Multiscale requirements for bioencapsulation in medicine and biotechnology

Vos, Paul De; Bučko, Marek; Gemeiner, Peter; Navrátil, Marián; Švitel, Juraj; Faas, Marijke M.; Strand, Berit Løkensgard; Skjåk‐Bræk, Gudmund; Mørch, Ýrr; Vikartovská, Alica; Lacı́k, Igor; Kolláriková, Gabriela; Orive, Gorka; Poncelet, D.; Pedraz, José Luís; Ansorge‐Schumacher, Marion B.

doi:10.1016/j.biomaterials.2009.01.014

Cited by 184 publications

(143 citation statements)

References 154 publications

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“…The development of encapsulation techniques, including the PEC capsules, has progressed towards a precise and targeted characterisation of the morphology, physicochemical properties of capsules, biocompatibility and their changes over time, using the latest techniques [11,12] for applications in biotechnology and medicine. Additionally, there is also an increased effort to optimise immobilization by predicting and modelling the bioengineering parameters of potential industrial processes [13].…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization

et al. 2017

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A novel immobilization matrix for the entrapment of viable whole-cell Baeyer-Villiger monooxygenase was developed. Viable recombinant Escherichia coli cells overexpressing cyclohexanone monooxygenase were entrapped in polyelectrolyte complex beads prepared by a two-step reaction of oppositely-charged polymers including highly defined cellulose sulphate. Immobilized cells exhibited higher operational stability than free cells during 10 repeated cycles of Baeyer-Villiger biooxidations of rac-bicyclo[3.2.0]hept-2-en-6-one to the corresponding lactones (1R,5S)-3-oxabicyclo-[3.3.0]oct-6-en-3-one and (1S,5R)-2-oxabicyclo-[3.3.0]oct-6-en-3-one. The morphology of polyelectrolyte complex beads was characterised by environmental scanning electron microscopy; the spatial distribution of polymers in the beads and cell viability were examined using confocal laser scanning microscopy, and the texture was characterised by the mechanical resistance measurements.

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Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization

et al. 2017

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“…Isolated islets can be encapsulated within permeable hydrogels such as alginate to provide an immunoprotective barrier that may preclude pharmacological immunosuppression. 8,9 However, encapsulation devices introduce a transport barrier between the host and graft tissues and inherently limit oxygen supply, compromising graft function and cell viability, 10 problems that scale with device wall thickness. 11,12 Typically grafts are implanted in subcutaneous 13 or intraperitoneal 14 sites where partial pressures of oxygen (pO 2 ) are approximately 60 and 40 mm Hg, respectively, which is lower than that of arterial blood (>80 mm Hg).…”

Section: Introductionmentioning

confidence: 99%

Method measuring oxygen tension and transport within subcutaneous devices

et al. 2014

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Abstract. Cellular therapies hold promise to replace the implantation of whole organs in the treatment of disease. For most cell types, in vivo viability depends on oxygen delivery to avoid the toxic effects of hypoxia. A promising approach is the in situ vascularization of implantable devices which can mediate hypoxia and improve both the lifetime and utility of implanted cells and tissues. Although mathematical models and bulk measurements of oxygenation in surrounding tissue have been used to estimate oxygenation within devices, such estimates are insufficient in determining if supplied oxygen is sufficient for the entire thickness of the implanted cells and tissues. We have developed a technique in which oxygen-sensitive microparticles (OSMs) are incorporated into the volume of subcutaneously implantable devices. Oxygen partial pressure within these devices can be measured directly in vivo by an optical probe placed on the skin surface. As validation, OSMs have been incorporated into alginate beads, commonly used as immunoisolation devices to encapsulate pancreatic islet cells. Alginate beads were implanted into the subcutaneous space of Sprague-Dawley rats. Oxygen transport through beads was characterized from dynamic OSM signals in response to changes in inhaled oxygen. Changes in oxygen dynamics over days demonstrate the utility of our technology. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…In order to protect grafts against this reactivity, encapsulation methods have been developed for implants in extra-hepatic sites [5,6]. Alginate microcapsules have been the longest in use and technical advances have been made in improving their biocompatibility, stability and permeability, and in producing variants with selected properties [7][8][9]. They have allowed successful allotransplants of islet tissue in the peritoneal cavity of rodents [10][11][12] and of large animals [13,14], often without the need for continuous immune suppression [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Sustained function of alginate-encapsulated human islet cell implants in the peritoneal cavity of mice leading to a pilot study in a type 1 diabetic patient

Jacobs‐Tulleneers‐Thevissen¹,

Marie²,

Ling³

et al. 2013

Diabetologia

198

184

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Aims/hypothesis Alginate-encapsulated human islet cell grafts have not been able to correct diabetes in humans, whereas free grafts have. This study examined in immunodeficient mice whether alginate-encapsulated graft function was inferior to that of free grafts of the same size and composition. Methods Cultured human islet cells were equally distributed over free and alginate-encapsulated grafts before implantation in, respectively, the kidney capsule and the peritoneal cavity of non-obese diabetic mice with severe combined immunodeficiency and alloxan-induced diabetes. Implants were followed for in vivo function and retrieved for analysis of cellular composition (all) and insulin secretory responsiveness (capsules). Results Free implants with low beta cell purity (19±1%) were non-functional and underwent 90% beta cell loss. At medium purity (50±1%), they were functional at post-transplant week 1, evolving to normoglycaemia (4/8) or to C-peptide negativity (4/8) depending on the degree of beta cell-specific losses. Encapsulated implants immediately and sustainably corrected diabetes, irrespective of beta cell purity (16/16). Most capsules were retrievable as single units, enriched in endocrine cells that exhibited rapid secretory responses to glucose and glucagon. Single capsules with similar properties were also retrieved from a type 1 diabetic recipient at post-transplant month 3. However, the vast majority were clustered and contained debris, explaining the poor rise in plasma C-peptide. Conclusions/interpretation In immunodeficient mice, i.p. implanted alginate-encapsulated human islet cells exhibited a better outcome than free implants under the kidney capsule. They did not show primary non-function at low beta cell purity and avoided beta cell-specific losses by rapidly establishing normoglycaemia. Retrieved capsules presented secretory responses to glucose, which was also observed in a type 1 diabetic recipient.

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Multiscale requirements for bioencapsulation in medicine and biotechnology

Cited by 184 publications

References 154 publications

Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization

Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization

Method measuring oxygen tension and transport within subcutaneous devices

Sustained function of alginate-encapsulated human islet cell implants in the peritoneal cavity of mice leading to a pilot study in a type 1 diabetic patient

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