The Experts below are selected from a list of 23871 Experts worldwide ranked by ideXlab platform

Aránzazu Del Campo - One of the best experts on this subject based on the ideXlab platform.

Wei Song - One of the best experts on this subject based on the ideXlab platform.

  • zwitterionically modified alginates mitigate Cellular overgrowth for Cell Encapsulation
    Nature Communications, 2019
    Co-Authors: Alan Chiu, Long-hai Wang, Duo An, Monica Zhong, Alexandra M Smink, Bart J De Haan, Andreas Vegge, Esther Y Chen, Kevin Keane, Wei Song
    Abstract:

    Foreign body reaction (FBR) to implanted biomaterials and medical devices is common and can compromise the function of implants or cause complications. For example, in Cell Encapsulation, Cellular overgrowth (CO) and fibrosis around the Cellular constructs can reduce the mass transfer of oxygen, nutrients and metabolic wastes, undermining Cell function and leading to transplant failure. Therefore, materials that mitigate FBR or CO will have broad applications in biomedicine. Here we report a group of zwitterionic, sulfobetaine (SB) and carboxybetaine (CB) modifications of alginates that reproducibly mitigate the CO of implanted alginate microcapsules in mice, dogs and pigs. Using the modified alginates (SB-alginates), we also demonstrate improved outcome of islet Encapsulation in a chemically-induced diabetic mouse model. These zwitterion-modified alginates may contribute to the development of Cell Encapsulation therapies for type 1 diabetes and other hormone-deficient diseases.

  • designing a retrievable and scalable Cell Encapsulation device for potential treatment of type 1 diabetes
    Proceedings of the National Academy of Sciences of the United States of America, 2018
    Co-Authors: Duo An, Alan Chiu, Wei Song, James A Flanders, Dahua Shou, Yenchun Lu, Lars Groth Grunnet, Louise Winkel, Camilla Ingvorsen, Nicolaj Stroyer Christophersen
    Abstract:

    Cell Encapsulation has been shown to hold promise for effective, long-term treatment of type 1 diabetes (T1D). However, challenges remain for its clinical applications. For example, there is an unmet need for an Encapsulation system that is capable of delivering sufficient Cell mass while still allowing convenient retrieval or replacement. Here, we report a simple Cell Encapsulation design that is readily scalable and conveniently retrievable. The key to this design was to engineer a highly wettable, Ca2+-releasing nanoporous polymer thread that promoted uniform in situ cross-linking and strong adhesion of a thin layer of alginate hydrogel around the thread. The device provided immunoprotection of rat islets in immunocompetent C57BL/6 mice in a short-term (1-mo) study, similar to neat alginate fibers. However, the mechanical property of the device, critical for handling and retrieval, was much more robust than the neat alginate fibers due to the reinforcement of the central thread. It also had facile mass transfer due to the short diffusion distance. We demonstrated the therapeutic potential of the device through the correction of chemically induced diabetes in C57BL/6 mice using rat islets for 3 mo as well as in immunodeficient SCID-Beige mice using human islets for 4 mo. We further showed, as a proof of concept, the scalability and retrievability in dogs. After 1 mo of implantation in dogs, the device could be rapidly retrieved through a minimally invasive laparoscopic procedure. This Encapsulation device may contribute to a Cellular therapy for T1D because of its retrievability and scale-up potential.

  • Designing compartmentalized hydrogel microparticles for Cell Encapsulation and scalable 3D Cell culture
    Journal of materials chemistry. B, 2014
    Co-Authors: Wei Song, Beum Jun Kim, Robert E. Schwartz
    Abstract:

    We describe here designs of compartmentalized hydrogel microparticles with a tunable extraCellular matrix (ECM) support for Cell Encapsulation and scalable 3D Cell culture. The microparticles, rapidly formed by a one-step, multi-fluidic electrostatic spraying technique (>10000 min−1), have a uniform spherical shape, a nearly monodisperse size distribution and controlled compartmentalization. They not only have a high surface area for mass transfer but also offer defined space and essential ECM support for various scalable and efficient 3D Cell culture, co-culture and microtissue production applications.

  • nanofibrous microposts and microwells of controlled shapes and their hybridization with hydrogels for Cell Encapsulation
    ACS Applied Materials & Interfaces, 2014
    Co-Authors: Wei Song, Deri Kao, Guohao Dai, Shuibing Chen, M M
    Abstract:

    A simple, robust, and cost-effective method is developed to fabricate nanofibrous micropatterns particularly microposts and microwells of controlled shapes. The key to this method is the use of an easily micropatternable and intrinsically conductive metal alloy as a template to collect electrospun fibers. The micropatterned alloy allows conformal fiber deposition with high fidelity on its topographical features and in situ formation of diverse, free-standing micropatterned nanofibrous membranes. Interestingly, these membranes can serve as structural frames to form robust hydrogel micropatterns that may otherwise be fragile on their own. These hybrid micropatterns represent a new platform for Cell Encapsulation where the nanofiber frames enhance the mechanical integrity of hydrogel and the micropatterns provide additional surface area for mass transfer and Cell loading.

João F. Mano - One of the best experts on this subject based on the ideXlab platform.

  • Cell Encapsulation in liquified compartments: Protocol optimization and challenges.
    PloS one, 2019
    Co-Authors: Clara R. Correia, Maryam Ghasemzadeh-hasankolaei, João F. Mano
    Abstract:

    Cell Encapsulation is a widely used technique in the field of Tissue Engineering and Regenerative Medicine (TERM). However, for the particular case of liquefied compartmentalised systems, only a limited number of studies have been reported in the literature. We have been exploring a unique Cell Encapsulation system composed by liquefied and multilayered capsules. This system transfigured the concept of 3D scaffolds for TERM, and was already successfully applied for bone and cartilage regeneration. Due to a number of appealing features, we envisage that it can be applied in many other fields, including in advanced therapies or as disease models for drug discovery. In this review, we intend to highlight the advantages of this new system, while discussing the methodology, and sharing the protocol optimization and results. The different liquefied systems for Cell Encapsulation reported in the literature will be also discussed, considering the different Encapsulation matrixes as core templates, the types of membranes, and the core liquefaction treatments.

  • Design Principles and Multifunctionality in Cell Encapsulation Systems for Tissue Regeneration.
    Advanced healthcare materials, 2018
    Co-Authors: Clara R. Correia, Rui L. Reis, João F. Mano
    Abstract:

    Cell Encapsulation systems are being increasingly applied as multifunctional strategies to regenerate tissues. Lessons afforded with Encapsulation systems aiming to treat endocrine diseases seem to be highly valuable for the tissue engineering and regenerative medicine (TERM) systems of today, in which tissue regeneration and biomaterial integration are key components. Innumerous multifunctional systems for Cell compartmentalization are being proposed to meet the specific needs required in the TERM field. Herein is reviewed the variable geometries proposed to produce Cell Encapsulation strategies toward tissue regeneration, including spherical and fiber-shaped systems, and other complex shapes and arrangements that better mimic the highly hierarchical organization of native tissues. The application of such principles in the TERM field brings new possibilities for the development of highly complex systems, which holds tremendous promise for tissue regeneration. The complex systems aim to recreate adequate environmental signals found in native tissue (in particular during the regenerative process) to control the Cellular outcome, and conferring multifunctional properties, namely the incorporation of bioactive molecules and the ability to create smart and adaptative systems in response to different stimuli. The new multifunctional properties of such systems that are being employed to fulfill the requirements of the TERM field are also discussed.

  • Development of a Novel Cell Encapsulation System Based on Natural Origin Polymers for Tissue Engineering Applications
    Journal of Bioactive and Compatible Polymers, 2010
    Co-Authors: Sandra M. Luna, João F. Mano, Manuela E. Gomes, Rui L. Reis
    Abstract:

    Cells microencapsulated in biocompatible semi-permeable polymeric membranes are effective as Cell delivery systems while protecting the host against immune responses. In this study, Cell Encapsulation membranes were prepared based on carrageenan and alginate, two natural cationic polymers. Different formulations/conditions were explored to optimize the microcapsules which were characterized with respect to their morphology, mechanical stability, and cytotoxicity. Spherical-shaped microcapsules were obtained from all the polymeric systems. The iota-carrageenan/sodium alginate microcapsules exhibited the best stability and permeability, and therefore, these were selected for the Cell Encapsulation. These capsules provided an environment that supported Cell proliferation and have the potential for tissue engineering as well as other Cell-based therapy applications.

Sarah C. Heilshorn - One of the best experts on this subject based on the ideXlab platform.

  • Tetrakis(hydroxymethyl) phosphonium chloride as a covalent cross-linking agent for Cell Encapsulation within protein-based hydrogels.
    Biomacromolecules, 2012
    Co-Authors: Cindy Chung, Kyle J. Lampe, Sarah C. Heilshorn
    Abstract:

    Native tissues provide Cells with complex, three-dimensional (3D) environments comprised of hydrated networks of extraCellular matrix proteins and sugars. By mimicking the dimensionality of native tissue while deconstructing the effects of environmental parameters, protein-based hydrogels serve as attractive, in vitro platforms to investigate Cell–matrix interactions. For Cell Encapsulation, the process of hydrogel formation through physical or covalent cross-linking must be mild and Cell compatible. While many chemical cross-linkers are commercially available for hydrogel formation, only a subset are cytocompatible; therefore, the identification of new and reliable cytocompatible cross-linkers allows for greater flexibility of hydrogel design for Cell Encapsulation applications. Here, we introduce tetrakis(hydroxymethyl) phosphonium chloride (THPC) as an inexpensive, amine-reactive, aqueous cross-linker for 3D Cell Encapsulation in protein-based hydrogels. We characterize the THPC-amine reaction by demon...

  • Using Peptide Hetero-assembly to Trigger Physical Gelation and Cell Encapsulation
    MRS Proceedings, 2010
    Co-Authors: Andreina Parisi-amon, Cheryl Wong Po Foo, Ji Seok Lee, Widya Mulyasasmita, Sarah C. Heilshorn
    Abstract:

    AbstractStem Cell transplantation holds tremendous potential for the treatment of various trauma and diseases. However, the therapeutic efficacy is often limited by poor and unpredictable post-transplantation Cell survival. While hydrogels are thought to be ideal scaffolds, the sol-gel phase transitions required for Cell Encapsulation within commercially available biomatrices such as collagen and Matrigel often rely on non-physiological environmental triggers (e.g., pH and temperature shifts), which are detrimental to Cells. To address this limitation, we have designed a novel class of protein biomaterials: Mixing-Induced Two-Component Hydrogels (MITCH) that are recombinantly engineered to undergo gelation by hetero-assembly upon mixing at constant physiological conditions, thereby enabling simple, biocompatible Cell Encapsulation and transplantation protocols. Building upon bio-mimicry and precise molecular-level design principles, the resulting hydrogels have tunable viscoelasticity consistent with simple polymer physics considerations. MITCH are reproducible across Cell-culture systems, supporting growth of human endothelial Cells, rat mesenchymal stem Cells, rat neural stem Cells, and human adipose-derived stem Cells. Additionally, MITCH promote the differentiation of neural progenitors into neuronal phenotypes, which adopt a 3D-branched morphology within the hydrogels.

Julieta I. Paez - One of the best experts on this subject based on the ideXlab platform.

  • Thiol-Methylsulfone-Based Hydrogels for 3D Cell Encapsulation
    ACS applied materials & interfaces, 2020
    Co-Authors: Julieta I. Paez, Aleeza Farrukh, Rocío Valbuena-mendoza, Małgorzata K. Włodarczyk-biegun, Aránzazu Del Campo
    Abstract:

    Thiol-maleimide and thiol-vinylsulfone cross-linked hydrogels are widely used systems in 3D culture models, in spite of presenting uncomfortable reaction kinetics for Cell Encapsulation: too fast (seconds for thiol-maleimide) or too slow (minutes-hours for thiol-vinylsulfone). Here, we introduce the thiol-methylsulfone reaction as alternative cross-linking chemistry for Cell Encapsulation, particularized for PEG-hydrogels. The thiol-methylsulfone reaction occurs at high conversion and at intermediate reaction speed (seconds-minutes) under physiological pH range. These properties allow easy mixing of hydrogel precursors and Cells to render homogeneous Cell-laden gels at comfortable experimental time scales. The resulting hydrogels are cytocompatible and show comparable hydrolytic stability to thiol-vinylsulfone gels. They allow direct bioconjugation of thiol-derivatized ligands and tunable degradation kinetics by cross-linking with degradable peptide sequences. 3D Cell culture of two Cell types, fibroblasts and human umbilical vein endothelial Cells (HUVECs), is demonstrated.