Biocompatibility-on-a-chip: Characterization and evaluation of decellularized tendon extracellular matrix (tdECM) hydrogel for 3D stem cell culture in a microfluidic device.

Researchers have always tried expensive in vitro tests to show the 3D usability of dECM. The use of tissue-specific hydrogels in a microfluidic device is rarely studied. In this study, we have used ECM obtained from goat digital flexor tendons by decellularization technique. The tdECM was characterized for its structural properties using Scanning Electron Microscopy (SEM). Collagen, dsDNA, GAGs, and protein contents were quantified using spectrophotometric assays. The cell viability and proliferation of human umbilical cord-derived mesenchymal stem cells (hUMSCs) encapsulated in the tdECM hydrogel inside the microfluidic device were checked using Calcein-AM/PI. The FTIR data showed prominent peaks of the amide group, indicating the presence of collagen. The SEM data showed intact fiber morphology after the decellularization process. There was a 95 % reduction in double-stranded DNA (dsDNA) content, proving the effectiveness of the decellularization technique. There was no significant difference in the collagen content of tdECM and the GAGs were also in the acceptable range compared to the native tissue. Over 90 % cell viability in hUMSCs was observed qualitatively and quantitatively in vitro and inside a microfluidic device. In conclusion, we characterized the tdECM hydrogel and demonstrated its compatibility with the microfluidic device.

Indirect co-culture of lung carcinoma cells with hyperthermia-treated mesenchymal stem cells influences tumor spheroid growth in a collagen-based 3-dimensional microfluidic model.

BACKGROUND: Mesenchymal stem cells (MSCs) have paradoxically been reported to exert either pro- or anti-tumor effects in vitro. Hyperthermia, in combination with chemotherapy, has tumor-inhibiting effects; however, its role, together with MSCs, so far is not well understood. Furthermore, a lot of research is conducted using conventional 2-dimensional in vitro models that do not mimic the actual tumor microenvironment. AIM: In light of this fact, an indirect method of co-culturing human amniotic membrane-derived MSCs (AMMSCs) with collagen-encapsulated human lung carcinoma cells (A549) was performed using a 3-dimensional (3D) tumor-on-chip device. METHODS: The conditioned medium of AMMSCs (AMMSC-CM) or heat-treated AMMSCs (heat-AMMSC-CM) was utilized to create indirect co-culture conditions. Tumor spheroid growth characterization, immunocytochemistry and cytotoxicity assays, and anti-cancer peptide (P1) screening were performed to determine the effects of the conditioned medium. RESULTS: The A549 cells cultured inside the 3D microfluidic chip developed into multicellular tumor spheroids over five days of culture. The AMMSC-CM, contrary to previous reports claiming its tumor-inhibiting potential, led to significant proliferation of tumor spheroids. Heat-AMMSC-CM led to reductions in both spheroid diameter and cell proliferation. The medium containing the P1 peptide was found to be the least cytotoxic to tumor spheroids in co-culture compared with the monoculture and heat-co-culture groups. CONCLUSIONS: Hyperthermia, in combination with the anticancer peptide, exhibited highest cytotoxic effects. This study highlights the growing importance of 3D microfluidic tumor models for testing stem-cell-based and other anti-cancer therapies.

Selective Cytotoxicity of a Novel Trp-Rich Peptide against Lung Tumor Spheroids Encapsulated inside a 3D Microfluidic Device.

There is a globally rising healthcare need to develop new anticancer therapies as well as to test them on biologically relevant in vitro cancer models instead of overly simplistic 2D models. To address both these needs, a 3D lung cancer spheroid model is developed using human A549 cells trapped inside a collagen gel in a compartmentalized microfluidic device and homogenously sized (35-45 µm) multicellular tumor spheroids are obtained in 5 days. The novel tryptophan-rich peptide P1, identified earlier as a potential anticancer peptide (ACP), shows enhanced cytotoxic efficacy against A549 tumor spheroids (>75%) in clinically relevant low concentrations, while it does not affect human amniotic membrane mesenchymal stem cells at the same concentrations (<15%). The peptide also inhibits the formation of tumor spheroids by reducing cell viability as well as lowering the proliferative capacity, which is confirmed by the expression of cell proliferation marker Ki-67. The ACP offers a novel therapeutic strategy against lung cancer cells without affecting healthy cells. The microfluidic device used is likely to be useful in helping develop models for several other cancer types to test new anticancer agents.

Isogenic-induced endothelial cells enhance osteogenic differentiation of mesenchymal stem cells on silk fibroin scaffold.

Aim: We investigated the role of induced endothelial cells (iECs) in mesenchymal stem cells (MSCs)/iECs co-culture and assessed their osteogenic ability on silk fibroin nanofiber scaffolds. Methods: The osteogenic differentiation was assessed by the ALP assay, calcium assay and gene expression studies. Results: The osteogenic differentiation of the iECs co-cultures was found to be higher than the MSCs group and proximal to endothelial cells (ECs) co-cultures. Furthermore, the usage of isogenic iECs for co-culture increased the osteogenic and endothelial gene expression. Conclusion: These findings suggest that iECs mimic endothelial cells when co-cultured with MSCs and that one MSCs source can be used to give rise to both MSCs and iECs. The isogenic MSCs/iECs co-culture provides a new option for bone tissue engineering applications.

On-chip anticancer drug screening - Recent progress in microfluidic platforms to address challenges in chemotherapy.

There is an increasing need for advanced and inexpensive preclinical models to accelerate the development of anticancer drugs. While costly animal models fail to predict human clinical outcomes, in vitro models such as microfluidic chips ('tumor-on-chip') are showing tremendous promise at predicting and providing meaningful preclinical drug screening outcomes. Research on 'tumor-on-chips' has grown enormously worldwide and is being widely accepted by pharmaceutical companies as a drug development tool. In light of this shift in philosophy, it is important to review the recent literature on microfluidic devices to determine how rapidly the technology has progressed as a promising model for drug screening and aiding cancer therapy. We review the past five years of successful developments and capabilities in microdevice technology (cancer models) for use in anticancer drug screening. Microfluidic devices that are being designed to address current challenges in chemotherapy, such as drug resistance, combinatorial drug therapy, personalized medicine, and cancer metastasis are also reviewed in detail. We provide a perspective on how personalized 'tumor-on-chip', as well as high-throughput microfluidic platforms based on patient-specific tumor cells, can potentially replace the more expensive and 'non-human' animal models in preclinical anticancer drug development.