Evaluating the impact of perfusion on nanomaterial uptake rates and cytotoxicity using microfluidic in vitro & in silico cell cultures systems

In the last decade, the application of nanomaterials (NMs) in technical products and biomedicine has become a rapidly increasing market trend. As the safety and efficacy of NMs are of utmost importance, new methods are needed to study the dynamic interactions of NMs at the nano-biointerface. However, evaluation of NMs based on standard and static cell culture end-point detection methods does not provide information on the dynamics of living biological systems, which is crucial for the understanding of physiological responses. To gain a deeper understanding of nanomaterial – cell interactions under perfused conditions, we here present a combinatorial in vitro & in silico approach to describe shear-force dependent uptake of nanoparticles on vascular endothelial cells. Additionally, we present a microsensor-integrated microfluidic system capable of monitoring the enhanced cytotoxic effects of nanodrugs on lung cells following chronic and acute exposure scenarios. Result of our study demonstrate that both active uptake rates and cytotoxicity of nanomaterials are strongly modulated by flow velocity and local shear-force conditions. Please click Additional Files below to see the full abstract

Monitoring of metabolic parameters of mammal cells cultures in microfluidic devices using integrated optical chemical sensors

Optical chemical sensors are well established in the chemical industry, life science, biotechnology and research laboratories. They are operate non-invasive, do not need any reference elements and can be read-out via contactless measurement. Moreover, it is possible to miniaturize and integrate them into microfluidic systems. Due to their simple composition, optical sensors can be produced at low price and therefore represent a good alternative compared to electrochemical sensors for their application in disposable microfluidics. The various possibilities of integrated optical oxygen sensors have already shown their potential in different microfluidic applications [1]. However, monitoring of further metabolic parameters is important for a better understanding of biological processes. Therefore, our group develops, next to oxygen sensors, also optical sensors for monitoring pH, glucose, CO2, ammonia and various ions. Still, integration in a Lab-on-a-chip format is a challenging task due to the state-of-the-art performances in terms of signal brightness, response times, optoelectronic read-out systems, fabrication and integration. Please click Additional Files below to see the full abstrac

Laser-based 3D printing of hydrogel barrier models for microfludic applications

The placenta secures the survival and development of the fetus. As placental tissue connects the fetus with the mother and is responsible for endogenous and exogenous material transfer. The maternal and fetal blood are thereby separated, by the so-called placental barrier, which is made up by the trophoblastic syncytium and the fetal capillary wall. Research in the field of placenta biology represents a challenging topic, as current approaches are difficult to perform, time consuming and often carry the risk of harming the fetus. The establishment of a reproducible in-vitro model, simulating the placental transport is necessary to study fetal development and for identification of underlying causes of maldevelopment. In this study, a photosensitive hydrogel material, in combination with two-photon polymerisation, was used to produce high resolution structures with nanometre precision geometries. Gelatine modified with methacrylamide and amino-ethyl-methacrylate (GelMOD AEMA) was thereby crosslinked within a customised microfluidic-device under the addition of photoinitiator, separating the chip in two different compartments (Figure 1). The fetal compartment contains HUVEC cells which are cultivated in EGM2, while BeWo B30 cells are supplied with DMEM Ham-F12 to mimic the maternal compartment. This microfluidic approach in combination with native flow profiles can be used to precisely remodel the microenvironment of placental tissue. The establishment of a functional placenta-on-a-chip-model allows the modulation of different clinical and biological scenarios in the future. A potential application can be found in the simulation of altered sugar transport across the placental membrane and evaluation of the effects of altered nutrient balance in-utero Please click Additional Files below to see the full abstract

Fabrication of biomimetic placental barrier structures within a microfluidic device utilizing two-photon polymerization

The placenta is a transient organ, essential for development and survival of the unborn fetus. It interfaces the body of the pregnant woman with the unborn child and secures transport of endogenous and exogenous substances. Maternal and fetal blood are thereby separated at any time, by the so-called placental barrier. Current in vitro approaches fail to model this multifaceted structure, therefore research in the field of placental biology is particularly challenging. The present study aimed at establishing a novel model, simulating placental transport and its implications on development, in a versatile but reproducible way. The basal membrane was replicated using a gelatin-based material, closely mimicking the composition and properties of the natural extracellular matrix. The microstructure was produced by using a high-resolution 3D printing method - the two-photon polymerization (2PP). In order to structure gelatin by 2PP, its primary amines and carboxylic acids are modified with methacrylamides and methacrylates (GelMOD-AEMA), respectively. High-resolution structures in the range of a few micrometers were produced within the intersection of a customized microfluidic device, separating the x-shaped chamber into two isolated cell culture compartments. Human umbilical-vein endothelial cells (HUVEC) seeded on one side of this membrane simulate the fetal compartment while human choriocarcinoma cells, isolated from placental tissue (BeWo B30) mimic the maternal syncytium. This barrier model in combination with native flow profiles can be used to mimic the microenvironment of the placenta, investigating different pharmaceutical, clinical and biological scenarios. As proof-of-principle, this bioengineered placental barrier was used for the investigation of transcellular transport processes. While high molecular weight substances did not permeate, smaller molecules in the size of glucose were able to diffuse through the barrier in a time-depended manner. We envision to apply this bioengineered placental barrier for pathophysiological research, where altered nutrient transport is associated with health risks for the fetus

FTIR spectroscopy as a novel analytical approach for investigation of glucose transport and glucose transport inhibition studies in transwell in vitro barrier models

The final publication is available via https://doi.org/10.1016/j.saa.2020.118388.Glucose transport is key for cellular metabolism as well as physiological function and is maintained via passive facilitated and active sodium-glucose linked transport routes. Here, we present for the first time Fouriertransform infrared spectroscopy as a novel approach for quantification ofapical-to-basolateral glucose transport ofin vitro cell barriermodels using liver, lung, intestinal and placental cancer cell lines. Results ofour comparative study revealed that distinct differences could be observed upon subjection to transport inhibitors.European Research Counci

A lab-on-a-chip system with an embedded porous membrane-based impedance biosensor array for nanoparticle risk assessment on placental Bewo trophoblast cells

The human placenta is a unique organ serving as the lung, gut, liver, and kidney of the fetus, mediating the exchange of different endogenous as well as exogenous substances and gases between the mother and fetus during pregnancy. Additionally, the placental barrier protects the fetus from a range of environmental toxins, bacterial and viral infections, since any contaminant bridging the placenta may have unforeseeable effects on embryonal and fetal development. A more recent concern in placenta research, however, involves the ability of engineered nanoparticles to cross the placental barrier and/or affect its barrier function. To advance nanoparticle risk assessment at the human placental barrier, we have developed as proof-of-principle a highly integrated placenta-on-a-chip system containing embedded membrane-bound impedance microsensor arrays capable of non-invasively monitoring placental barrier integrity. Barrier integrity is continuously and label-free evaluated using porous membrane-based interdigitated electrode structures located on top of a porous PET membrane supporting a barrier of trophoblast-derived BeWo cell barrier in the absence and presence of standardized silicon dioxide (SiO2), titanium dioxide (TiO2), and zinc oxide (ZnO) nanomaterials.This work has been funded by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 685817.Peer reviewe

Engineering of three-dimensional pre-vascular networks within fibrin hydrogel constructs by microfluidic control over reciprocal cell signaling

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in B. Bachmann et. al., Biomicrofluidics 12, 042216 (2018) and may be found at https://doi.org/10.1063/1.5027054

Microfluidic and Lab-on-a-Chip Systems for Cutaneous Wound Healing Studies

Cutaneous wound healing is a complex, multi-stage process involving direct and indirect cell communication events with the aim of efficiently restoring the barrier function of the skin. One key aspect in cutaneous wound healing is associated with cell movement and migration into the physically, chemically, and biologically injured area, resulting in wound closure. Understanding the conditions under which cell migration is impaired and elucidating the cellular and molecular mechanisms that improve healing dynamics are therefore crucial in devising novel therapeutic strategies to elevate patient suffering, reduce scaring, and eliminate chronic wounds. Following the global trend towards the automation, miniaturization, and integration of cell-based assays into microphysiological systems, conventional wound healing assays such as the scratch assay and cell exclusion assay have recently been translated and improved using microfluidics and lab-on-a-chip technologies. These miniaturized cell analysis systems allow for precise spatial and temporal control over a range of dynamic microenvironmental factors including shear stress, biochemical and oxygen gradients to create more reliable in vitro models that resemble the in vivo microenvironment of a wound more closely on a molecular, cellular, and tissue level. The current review provides (a) an overview on the main molecular and cellular processes that take place during wound healing, (b) a brief introduction into conventional in vitro wound healing assays, and (c) a perspective on future cutaneous and vascular wound healing research using microfluidic technology

Tomorrow today: organ-on-a-chip advances towards clinically relevant pharmaceutical and medical in vitro models

The final publication is available via https://doi.org/10.1016/j.copbio.2018.08.009.Organ-on-a-chip technology offers the potential to recapitulate human physiology by keepinghuman cells in a precisely controlled and artificial tissue-like microenvironment. The current andpotential advantages of organ-on-chips over conventional cell cultures systems and animal modelshave captured the attention of scientists, clinicians and policymakers as well as advocacy groupsin the past few years. Recent advances in tissue engineering and stem cell research are also aidingthe development of clinically relevant chip-based organ and diseases models with organ levelphysiology for drug screening, biomedical research and personalized medicine. Here, the latestadvances in organ-on-a-chip technology are reviewed and future clinical applications discussed.Europäische Kommission Horizon 2020Austrian Research Promotion Agency (FFG)EU Joint Programme – Neurodegenerative Disease Research (JPND