| 1. |
- Aronsson, Christopher, et al.
(författare)
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Dynamic peptide-folding mediated biofunctionalization and modulation of hydrogels for 4D bioprinting
- 2020
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Ingår i: Biofabrication. - : Institute of Physics Publishing (IOPP). - 1758-5082 .- 1758-5090. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels are used in a wide range of biomedical applications, including three-dimensional (3D) cell culture, cell therapy and bioprinting. To enable processing using advanced additive fabrication techniques and to mimic the dynamic nature of the extracellular matrix (ECM), the properties of the hydrogels must be possible to tailor and change over time with high precision. The design of hydrogels that are both structurally and functionally dynamic, while providing necessary mechanical support is challenging using conventional synthesis techniques. Here, we show a modular and 3D printable hydrogel system that combines a robust but tunable covalent bioorthogonal cross-linking strategy with specific peptide-folding mediated interactions for dynamic modulation of cross-linking and functionalization. The hyaluronan-based hydrogels were covalently cross-linked by strain-promoted alkyne-azide cycloaddition using multi-arm poly(ethylene glycol). In addition, a de novo designed helix-loop-helix peptide was conjugated to the hyaluronan backbone to enable specific peptide-folding modulation of cross-linking density and kinetics, and hydrogel functionality. An array of complementary peptides with different functionalities was developed and used as a toolbox for supramolecular tuning of cell-hydrogel interactions and for controlling enzyme-mediated biomineralization processes. The modular peptide system enabled dynamic modifications of the properties of 3D printed structures, demonstrating a novel route for design of more sophisticated bioinks for four-dimensional bioprinting. © 2020 The Author(s). Published by IOP Publishing Ltd.
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| 2. |
- Bengtsson, Katarina, 1985-, et al.
(författare)
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A clip-on electroosmotic pump for oscillating flow in microfluidic cell culture devices
- 2018
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Ingår i: Microfluidics and Nanofluidics. - : Springer Berlin/Heidelberg. - 1613-4982 .- 1613-4990. ; 22:3
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in microfluidic devices put a high demand on small, robust and reliable pumps suitable for high-throughput applications. Here we demonstrate a compact, low-cost, directly attachable (clip-on) electroosmotic pump that couples with standard Luer connectors on a microfluidic device. The pump is easy to make and consists of a porous polycarbonate membrane and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) electrodes. The soft electrode and membrane materials make it possible to incorporate the pump into a standard syringe filter holder, which in turn can be attached to commercial chips. The pump is less than half the size of the microscope slide used for many commercial lab-on-a-chip devices, meaning that these pumps can be used to control fluid flow in individual reactors in highly parallelized chemistry and biology experiments. Flow rates at various electric current and device dimensions are reported. We demonstrate the feasibility and safety of the pump for biological experiments by exposing endothelial cells to oscillating shear stress (up to 5 dyn/cm2) and by controlling the movement of both micro- and macroparticles, generating steady or oscillatory flow rates up to ± 400 μL/min.
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| 3. |
- Christoffersson, Jonas, 1986-, et al.
(författare)
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A Cardiac Cell Outgrowth Assay for Evaluating Drug Compounds Using a Cardiac Spheroid-on-a-Chip Device
- 2018
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Ingår i: Bioengineering. - : MDPI AG. - 2306-5354. ; 5:2, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) models with cells arranged in clusters or spheroids have emerged as valuable tools to improve physiological relevance in drug screening. One of the challenges with cells cultured in 3D, especially for high-throughput applications, is to quickly and non-invasively assess the cellular state in vitro. In this article, we show that the number of cells growing out from human induced pluripotent stem cell (hiPSC)-derived cardiac spheroids can be quantified to serve as an indicator of a drug’s effect on spheroids captured in a microfluidic device. Combining this spheroid-on-a-chip with confocal high content imaging reveals easily accessible, quantitative outgrowth data. We found that effects on outgrowing cell numbers correlate to the concentrations of relevant pharmacological compounds and could thus serve as a practical readout to monitor drug effects. Here, we demonstrate the potential of this semi-high-throughput “cardiac cell outgrowth assay” with six compounds at three concentrations applied to spheroids for 48 h. The image-based readout complements end-point assays or may be used as a non-invasive assay for quality control during long-term culture.
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| 4. |
- Christoffersson, Jonas, 1986-, et al.
(författare)
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Fabrication of modular hyaluronan-PEG hydrogels to support 3D cultures of hepatocytes in a perfused liver-on-a-chip device
- 2019
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Ingår i: Biofabrication. - : Institute of Physics (IOP). - 1758-5082 .- 1758-5090. ; 11:1, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Liver cell culture models are attractive in both tissue engineering and for development of assays for drug toxicology research. To retain liver specific cell functions, the use of adequate cell types and culture conditions, such as a 3D orientation of the cells and a proper supply of nutrients and oxygen, are critical. In this article, we show how extracellular matrix mimetic hydrogels can support hepatocyte viability and functionality in a perfused liver-on-a-chip device. A modular hydrogel system based on hyaluronan and poly(ethylene glycol) (HA-PEG), modified with cyclooctyne moieties for bioorthogonal strain-promoted alkyne-azide 1, 3-dipolar cycloaddition (SPAAC), was developed, characterized, and compared for cell compatibility to hydrogels based on agarose and alginate. Hepatoma cells (HepG2) formed spheroids with viable cells in all hydrogels with the highest expression of albumin and urea in alginate hydrogels. By including an excess of cyclooctyne in the HA backbone, azide-modified cell adhesion motifs (linear and cyclic RGD peptides) could be introduced in order to enhance viability and functionality of human induced pluripotent stem cell derived hepatocytes (hiPS-HEPs). In the HA-PEG hydrogels modified with cyclic RGD peptides hiPS-HEPs migrated and grew in 3D and showed an increased viability and higher albumin production compared to when cultured in the other hydrogels. This flexible SPAAC crosslinked hydrogel system enabled fabrication of perfused 3D cell culture of hiPS-HEPs and is a promising material for further development and optimization of liver-on-a-chip devices.
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| 5. |
- Christoffersson, Jonas, 1986-
(författare)
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Organs-on-chips for the pharmaceutical development process : design perspectives and implementations
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Organs-on-chips are dynamic cell culture devices created with the intention to mimic organ function in vitro. Their purpose is to assess the toxicity and efficacy of drugs and, as early as possible in the pharmaceutical development process, predict the outcome of clinical trials. The aim of this thesis is to explain and discuss these cell culture devices from a design perspective and to experimentally exemplify some of the specific functions that characterize organs-on-chips.The cells in our body reside in complex environments with chemical and mechanical cues that affect their function and purpose. Such a complex environment is difficult to recreate in the laboratory and has therefore been overlooked in favor of more simple models, i.e. static twodimensional (2D) cell cultures. Numerous recent reports have shown cell culture systems that can resemble the cell’s natural habitat and enhance cell functionality and thereby potentially provide results that better reflects animal and human trials. The way these organs-on-chips improve in vitro cell culture assays is to include e.g. a three-dimensional cell architecture (3D), mechanical stimuli, gradients of oxygen or nutrients, or by combining several relevant cell types that affect each other in close proximity.The research conducted for this thesis shows how cells in 3D spheroids or in 3D hydrogels can be cultured in perfused microbioreactors. Furthermore, a pump based on electroosmosis, and a method for an objective conceptual design process, is introduced to the field of organs-on-chips.
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| 6. |
- Nawaz, Muhammad, et al.
(författare)
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Lipid Nanoparticles Deliver the Therapeutic VEGFA mRNA In Vitro and In Vivo and Transform Extracellular Vesicles for Their Functional Extensions
- 2023
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Ingår i: Advanced Science. - : John Wiley & Sons. - 2198-3844. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- Lipid nanoparticles (LNPs) are currently used to transport functional mRNAs, such as COVID-19 mRNA vaccines. The delivery of angiogenic molecules, such as therapeutic VEGF-A mRNA, to ischemic tissues for producing new blood vessels is an emerging strategy for the treatment of cardiovascular diseases. Here, the authors deliver VEGF-A mRNA via LNPs and study stoichiometric quantification of their uptake kinetics and how the transport of exogenous LNP-mRNAs between cells is functionally extended by cells’ own vehicles called extracellular vesicles (EVs). The results show that cellular uptake of LNPs and their mRNA molecules occurs quickly, and that the translation of exogenously delivered mRNA begins immediately. Following the VEGF-A mRNA delivery to cells via LNPs, a fraction of internalized VEGF-A mRNA is secreted via EVs. The overexpressed VEGF-A mRNA is detected in EVs secreted from three different cell types. Additionally, RNA-Seq analysis reveals that as cells’ response to LNP-VEGF-A mRNA treatment, several overexpressed proangiogenic transcripts are packaged into EVs. EVs are further deployed to deliver VEGF-A mRNA in vitro and in vivo. Upon equal amount of VEGF-A mRNA delivery via three EV types or LNPs in vitro, EVs from cardiac progenitor cells are the most efficient in promoting angiogenesis per amount of VEGF-A protein produced. Intravenous administration of luciferase mRNA shows that EVs could distribute translatable mRNA to different organs with the highest amounts of luciferase detected in the liver. Direct injections of VEGF-A mRNA (via EVs or LNPs) into mice heart result in locally produced VEGF-A protein without spillover to liver and circulation. In addition, EVs from cardiac progenitor cells cause minimal production of inflammatory cytokines in cardiac tissue compared with all other treatment types. Collectively, the data demonstrate that LNPs transform EVs as functional extensions to distribute therapeutic mRNA between cells, where EVs deliver this mRNA differently than LNPs.
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