bims-orenst Biomed News
on Organs-on-chips and engineered stem cell models
Issue of 2021‒01‒17
six papers selected by
Joram Mooiweer
University of Groningen


  1. ACS Biomater Sci Eng. 2019 Sep 09. 5(9): 4834-4843
    Mollica H, Palomba R, Primavera R, Decuzzi P.
      Metastases are the primary cause of death in cancer patients. Small animal models are helping in dissecting some key features in the metastatic cascade. Yet, tools for systematically analyzing the contribution of blood flow, vascular permeability, inflammation, tissue architecture, and biochemical stimuli are missing. In this work, a microfluidic chip is designed and tested to replicate in vitro key steps in the metastatic cascade. It comprises two channels, resting on the same plane, connected via an array of rounded pillars to form a permeable micromembrane. One channel acts as a vascular compartment and is coated by a fully confluent monolayer of endothelial cells, whereas the other channel is filled with a mixture of matrigel and breast cancer cells (MDA-MB-231) and reproduces the malignant tissue. The vascular permeability can be finely modulated by inducing pro-inflammatory conditions in the tissue compartment, which transiently opens up the tight junctions of endothelial cells. Permeability ranges from 1 μm/s (tight endothelium) to 5 μm/s (TNF-α at 50 ng/mL overnight) and up to ∼10 μm/s (no endothelium). Fresh medium flowing continuously in the vascular compartment is sufficient to induce cancer cell intravasation at rates of 8 cells/day with an average velocity of ∼0.5 μm/min. On the other hand, the vascular adhesion and extravasation of circulating cancer cells require TNF-α stimulation. Extravasation occurs at lower rates with 4 cells/day and an average velocity of ∼0.1 μm/min. Finally, the same chip is completely filled with matrigel and the migration of cancer cells from one channel to the other is monitored over a region of about 400 μm. Invasion rates of 12 cells/day are documented upon TNF-α stimulation. This work demonstrates that the proposed compartmentalized microfluidic chip can efficiently replicate in vitro, under controlled biophysical and biochemical conditions, the multiple key steps in the cancer metastatic cascade.
    Keywords:  cancer; cell migration; organ-on-a-chip; real-time cell microscopy; vascular inflammation
    DOI:  https://doi.org/10.1021/acsbiomaterials.9b00697
  2. ACS Biomater Sci Eng. 2019 Sep 09. 5(9): 4852-4860
    Hsieh HL, Nath P, Huang JH.
      Organ-on-a-chip, which mimics physiological functions of organs, is a potential tool for drug development and precision medicine. This chip, accompanied by a suitable culture environment and appropriate culture procedure, allows cells to form functional tissues that can be used in drug tests. Due to difficulties in the maintenance of cells and the complex nature of the tissue development process, it is essential to develop an automated culture platform to avoid contamination and reduce operational errors during long-term tissue culture. In this study, we developed a semiautomatic culture platform that integrates with a multistep fluidic control network, which allows multiple culture steps to be controlled and meets the requirement of the air-liquid interface (ALI), while maintaining a dynamic flow onto the cells. The culture platform was assembled with a culture chip, a reservoir, a miniaturized peristaltic pump, and a fluidic control base to connect each component and to operate the multiple culture steps. To demonstrate the capability of the culture platform, we have successfully controlled the multiple cell culture steps by switching the operation modes, allowing (1) cell proliferation under a liquid-liquid interface, (2) medium change from proliferation medium to differentiation medium, (3) cell differentiation under ALI conditions, and (4) repeated mucus washing. The dynamics and ALI culture conditions can simulate a physiological environment that is capable of maintaining and enabling cell differentiation for tissue-specific functions. The results demonstrate that bronchial tissue develops in the culture chip after 4 weeks of tissue culture. A versatile combination of culture steps makes the tissue culture platform suitable as an in vitro organ-on-a-chip culture model, especially for the tissues that involve the ALI culture, such as lung and skin. This platform, with multilogic control procedures, holds promise for enabling the long-term cultivation of differentiated tissues for advanced pharmacological and toxicological applications.
    Keywords:  air−liquid interface; culture platform; fluidic control; long-term tissue culture; organ-on-a-chip
    DOI:  https://doi.org/10.1021/acsbiomaterials.9b00912
  3. Biofabrication. 2021 Jan 13.
    Berger Fridman I, Ugolini GS, Vandelinder V, Cohen S, Konry T.
      Replication of physiological oxygen levels is fundamental for modeling human physiology and pathology in in vitro models. Environmental oxygen levels, applied in most in vitro models, poorly imitate the oxygen conditions cells experience in vivo, where oxygen levels average ~5%. Most solid tumors exhibit regions of hypoxic levels, promoting tumor progression and resistance to therapy. Though this phenomenon offers a specific target for cancer therapy, appropriate in vitro platforms are still lacking. Microfluidic models offer advanced spatio-temporal control of physico-chemical parameters. However, most of the systems described to date control a single oxygen level per chip, thus offering limited experimental throughput. Here, we developed a multi-layer microfluidic device coupling the high throughput generation of 3D tumor spheroids with a linear gradient of 5 oxygen levels, thus enabling multiple conditions and hundreds of replicates on a single chip. We showed how the applied oxygen gradient affects the generation of reactive oxygen species (ROS) and the cytotoxicity of Doxorubicin and Tirapazamine in breast tumor spheroids. Our results aligned with previous reports of increased ROS production under hypoxia and provide new insights on drug cytotoxicity levels that are closer to previously reported in vivo findings, demonstrating the predictive potential of our system.
    Keywords:  drug screening; hypoxia; microfluidics; spheroids; tumor microenvironment
    DOI:  https://doi.org/10.1088/1758-5090/abdb88
  4. Biomaterials. 2020 Dec 24. pii: S0142-9612(20)30871-1. [Epub ahead of print]269 120624
    Han W, El Botty R, Montaudon E, Malaquin L, Deschaseaux F, Espagnolle N, Marangoni E, Cottu P, Zalcman G, Parrini MC, Assayag F, Sensebe L, Silberzan P, Vincent-Salomon A, Dutertre G, Roman-Roman S, Descroix S, Camonis J.
      Bone is the most frequent metastasis site for breast cancer. As well as dramatically increasing disease burden, bone metastases are also an indicator of poor prognosis. One of the main challenges in investigating bone metastasis in breast cancer is engineering in vitro models that replicate the features of in vivo bone environments. Such in vitro models ideally enable the biology of the metastatic cells to mimic their in vivo behavior as closely as possible. Here, taking benefit of cutting-edge technologies both in microfabrication and cancer cell biology, we have developed an in vitro breast cancer bone-metastasis model. To do so we first 3D printed a bone scaffold that reproduces the trabecular architecture and that can be conditioned with osteoblast-like cells, a collagen matrix, and mineralized calcium. We thus demonstrated that this device offers an adequate soil to seed primary breast cancer bone metastatic cells. In particular, patient-derived xenografts being considered as a better approach than cell lines to achieve clinically relevant results, we demonstrate the ability of this biomimetic bone niche model to host patient-derived xenografted metastatic breast cancer cells. These patient-derived xenograft cells show a long-term survival in the bone model and maintain their cycling propensity, and exhibit the same modulated drug response as in vivo. This experimental system enables access to the idiosyncratic features of the bone microenvironment and cancer bone metastasis, which has implications for drug testing.
    Keywords:  3D-printing; Bone metastasis; Model; Patient-derived-xenograft
    DOI:  https://doi.org/10.1016/j.biomaterials.2020.120624
  5. Front Bioeng Biotechnol. 2020 ;8 568934
    Liu J, Zheng H, Dai X, Poh PSP, Machens HG, Schilling AF.
      Tissue engineering in combination with stem cell technology has the potential to revolutionize human healthcare. It aims at the generation of artificial tissues that can mimic the original with complex functions for medical applications. However, even the best current designs are limited in size, if the transport of nutrients and oxygen to the cells and the removal of cellular metabolites waste is mainly dependent on passive diffusion. Incorporation of functional biomimetic vasculature within tissue engineered constructs can overcome this shortcoming. Here, we developed a novel strategy using 3D printing and injection molding technology to customize multilayer hydrogel constructs with pre-vascularized structures in transparent Polydimethysiloxane (PDMS) bioreactors. These bioreactors can be directly connected to continuous perfusion systems without complicated construct assembling. Mimicking natural layer-structures of vascular walls, multilayer vessel constructs were fabricated with cell-laden fibrin and collagen gels, respectively. The multilayer design allows functional organization of multiple cell types, i.e., mesenchymal stem cells (MSCs) in outer layer, human umbilical vein endothelial cells (HUVECs) the inner layer and smooth muscle cells in between MSCs and HUVECs layers. Multiplex layers with different cell types showed clear boundaries and growth along the hydrogel layers. This work demonstrates a rapid, cost-effective, and practical method to fabricate customized 3D-multilayer vascular models. It allows precise design of parameters like length, thickness, diameter of lumens and the whole vessel constructs resembling the natural tissue in detail without the need of sophisticated skills or equipment. The ready-to-use bioreactor with hydrogel constructs could be used for biomedical applications including pre-vascularization for transplantable engineered tissue or studies of vascular biology.
    Keywords:  3D printing; PDMS; bioreactor; tissue engineering; vascularized hydrogels
    DOI:  https://doi.org/10.3389/fbioe.2020.568934
  6. Biomed Microdevices. 2021 Jan 11. 23(1): 7
    Ly KL, Rooholghodos SA, Rahimi C, Rahimi B, Bienek DR, Kaufman G, Raub CB, Luo X.
      Knowledge of human gingival cell responses to dental monomers is critical for the development of new dental materials. Testing standards have been developed to provide guidelines to evaluate biological functionality of dental materials and devices. However, one shortcoming of the traditional testing platforms is that they do not recapitulate the multi-layered configuration of gingiva, and thus cannot evaluate the layer-specific cellular responses. An oral mucosa-chip with two cell layers was previously developed as an alternative platform to assess the oral mucosa responses to dental biomaterials. The mucosa-chip consists of an apical keratinocyte layer attached to a fibroblast-embedded collagen hydrogel through interconnecting pores in a three-microchannel network. Here, cell responses in the mucosa-chip were evaluated against 2-hydroxyethyl methacrylate (HEMA), a common monomer used in restorative and aesthetic dentistry. The response of mucosal cell viability was evaluated by exposing the chip to HEMA of concentrations ranging from 1.56 to 25 mM and compared to cells in conventional well-plate monoculture. The co-cultured cells were then stained and imaged with epifluorescence and confocal microscopy to determine the layer-specific responses to the treatment. Mucosa-chips were demonstrated to be more sensitive to assess HEMA-altered cell viability than well-plate cultures, especially at lower doses (1.56 and 6.25 mM). The findings suggest that the mucosa-chip is a promising alternative to traditional platforms or assays to test a variety of biomaterials by offering a multi-layered tissue geometry, accessible layer-specific information, and higher sensitivity in detecting cellular responses.
    Keywords:  2-hydroxyethyl methacrylate; Cell viability; Dental materials testing; Gingiva; Mucosa-on-a-chip
    DOI:  https://doi.org/10.1007/s10544-021-00543-6