Organs-on-a-chip最新文献

With the approval of the Food and Drug (FDA) Modernization Act 2.0, the pharmaceutical industry is poised to expand its research components with a plethora of alternative models, including organ-on-microfluidic chips in pharma and biotechnology, resulting in a personalized approach. Microfluidics opens new possibilities for the study of cell biology, especially for a better understanding of cell-cell interactions and the pathophysiology of neurodegenerative diseases in vitro, and the use of these models to assess the efficacy of novel therapies is promising. These thumb-sized organ-on-a-chip systems have the potential to reduce animal testing and replace simple 2D culture systems that do not succeed to resemble the complex physiology of tissues and organs. Restoring critical aspects of endothelial-brain immune cell communication in a biomimetic system using microfluidics may accelerate the process of central nervous system (CNS) drug discovery and improve our understanding of the mechanisms of multiple neurodegenerative diseases. In addition, these organ-on-chip technologies can be used to optimize drug targets and assess drug efficacy and toxicity in real-time, which can significantly help minimize animal testing requirements, as authorized by the recent FDA Act. This Review initially summarizes the fundamental advantages of microfluidic systems in creating a compartmentalized cell culture for the complex three-dimensional architectures of neural tissue cells such as neurons, glial cells, and endothelial cells, and their ability to recapitulate the spatiotemporal biophysicochemical gradients and mechanical microenvironments. Then, brain endothelial cell-astroglia-on-a-chip models with a focus on neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis are introduced. Finally, the current limitations of these microfluidic devices and strategies to overcome them are discussed.

Microphysiological systems (MPS) incorporate physiologically relevant microanatomy, mechanics, and cells to mimic tissue function. Reproducible and standardized in vitro models of tissue barriers, such as the blood-tissue interface (BTI), are critical for next-generation MPS applications in research and industry. Many models of the BTI are limited by the need for semipermeable membranes, use of homogenous cell populations, or 2D culture. These factors limit the relevant endothelial-epithelial contact and 3D transport, which would best mimic the BTI. Current models are also difficult to assemble, requiring precise alignment and layering of components. The work reported herein details the engineering of a BTI-on-a-chip (BTI Chip) that addresses current disadvantages by demonstrating a single layer, membrane-free design. Laminar flow profiles, photocurable hydrogel scaffolds, and human cell lines were used to construct a BTI Chip that juxtaposes an endothelium in direct contact with a 3D engineered tissue. A biomaterial composite, gelatin methacryloyl and 8-arm polyethylene glycol thiol, was used for in situ fabrication of a tissue structure within a Y-shaped microfluidic device. To produce the BTI, a laminar flow profile was achieved by flowing a photocurable precursor solution alongside phosphate buffered saline. Immediately after stopping flow, the scaffold underwent polymerization through a rapid exposure to UV light (<300 mJ/cm²). After scaffold formation, blood vessel endothelial cells were introduced and allowed to adhere directly to the 3D tissue scaffold, without barriers or phase guides. Fabrication of the BTI Chip was demonstrated in both an epithelial tissue model and blood-brain barrier (BBB) model. In the epithelial model, scaffolds were seeded with human dermal fibroblasts. For the BBB models, scaffolds were seeded with the immortalized glial cell line, SVGP12. The BTI Chip microanatomy was analyzed post facto by immunohistochemistry, showing the uniform production of a patent endothelium juxtaposed with a 3D engineered tissue. Fluorescent tracer molecules were used to characterize the permeability of the BTI Chip. The BTI Chips were challenged with an efflux pump inhibitor, cyclosporine A, to assess physiological function and endothelial cell activation. Operation of physiologically relevant BTI Chips and a novel means for high-throughput MPS generation was demonstrated, enabling future development for drug candidate screening and fundamental biological investigations.

Disease models that can accurately recapitulate human pathophysiology during infection and clinical response to antiviral therapeutics are still lacking, which represents a major barrier in drug development. The emergence of human Organs-on-a-Chip that integrated microfluidics with three-dimensional (3D) cell culture, may become the potential solution for this urgent need. Human Organs-on-a-Chip aims to recapitulate human pathophysiology by incorporating tissue-relevant cell types and their microenvironment, such as dynamic fluid flow, mechanical cues, tissue–tissue interfaces, and immune cells to increase the predictive validity of in vitro experimental models. Human Organs-on-a-Chip has a broad range of potential applications in basic biomedical research, preclinical drug development, and personalized medicine. This review focuses on its use in the fields of virology and infectious diseases. We reviewed various types of human Organs-on-a-Chip-based viral infection models and their application in studying viral life cycle, pathogenesis, virus-host interaction, and drug responses to virus- and host-targeted therapies. We conclude by proposing challenges and future research avenues for leveraging this promising technology to prepare for future pandemics.

Over the past decades, the pre-clinical evaluation of new drugs requires toxicological screening in animal models. The development of non-animal and nonclinical screening models could potentially play a role in the prediction of human pharmacokinetics of new drug candidates. In this study, we established stable organoids of the cynomolgus monkey airway, liver ductal, and kidney that could be passaged and cryopreserved. Drug sensitivity analyses revealed that very low doses of gemcitabine and 5-fluorouridine were toxic to the airway, liver ductal, and kidney organoids. Only high doses of regorafenib were toxic to liver ductal organoids while airway organoids were resistant to all doses of pemetrexed. These organoids showed tissue-specific expression of drug-metabolizing enzymes and drug transporter genes with liver ductal organoids exhibiting the most significant expression of all drug-metabolizing enzymes and transporters. The systematic evaluation of the pharmacokinetic functions of the cynomolgus monkey kidney, liver ductal, and airway organoids could find application in the pre-clinical toxicological studies of new drugs.

As a natural dynamic barrier separating blood from brain parenchyma, the blood–brain barrier (BBB) is mainly composed of brain microvascular endothelial cells (BMECs), pericytes, astrocytes, and a variety of neurons. The BBB regulates the highly selective transport of various substances between the brain and blood and maintains the stability of the central nervous system (CNS). Owing to this tight control, the BBB represents a formidable challenge for the delivery of drugs and other exogenous compounds into the CNS, which has bottlenecked the development of many drugs for CNS diseases. Therefore, efficient and precise in vitro models of the BBB are needed to assess the efficacy and toxicity of drugs targeting the CNS to inform drug design and to improve the success rate of agents that enter clinical evaluation. In vitro BBB models have rapidly advanced from the early two-dimensional (2D) static models to the current three-dimensional (3D) dynamic microfluidic chips. Although the commonly used, static, in vitro BBB models are simple to construct and TEER values are convenient to detect, the static models do not provide an ideal (i.e., accurate) BBB environment, since they lack the correct physiological size/scale and hemodynamic shear stress, both of which play substantial roles in promoting and maintaining EC differentiation into a specific BBB phenotype. Compared with traditional static models, 3D microfluidic models thus enable cells to react in a manner more closely resembling in vivo behavior by simulating a microenvironment with more natural signal transduction. As a result, the dynamic 3D BBB model can more accurately recapitulate the structure and function of the human BBB. Here we summarize the recent progress in in vitro microfluidic BBB chips and their research applications as well as discuss the prospects and challenges for where the technology is headed.

Breast organoids and breast cancer organoids have been a crucial tool for mammary gland and breast cancer research. In the last several years, breast cancer organoids have shown tremendous potentials for largely mimicking the structural and functional features of the original breast cancer tissue. In this review, the cell source and strategy for generating breast cancer organoids will be introduced. Then, the current progress of breast cancer organoids will be summarized, including disease model, living biobank, drug screening and personalized therapy. Ultimately, we will discuss the future opportunities and challenges of current breast cancer organoids from basic to clinical.

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2, is a systemic disease with a broad spectrum of manifestations in multiple organs. Till now, it remains unclear whether these multi-organ dysfunctions arise from direct viral infection, or indirect injuries. There is an urgent need to evaluate the impacts of SARS-CoV-2 infection on human bodies and explore the pathogenesis of extrapulmonary organ injuries at a systemic level. Multi-organ microphysiological systems, which can model whole-body physiology with engineered tissues and physiological communications between different organs, serve as powerful platforms to model COVID-19 in a multi-organ manner. In this perspective, we summarize the recent advancement in multi-organ microphysiological system-based researches, discuss the remaining challenges, and proposed some prospects in the application of multi-organ model system for COVID-19 research.

Microperforated membranes are essential components of various organ-on-a-chip (OOC) barrier models developed to study transport of molecular compounds and cells across cell layers in e.g. the intestine and blood-brain barrier. These OOC membranes have two functions: 1) to support growth of cells on one or both sides, and 2) to act as a filter-like barrier to separate adjacent compartments. Thin, microperforated poly(dimethylsiloxane) (PDMS) membranes can be fabricated by micromolding from silicon molds comprising arrays of micropillars for the formation of micropores. However, these molds are made by deep reactive ion etching (DRIE) and are expensive to fabricate. We describe the micromolding of thin PDMS membranes with easier-to-make, SU-8 epoxy photoresist molds. With a multilayer, SU-8, pillar microarray mold, massively parallel arrays of micropores can be formed in a thin layer of PDMS, resulting in a flexible barrier membrane that can be easily incorporated and sealed between other layers making up the OOC device. The membranes we describe here have a 30-μm thickness, with 12-μm-diameter circular pores arranged at a 100-μm pitch in a square array. We show application of these membranes in gut-on-a-chip devices, and expect that the reported fabrication strategy will also be suitable for other membrane dimensions.

Traditional in vitro models and animal models often lack the physiological complexity or the accuracy to obtain predictive responses that are clinically translatable to humans. With the advent of microphysiological systems over recent years, new models that are able to mimic human biology more closely have been developed. The culture of whole tissue samples within microfluidic devices promises to bridge preclinical and clinical research, and has the potential to be applied in personalised medicine, environmental sciences or the food industry. However, many challenges must be addressed in terms of tissue maintenance ex vivo or methods for analysing samples, particularly in real-time. In this review, we explore the microfluidic strategies that have been reported for the culture of tissue biopsies ex vivo and the different techniques that have been explored in order to expand their life span, control the microenvironment and interrogate the samples. Current challenges facing the field are also discussed.