Human mesenchymal stem cell (hMSC) differentiation towards cardiac cells using a new microbioanalytical method.

Stem cells (SCs) are more and more often applied in tissue engineering and cell therapies, e.g. in regenerative medicine. Standard methods of SC differentiation are time consuming and ineffective. Therefore, new bioanalytical methods (i.e. Lab-on-a-Chip systems) are develop to improve such type of studies. Although, microtechnology is a rapidly growing research area, there are so far not too many works which present SC differentiation into cardiomyocytes in the microsystems. Therefore, we present new microbioanalytical method of SC differentiation towards cardiac cells using a newly developed digitally controlled microdispenser integrated with a Heart-on-a-chip system. Seven-day culture of human mesenchymal stem cells (hMSCs) and their differentiation using biochemical factors such as 5-AZA (2 µM, 24 h) and VEGF (20 ng ml-1, 72 h) were investigated in the microsystem which was automatically operated using smartphone software. hMSC differentiation into the cardiac cells was confirmed using immunostaining of cardiac markers (α-actinin and troponin T). The usage of the microsystem allowed shortening the time of hMSC differentiation in comparison to macroscale method. We showed that the microsystem, in which the in vivo microenvironment is mimicked and dynamic conditions are provided by a microdispenser, favorably affect hMSC differentiation towards cardiac cells. Based on the presented research we can conclude that the developed digitally controlled microsystem could be successfully utilized as a new microbioanalytical method for stem cells differentiation and analysis of their function under dynamic conditions. In the future, this could be a helpful tool for scientists working on regenerative medicine.

First synthesis of cryptands with sucrose scaffold.

Cryptands with sucrose scaffold, an unknown class of such derivatives, were prepared from the readily available 2,3,3',4,4'-penta-O-benzylsucrose and 1',2,3,3',4,4'-hexa-O-benzylsucrose.

Diosgenyl 2-amino-2-deoxy-ß-D-galactopyranoside: synthesis, derivatives and antimicrobial activity.

The synthesis of diosgenyl 2-amino-2-deoxy-ß-D-galactopyranoside is presented for the first time. This synthetic saponin was transformed into its hydrochloride as well as N-acyl, 2-ureido, N-alkyl, and N,N-dialkyl derivatives. Antifungal and antibacterial studies show that some of the obtained compounds are active against Gram-positive bacteria and Candida type fungi.

Investigation of the Therapeutic Potential of New Antidiabetic Compounds Using Islet-on-a-Chip Microfluidic Model.

Nowadays, diabetes mellitus is one of the most common chronic diseases in the world. Current research on the treatment of diabetes combines many fields of science, such as biotechnology, transplantology or engineering. Therefore, it is necessary to develop new therapeutic strategies and preventive methods. A newly discovered class of lipids-Palmitic Acid Hydroxy Stearic Acid (PAHSA) has recently been proposed as an agent with potential therapeutic properties. In this research, we used an islet-on-a-chip microfluidic 3D model of pancreatic islets (pseudoislets) to study two isomers of PAHSA: 5-PAHSA and 9-PAHSA as potential regulators of proliferation, viability, insulin and glucagon expression, and glucose-stimulated insulin and glucagon secretion. Due to the use of the Lab-on-a-chip systems and flow conditions, we were able to reflect conditions similar to in vivo. In addition, we significantly shortened the time of pseudoislet production, and we were able to carry out cell culture, microscopic analysis and measurements using a multi-well plate reader at the same time on one device. In this report we showed that under microfluidic conditions PAHSA, especially 5-PAHSA, has a positive effect on pseudoislet proliferation, increase in cell number and mass, and glucose-stimulated insulin secretion, which may qualify it as a compound with potential therapeutic properties.

Visible-Light Responsive Sucrose-Containing Macrocyclic Host for Cations.

Chiral photoresponsive host 1 was prepared by a high-yield Cs2CO3-templated macrocyclization. Trans-1 transforms into long-lived cis-1 (25 days) upon irradiation with green light, and the backward transformation is triggered by blue light. Both isomers prefer potassium among alkali metal cations, and cis-1 binds cations stronger than trans-1 (Kcis/Ktrans ≤ 4.1). 1H NMR titration experiments as well as density functional theory studies reveal that sucrose ring oxygen residues and azobenzene nitrogen atoms in 1 contribute to cation coordination.

Islet-on-a-chip: Biomimetic micropillar-based microfluidic system for three-dimensional pancreatic islet cell culture.

Type 2 diabetes is currently one of the most common metabolic diseases, affecting all ages worldwide. As the incidence of type 2 diabetes increases, a growing number of studies focus on islets of Langerhans. A three-dimensional research model that maps islet morphology and maintains hormonal balance in vivo is still needed. In this work, we present an Islet-on-a-chip system, specifically a micropillar-based microfluidic platform for three-dimensional pancreatic islet cell culture and analysis. The microfluidic system consisted of two culture chambers that were equipped with 15 circular microtraps each, which were built with seven round micropillars each. Micropillars in the structure of microtraps supported cell aggregation by limiting the growth surface and minimizing wall shear stress, thereby ensuring proper medium diffusion and optimal culture conditions for cell aggregates. Our system is compatible with microwell plate readers and confocal laser scanning microscopes. Because of optimization of the immunostaining method, the appropriate cell distribution and high viability and proliferation up to 72 h of culture were confirmed. Enzyme-linked immunosorbent assays were performed to measure insulin and glucagon secretion after stimulation with different glucose concentrations. To our knowledge, this is the first Lab-on-a-chip system which enables the formation and three-dimensional culture of cell aggregates composed of commercially available α and ß pancreatic islet cells. The specific composition and arrangement of cells in the obtained model corresponds to the arrangement of the cells in rodent pancreatic islets in vivo. This Islet-on-a-chip system may be utilized to test pathogenic effectors and future therapeutic agents.

Combinations of regenerative medicine and Lab-on-a-chip systems: New hope to restoring the proper function of pancreatic islets in diabetes.

Cases of type 2 diabetes mellitus have significantly increased in recent years. Researchers worldwide are combining their knowledge of biology, medicine, tissue engineering, and microtechnology to develop new effective treatments. An important aspect of current research is to develop of a complete model of three-dimensional pancreatic islets to test various factors that affect disease development and evaluate new therapies and drugs. Several methods have allowed the development of three-dimensional research models. The use of Lab-on-a-chip systems with appropriate microstructure geometry is a promising solution to macroscale problems. Such a device allows the development of a complete platform reflecting conditions that prevail in the body. Organ-on-a-chip platforms are successfully used mainly in studies of lung, heart, and liver diseases. This review presents the current state of knowledge on the creation of three-dimensional pancreatic islet structures in both microscale and microfluidic systems. We highlight the most important aspects of developing the geometry of such devices. We also discuss analytical detection methods that are suitable for detecting hormones that are secreted from pancreatic islets and, in combination with appropriate Lab-on-a-chip systems, can be used as a Micro Total Analysis System (µTAS).

Biological characterization of the modified poly(dimethylsiloxane) surfaces based on cell attachment and toxicity assays.

Poly(dimethylsiloxane) (PDMS) is a material applicable for tissue and biomedical engineering, especially based on microfluidic devices. PDMS is a material used in studies aimed at understanding cell behavior and analyzing the cell adhesion mechanism. In this work, biological characterization of the modified PDMS surfaces based on cell attachment and toxicity assays was performed. We studied Balb 3T3/c, HMEC-1, and HT-29 cell adhesion on poly(dimethylsiloxane) surfaces modified by different proteins, with and without pre-activation with plasma oxygen and UV irradiation. Additionally, we studied how changing of a base and a curing agent ratios influence cell proliferation. We observed that cell type has a high impact on cell adhesion, proliferation, as well as viability after drug exposure. It was tested that the carcinoma cells do not require a highly specific microenvironment for their proliferation. Cytotoxicity assays with celecoxib and oxaliplatin on the modified PDMS surfaces showed that normal cells, cultured on the modified PDMS, are more sensitive to drugs than cancer cells. Cell adhesion was also tested in the microfluidic systems made of the modified PDMS layers. Thanks to that, we studied how the surface area to volume ratio influences cell behavior. The results presented in this manuscript could be helpful for creation of proper culture conditions during in vitro tests as well as to understand cell response in different states of disease depending on drug exposure.