New biocompatible materials have enabled the direct 3D printing of complex functional living tissues, such as skeletal and cardiac muscle. Gelatinmethacryloyl (GelMA) is a photopolymerizable hydrogel composed of natural gelatin functionalized with methacrylic anhydride. However, it is difficult to obtain a single hydrogel that meets all the desirable properties for tissue engineering. In particular, GelMA hydrogels lack versatility in their mechanical properties and lasting 3D structures. In this work, a library of composite biomaterials to obtain versatile, lasting, and mechanically tunable scaffolds are presented. Two polysaccharides, alginate and carboxymethyl cellulose chemically functionalized with methacrylic anhydride, and a synthetic material, such as poly(ethylene glycol) diacrylate are combined with GelMA to obtain photopolymerizable hydrogel blends. Physical properties of the obtained composite hydrogels are screened and optimized for the growth and development of skeletal muscle fibers from C2C12 murine cells, and compared with pristine GelMA. All these composites show high resistance to degradation maintaining the 3D structure with high fidelity over several weeks. Altogether, in this study a library of biocompatible novel and totally versatile composite biomaterials are developed and characterized, with tunable mechanical properties that give structure and support myotube formation and alignment.

We proposed a facile, low cost, and green approach to produce stable aqueous graphene dispersions from graphite by sonication in aqueous bovine serum albumin (BSA) solution for biomedical applications. The production of high-quality graphene was confirmed using microscopy images, Raman spectroscopy, UV-vis spectroscopy, and XPS. In addition, ab initio calculations revealed molecular interactions between graphene and BSA. The processability of aqueous graphene dispersions was demonstrated by fabricating conductive and mechanically robust hydrogel-graphene materials.

Engineered muscle tissues demonstrate properties far from native muscle tissue. Therefore, fabrication of muscle tissues with enhanced functionalities is required to enable their use in various applications. To improve the formation of mature muscle tissues with higher functionalities, we co-cultured C2C12 myoblasts and PC12 neural cells. While alignment of the myoblasts was obtained by culturing the cells in micropatterned methacrylated gelatin (GelMA) hydrogels, we studied the effects of the neural cells (PC12) on the formation and maturation of muscle tissues. Myoblasts cultured in the presence of neural cells showed improved differentiation, with enhanced myotube formation. Myotube alignment, length and coverage area were increased. In addition, the mRNA expression of muscle differentiation markers (Myf-5, myogenin, Mefc2, MLP), muscle maturation markers (MHC-IId/x, MHC-IIa, MHC-IIb, MHC-pn, α-actinin, sarcomeric actinin) and the neuromuscular markers (AChE, AChR-ε) were also upregulated. All these observations were amplified after further muscle tissue maturation under electrical stimulation. Our data suggest a synergistic effect on the C2C12 differentiation induced by PC12 cells, which could be useful for creating improved muscle tissue. Copyright © 2014 John Wiley & Sons, Ltd.

Observing biochemical processes within living cell is imperative for biological and medical research. Fluoresce imaging is widely used for intracellular sensing of cell membranes, nuclei, lysosomes, and pH. Electrochemical assays have been proposed as an alternative to fluorescence‐based assays because of excellent analytical features of electrochemical devices. Notably, thanks to the rapid progress of micro/nanotechnologies and electrochemical techniques, intracellular electrochemical sensing is making rapid progress, leading to a successful detection of intracellular components. Such insight can provide a deep understanding of cellular biological processes and, ultimately, define the human healthy and diseased states. In this review, we present an overview of recent research progress in intracellular electrochemical sensing. We focus on two main topics, electrochemical extraction of cytosolic contents from cells and intracellular electrochemical sensing in situ.

3-Iodoindoles, 5-bromo-3-iodoindoles and 5-bromo-3-iodoindazoles have been studied with respect to their reactivity and selectivity in palladium catalyzed Sonogashira and Suzuki crosscoupling reactions. As a result, sequential Sonogashira-Sonogashira, Sonogashira-Suzuki, and Suzuki-Sonogashira reactions with 5-bromo-3-iodoindoles or indazoles were used to obtain a large range of new functionalized indoles and indazoles, which are potential 5-HT receptor ligands.

Non-alcoholic fatty liver disease (NAFLD) is characterized by lipid accumulation within the liver affecting 1 in 4 people worldwide. As the new silent killer of the twenty-first century, NAFLD impacts on both the request and the availability of new liver donors. The liver is the first line of defense against endogenous and exogenous metabolites and toxins. It also retains the ability to switch between different metabolic pathways according to food type and availability. This ability becomes a disadvantage in obesogenic societies where most people choose a diet based on fats and carbohydrates while ignoring vitamins and fiber. The chronic exposure to fats and carbohydrates induces dramatic changes in the liver zonation and triggers the development of insulin resistance. Common believes on NAFLD and different diets are based either on epidemiological studies, or meta-analysis, which are not controlled evidences; in most of the cases, they are biased on test-subject type and their lifestyles. The highest success in reverting NAFLD can be attributed to diets based on high protein instead of carbohydrates. In this review, we discuss the impact of NAFLD on body metabolic plasticity. We also present a detailed analysis of the most recent studies that evaluate high-protein diets in NAFLD with a special focus on the liver and the skeletal muscle protein metabolisms.

The limitations associated with the current in vivo and in vitro models are exemplified by the significant number of new drug candidates that fail to reach the market due to low efficiency or severe side effects in humans. These shortcomings, together with regulatory restrictions limiting the use of animal models, have generated interest in developing humanbased tissue-like constructs coupled with biosensor technologies (e.g., organs-on-achip, OOC) for disease modeling and drug and chemical testing. [1][2][3] To date, most of the OOC devices available represent a single organ, preventing investigations on systemic drug effects. Therefore, the current challenges of these microscale tissue analog systems attempt to improve the prediction of the effects of drugs and toxicity on various organs or tissues. This is especially important for studying multisystemic diseases when several tissues are closely related to the disease, as are skeletal muscle and pancreatic islets for diabetes mellitus (DM). In the present day, there are few examples of multi-organ devices representing various organs or tissues. We can find examples of multiple cell types (liver, tumor, and bone marrow or lung, kidney, and adipose cells) cultured in separate chambers interconnected and used to test the toxicity of drugs. [4,5] Or co-cultures for intestine, liver, and breast cancer cells to evaluate the intestinal absorption, hepatic metabolism, and drugs' anti-target cell bioactivity. [5] Notwithstanding the continued efforts and strong motivations to replace animal testing, these multi-organ systems are still in their infancy. Fully functional tissues have been recently incorporated into a multi-organ approach. [6] This device linked heart, liver, bone, and skin tissues by recirculating vascular flow to study pharmacokinetics and pharmacodynamic profiles. However, this device did not incorporate sensing technologies to monitor the metabolic dynamics of the tissues in real-time.DM comprises a group of chronic metabolic diseases characterized by hyperglycemia. DM is a major public health problem worldwide since the number of patients suffering increases every year. [7] Type 2 diabetes (T2D), the most common form of this disease, accounts for 90-95% of cases of DM. [8] T2D typically arises when peripheral metabolic tissues no longer respond to the insulin action to lower glucose levels in the blood. Skeletal muscle is one of the primary tissues targeted by insulin and is also involved in the glucose homeostasis Organ-on-a-chip (OOC) devices bring innovative disease modeling and drug discovery approaches by providing biomimetic models of tissues and organs in vitro combined with biosensors. Miniaturized biosensor systems and tissue biofabrication techniques allow to create multiple tissues on a chip highly controlling the experimental variables for high-content screening applications. In this work, a biomimetic multi-OOC integrated platform composed of skeletal muscle and pancreatic cells is fabricated to study the impact of exercise on insulin sec...

Microphysiological systems (MPS) or organs-on-chips (OoC) can emulate the physiological functions of organs in vitro and are effective tools for determining human drug responses in preclinical studies. However, the analysis of MPS has relied heavily on optical tools, resulting in difficulties in real-time and high spatial resolution imaging of the target cell functions. In this study, the role of scanning probe microscopy (SPM) as an analytical tool for MPS is evaluated. An access hole is made in a typical MPS system with stacked microchannels to insert SPM probes into the system. For the first study, a simple vascular model composed of only endothelial cells is prepared for SPM analysis. Changes in permeability and local chemical flux are quantitatively evaluated during the construction of the vascular system. The morphological changes in the endothelial cells after flow stimulation are imaged at the single-cell level for topographical analysis. Finally, the possibility of adapting the permeability and topographical analysis using SPM for the intestinal vascular system is further evaluated. It is believed that this study will pave the way for an in situ permeability assay and structural analysis of MPS using SPM.