpha were detected with human Cytokine Array C5 and enzyme-linked immunosorbent assay (ELISA), respectively. The antibacterial activities of PA and Ni were tested using the drop plate method. Results: PA at 75 μg/ml increased cell viability, decreased TNF-α expression of DPSCs, did not show any cytotoxic effects on LPS-induced DPSCs, and also showed a tendency to decrease TNF-α expression. PA at 75 μg/ml exhibited higher expressions of TIMP-2, OPG, IL-7, and IL-8 in LPS-induced DPSCs compared to DPSCs. Ni at 100 μg/ml decreased TNF-α expression in DPSCs with no cytotoxic effects. It provided increased cell viability and a downregulation trend of TNF-α expression in LPS-induced DPSCs. Both Ni and PA provided strong antibacterial effects against S. aureus. Ni at 200μg/ml had strong antibacterial effects against E. coli without affecting negatively the viability of both DPSCs and LPS-induced DPSCs and showed anti-inflammatory activity by decreasing TNF-α expression. PA provided strong antibac-terial effects against E. coli at 200 μg/ml but affected DPSCs viability negatively. Conclusion: PA and Ni at specific concentrations exhibited immunomodulatory activity on DPSCs and LPS-induced DPSCs without any cytotoxic effects and strong antibacterial effects on S. aureus

In situ formation of biocompatible and ductile protein-based hydrogels via Michael addition reaction and visible light crosslinking

Keratin, a biological polymer with high sulfur content, is the main component of hair, feathers and wool. Human hair is the cheapest natural source of keratin. In this study, an optimized and very effective reduction reaction method was used to obtain keratin from human hair. During this process, the disulfide bridge of keratin was reduced in the presence of sodium sulfide to form free sulfhydryl (thiols) that would act as a strong nucleophile. The results of FTIR spectroscopy, Tricine-SDS-PAGE and MALDI-TOF/MS verified the successful extraction of the reduced human hair keratin. A well-interconnected structure with three-dimensional (3D) scaffolds was prepared using keratin and methacrylated gelatin (GelMA), KeratinGel, for tissue engineering and other biomedical applications. KeratinGel hydrogels were in situ prepared via Michael addition reaction and visible light crosslinking. Two complementary crosslinking reactions were combined to enhance the network structure and provide ductility. With the targeted two-step method, the reactivity of vinyl groups of GelMA to photocrosslinking and thiol groups in keratin to the Michael addition reaction was exploited. Rheological monitoring of the Michael addition reaction was performed for KeratinGel hydrogels in a basic reaction environment at pH 7.4 with a constant concentration of GelMA (10% w/v) and different amounts of reduced human hair keratin (5, 7.5 and 10% w/v) at room temperature. The physical properties, swelling and degradation rates of KeratinGel hydrogels were determined to understand their suitability for tissue regeneration. We finalize that KeratinGel hydrogels would be better in minimally invasive surgeries, soft tissue engineering, especially with in situ gelling features, and favourable for the preparation of complex shapes and applications