bims-orenst 2022-08-28 papers

Issue of 2022–08–28
five papers selected by

Micromachines (Basel). 2022 Aug 20. pii: 1359. [Epub ahead of print]13(8):

Pressure-Driven Perfusion System to Control, Multiplex and Recirculate Cell Culture Medium for Organs-on-Chips.

Mees N S de Graaf, Aisen Vivas, Andries D van der Meer, Christine L Mummery, Valeria V Orlova.

Organ-on-chip (OoC) devices are increasingly used to mimic the tissue microenvironment of cells in intact organs. This includes microchannels to mimic, for example, fluidic flow through blood vessels. Present methods for controlling microfluidic flow in these systems rely on gravity, rocker systems or external pressure pumps. For many purposes, pressure pumps give the most consistent flow profiles, but they are not well-suited for high throughput as might be required for testing drug responses. Here, we describe a method which allows for multiplexing of microfluidic channels in OoC devices plus the accompanying custom software necessary to run the system. Moreover, we show the approach is also suitable for recirculation of culture medium, an essential cost consideration when expensive culture reagents are used and are not "spent" through uptake by the cells during transient unidirectional flow.

Keywords: fluidic circuit board (FCB); multiplexing; organ-on-a-chip (OoC); perfusion; recirculation; vessels-on-chip (VoC)

DOI: https://doi.org/10.3390/mi13081359

Biosensors (Basel). 2022 Aug 09. pii: 618. [Epub ahead of print]12(8):

Exploratory Evaluation of EGFR-Targeted Anti-Tumor Drugs for Lung Cancer Based on Lung-on-a-Chip.

Jianfeng Tan, Xindi Sun, Jianhua Zhang, Huili Li, Jun Kuang, Lulu Xu, Xinghua Gao, Chengbin Zhou.

In this study, we used three-dimensional (3D) printing to prepare a template of a microfluidic chip from which a polydimethylsiloxane (PDMS)lung chip was successfully constructed. The upper and lower channels of the chip are separated by a microporous membrane. The upper channel is seeded with lung cancer cells, and the lower channel is seeded with vascular endothelial cells and continuously perfused with cell culture medium. This lung chip can simulate the microenvironment of lung tissue and realize the coculture of two kinds of cells at different levels. We used a two-dimensional (2D) well plate and a 3D lung chip to evaluate the effects of different EGFR-targeting drugs (gefitinib, afatinib, and osimertinib) on tumor cells. The 3D lung chip was superior to the 2D well plate at evaluating the effect of drugs on the NCI-H650, and the results were more consistent with existing clinical data. For primary tumor cells, 3D lung chips have more advantages because they simulate conditions that are more similar to the physiological cell microenvironment. The evaluation of EGFR-targeted drugs on lung chips is of great significance for personalized diagnosis and treatment and pharmacodynamic evaluation.

Keywords: EGFR; drug evaluation; lung cancer; lung-on-a-chip; targeted therapy

DOI: https://doi.org/10.3390/bios12080618

Biomaterials. 2022 Aug 15. pii: S0142-9612(22)00369-6. [Epub ahead of print] 121729

A human model of arteriovenous malformation (AVM)-on-a-chip reproduces key disease hallmarks and enables drug testing in perfused human vessel networks.

Kayla Soon, Mengyuan Li, Ruilin Wu, Angela Zhou, Negar Khosraviani, Williamson D Turner, Joshua D Wythe, Jason E Fish, Sara S Nunes.

Brain arteriovenous malformations (AVMs) are a disorder wherein abnormal, enlarged blood vessels connect arteries directly to veins, without an intervening capillary bed. AVMs are one of the leading causes of hemorrhagic stroke in children and young adults. Most human sporadic brain AVMs are associated with genetic activating mutations in the KRAS gene. Our goal was to develop an in vitro model that would allow for simultaneous morphological and functional phenotypic data capture in real time during AVM disease progression. By generating human endothelial cells harboring a clinically relevant mutation found in most human patients (activating mutations within the small GTPase KRAS) and seeding them in a dynamic microfluidic cell culture system that enables vessel formation and perfusion, we demonstrate that vessels formed by KRAS4AG12V mutant endothelial cells (ECs) were significantly wider and more leaky than vascular beds formed by wild-type ECs, recapitulating key structural and functional hallmarks of human AVM pathogenesis. Immunofluorescence staining revealed a breakdown of adherens junctions in mutant KRAS vessels, leading to increased vascular permeability, a hallmark of hemorrhagic stroke. Finally, pharmacological blockade of MEK kinase activity, but not PI3K inhibition, improved endothelial barrier function (decreased permeability) without affecting vessel diameter. Collectively, our studies describe the creation of human KRAS-dependent AVM-like vessels in vitro in a self-assembling microvessel platform that is amenable to phenotypic observation and drug delivery.

DOI: https://doi.org/10.1016/j.biomaterials.2022.121729

Biomaterials. 2022 Aug 16. pii: S0142-9612(22)00368-4. [Epub ahead of print] 121728

Omentum-on-a-chip: A multicellular, vascularized microfluidic model of the human peritoneum for the study of ovarian cancer metastases.

Lina I Ibrahim, Cynthia Hajal, Giovanni S Offeddu, Mark R Gillrie, Roger D Kamm.

Epithelial ovarian cancer has the highest mortality rate of any gynecologic malignancy and most frequently metastasizes to the peritoneal cavity. Intraperitoneal metastases are highly associated with ascites, the pathologic accumulation of peritoneal fluid due to impaired drainage, increased peritoneal permeability, and tumor and stromal cytokine secretion. However, the relationship between ascites, vascular and mesothelial permeability, and ovarian cancer intraperitoneal metastases remains poorly understood. In this study, a vascularized in vitro model of the human peritoneal omentum and ovarian tumor microenvironment (TME) was employed to study stromal cell effects on tumor cell (TC) attachment and growth, as well as TC effects on vascular and mesothelial permeability in models of both early- and late-stage metastases. Control over the number of TCs seeded in the vascularized peritoneum revealed a critical cell density requirement for tumor growth, which was further enhanced by stromal adipocytes and endothelial cells found in the peritoneal omentum. This tumor growth resulted in both a physically-mediated decrease and cytokine-mediated increase in microvascular permeability, emphasizing the important and potentially opposing roles of tumor cells in ascites formation. This system provides a robust platform to elucidate TC-stromal cell interactions during intraperitoneal metastasis of ovarian cancer and presents the first in vitro vascularized model of the human peritoneum and ovarian cancer TME.

Keywords: Microvascular networks; Peritoneum and omentum in vitro model; Tumor cell attachment and invasion; Vascular and mesothelial permeability; Vascularized adipose microfluidic tissue model

DOI: https://doi.org/10.1016/j.biomaterials.2022.121728

Front Oncol. 2022 ;12 959299

Design and Fabrication of a Liver-on-a-chip Reconstructing Tissue-tissue Interfaces.

Jing Liu, Chong Feng, Min Zhang, Feng Song, Haochen Liu.

Despite the rapid advances in the liver-on-a-chip platforms, it remains a daunting challenge to construct a biomimetic liver-on-a-chip for in vitro research. This study aimed to reconstruct the tissue-tissue interfaces based on bilayer microspheres and form vascularized liver tissue. Firstly, we designed a tri-vascular liver-on-a-chip (TVLOC) comprising a hepatic artery, a portal vein and a central vein, and theoretically analyzed the distribution of velocity and concentration fields in the culture area. Secondly, we designed a bilayer microsphere generating microsystem based on the coaxial confocal principle, which is primarily used to produce bilayer microspheres containing different kinds of cells. Finally, the bilayer microspheres were co-cultured with endothelial cells in the cell culture area of the TVLOC to form vascularized liver tissue, and the cell viability and vascular network growth were analyzed. The results revealed that the TVLOC designed in this study can provide a substance concentration gradient similar to that of the liver microenvironment, and the bilayer microspheres can form a three-dimensional (3D) orderly liver structure with endothelial cells. Such a liver-on-a-chip is capable of maintaining the function of hepatocytes (HCs) pretty well. This work provides full insights into further simulation of the liver-on-a-chip.

Keywords: bilayer microspheres; organ-on-chip; substance concentration gradient; tissue-tissue interfaces; vascularized liver tissue

DOI: https://doi.org/10.3389/fonc.2022.959299