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Bäumler H. Künstliche Sauerstofftransporter können mehr als Sauerstoff liefern. TRANSFUSIONSMEDIZIN 2020. [DOI: 10.1055/a-1119-1796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
ZusammenfassungZum gegenwärtigen Zeitpunkt ist in der EU und den USA kein artifizieller Sauerstofftransporter zugelassen. Hämoglobin-basierte Sauerstoff-Carrier (HBOC) sind bereits seit Jahrzehnten Gegenstand wissenschaftlicher Untersuchungen. Ein wesentliches Hindernis bei der Zulassung war bisher der Anspruch der Entwickler, einen universell einsetzbaren Blutersatz zu produzieren. Die Beschränkung auf eine Indikation scheint erfolgversprechender zu sein. Der Ansatz, nicht nur Sauerstoff von der Lunge zum Gewebe, sondern auch der Abtransport von Kohlendioxid vom Gewebe zur Lunge zu transportieren, der effektiver als mit Erythrozyten durchgeführt werden kann, erscheint besonders attraktiv. Aufgrund vielversprechender präklinischer sowie klinischer Untersuchungen besteht die Hoffnung, dass in absehbarer Zeit auch in der EU künstliche Sauerstofftransporter für therapeutische Zwecke zur Verfügung stehen werden.
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Affiliation(s)
- Hans Bäumler
- Institut für Transfusionsmedizin, Charité – Universitätsmedizin Berlin, Berlin
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Rajamanickam R, Baek S, Gwon K, Hwang Y, Shin K, Tae G. Mechanical stimuli responsive and highly elastic biopolymer/nanoparticle hybrid microcapsules for controlled release. J Mater Chem B 2016; 4:4278-4286. [PMID: 32263409 DOI: 10.1039/c6tb00410e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mechanical stimulus is one of the universally accessible physical ways of triggering the drug release from their carriers. Hollow microcapsules made of polyelectrolyte multilayers by conventional methods are not elastic enough to respond to a large and repetitive mechanical deformation. Here, hybrid hollow capsules comprising alternating layers of inorganic colloidal particles and biopolymers were prepared by the layer-by-layer approach followed by freezing-assisted crosslinking of polymer layers. The size of the capsule was controllable by the size of sacrificial cores. These hybrid capsules were mechanically more stable and recover faster than polyelectrolyte capsules, and could be recovered elastically even after large and repetitive deformation up to 98% relative to their original dimensions. Drugs in a wide range of molecular weight up to 70 kDa Mw could be loaded into the hollow hybrid microcapsules and the release of loaded contents from these hybrid capsules could be controlled through the deformation by applying a weak force such as a finger pressing on them. Mechanical stimuli-responsive delivery of model drugs was demonstrated on a monolayer of these hybrid capsules.
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Affiliation(s)
- Raja Rajamanickam
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, Republic of Korea.
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Kleinberger RM, Burke NAD, Dalnoki-Veress K, Stöver HDH. Systematic study of alginate-based microcapsules by micropipette aspiration and confocal fluorescence microscopy. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:4295-304. [PMID: 23910346 DOI: 10.1016/j.msec.2013.06.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 05/09/2013] [Accepted: 06/19/2013] [Indexed: 12/24/2022]
Abstract
Micropipette aspiration and confocal fluorescence microscopy were used to study the structure and mechanical properties of calcium alginate hydrogel beads (A beads), as well as A beads that were additionally coated with poly-L-lysine (P) and sodium alginate (A) to form, respectively, AP and APA hydrogels. A beads were found to continue curing for up to 500 h during storage in saline, due to residual calcium chloride carried over from the gelling bath. In subsequent saline washes, micropipette aspiration proved to be a sensitive indicator of gel weakening and calcium loss. Aspiration tests were used to compare capsule stiffness before and after citrate extraction of calcium. They showed that the initial gel strength is largely due to the calcium alginate gel cores, while the long term strength is solely due to the poly-L-lysine-alginate polyelectrolyte complex (PEC) shells. Confocal fluorescence microscopy showed that calcium chloride exposure after PLL deposition led to PLL redistribution into the hydrogel bead, resulting in thicker but more diffuse and weaker PEC shells. Adding a final alginate coating to form APA capsules did not significantly change the PEC membrane thickness and stiffness, but did speed the loss of calcium from the bead core.
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Affiliation(s)
- Rachelle M Kleinberger
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4M1,Canada
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Liu C, Long L, Li Z, He B, Wang L, Wang J, Yuan X, Sheng J. Hollow poly(MPC-g-PEG-b-PLA) graft copolymer microcapsule as a potential drug carrier. J Microencapsul 2012; 29:242-9. [DOI: 10.3109/02652048.2011.646328] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Delcea M, Schmidt S, Palankar R, Fernandes PAL, Fery A, Möhwald H, Skirtach AG. Mechanobiology: correlation between mechanical stability of microcapsules studied by AFM and impact of cell-induced stresses. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2010; 6:2858-2862. [PMID: 21086520 DOI: 10.1002/smll.201001478] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Mihaela Delcea
- Max-Planck Institute of Colloids and Interfaces, Interfaces Department, Am Mühlenberg 1, 14476 Potsdam, Germany.
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Kim BS, Choi JW. Polyelectrolyte multilayer microcapsules: Self-assembly and toward biomedical applications. BIOTECHNOL BIOPROC E 2007. [DOI: 10.1007/bf02931052] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Picart C, Senger B, Sengupta K, Dubreuil F, Fery A. Measuring mechanical properties of polyelectrolyte multilayer thin films: Novel methods based on AFM and optical techniques. Colloids Surf A Physicochem Eng Asp 2007. [DOI: 10.1016/j.colsurfa.2007.02.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Georgieva R, Moya SE, Bäumler H, Möhwald H, Donath E. Controlling Ionic Conductivity in Lipid Polyelectrolyte Composite Capsules by Cholesterol. J Phys Chem B 2005; 109:18025-30. [PMID: 16853314 DOI: 10.1021/jp0521407] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of cholesterol on the formation and properties of bilayer lipid membranes deposited on polyelectrolyte multilayered capsules was studied. The permeability of lipid/cholesterol coated capsules for NaCl was derived from osmotic response experiments and ranged from 1.45 x 10(-8) to 2.9 x 10(-8) m.s(-1), which corresponds to a lipid layer conductivity of (0.7-1.4) x 10(-8) S.m(-1). These conductivity values were in good agreement with the value of 0.8 x 10(-8) S.m(-1) obtained by electrorotation and were by 3 orders of magnitude lower than those found earlier for lipid layers on polyelectrolyte capsules in the absence of cholesterol.
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Affiliation(s)
- Radostina Georgieva
- Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Golm/Potsdam, Germany.
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Lebedeva OV, Kim BS, Vasilev K, Vinogradova OI. Salt softening of polyelectrolyte multilayer microcapsules. J Colloid Interface Sci 2005; 284:455-62. [PMID: 15780282 DOI: 10.1016/j.jcis.2004.10.040] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 10/20/2004] [Indexed: 11/28/2022]
Abstract
By using a combination of atomic force and confocal microscopy, we explore the effect of 1:1 electrolyte (NaCl) on the stiffness of polyelectrolyte microcapsules. We study the "hollow" and "filled" (with polystyrene sulfonate) capsules. In both cases the shells are composed of layers of alternating polystyrene sulfonate (PSS) and polyallylamine hydrochloride (PAH). The stiffness of both "hollow" and "filled" capsules was found to be largest in water. It decreases with salt concentration up to approximately 3 mol/L and gets quasi-constant in more concentrated solutions. The "filled" capsules are always stiffer than "hollow." The observed softening correlates with the salt-induced changes in morphology of the multilayer shells detected with the scanning electron microscopy. It is likely that at concentrations below approximately 3 mol/L the multilayer shell is in a "tethered" state, so that the increase in salt concentration leads to a decrease in number of ionic cross-links and, as a result, in the stiffness. In contrast, above the critical concentration of approximately 3 mol/L multilayer shells might be in a new, "melted," state. Here the multilayer structure is still retained, but sufficient amount of ionic cross-links is broken, so that further increase in salt concentration does not change the capsule mechanics. These ideas are consistent with a moderate swelling of multilayers at concentrations below approximately 3 mol/L and significant decrease in their thickness in more concentrated solutions measured with surface plasmon spectroscopy.
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Affiliation(s)
- Olga V Lebedeva
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz 55128, Germany
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Cordeiro AL, Coelho M, Sukhorukov GB, Dubreuil F, Möhwald H. Effect of shear stress on adhering polyelectrolyte capsules. J Colloid Interface Sci 2004; 280:68-75. [PMID: 15476775 DOI: 10.1016/j.jcis.2004.07.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 07/23/2004] [Indexed: 10/26/2022]
Abstract
A parallel plate flow chamber was implemented to study the deformation and adhesion of individual spherical hollow polyelectrolyte multilayered shells adhering to a coated surface. The device provides a well-defined laminar flow allowing the determination of the shear stress to which the capsules are being exposed up to 15 N/m(2). The results of the investigations indicate a strong dependence of the adhesion and mechanical resistance on the capsule size and wall thickness. Thin walled capsules, constituted of 8 polyelectrolyte layers (thickness congruent with 12 nm), are immediately deformed when exposed to flow while thick capsules, constituted of 16 layers (thickness congruent with 24 nm), of equal dimensions are detached from the surface for drag forces below 50 nN. It was observed that adhering capsules exposed to flow undergo an increase in their adhesion area in the direction of flow, resulting in rolling of the capsules. It was also found that the resistance of the capsules decreases after acetone treatment, indicating a weakening of the polyelectrolyte multilayer structure in the presence of this solvent.
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Affiliation(s)
- Ana L Cordeiro
- Max-Planck Institute of Colloids and Interfaces, Germany.
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Silvano D, Krol S, Diaspro A, Cavalleri O, Gliozzi A. Confocal laser scanning microscopy to study formation and properties of polyelectrolyte nanocapsules derived from CdCO3 templates. Microsc Res Tech 2002; 59:536-41. [PMID: 12467031 DOI: 10.1002/jemt.10235] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Three-dimensional confocal laser scanning microscopy (CLSM) was used as an essential investigation method to obtain information about the formation and morphological characteristics of nanocapsules. Nanocapsules are built by layer-by-layer deposition of alternatively charged polyelectrolytes on templates forming nanostructured hollow shells. CLSM is unique in allowing for monitoring of the core dissolution process in real time and for studying nanocapsule functioning in hydrated conditions within a three-dimensional and temporal framework. Since we are also interested in the identification of other possible templates, we briefly report on the use of yeast cells as biocolloidal cores monitored by means of two-photon microscopy. Here we focus our attention on the use of CdCO(3) crystals as template candidates for the preparation of stable capsules. Both cubic and spherical CdCO(3) cores have been produced. Cubic cores exhibit higher monodispersity and smaller size compared to spherical ones. Capsules templated on these cores have a higher surface-to-volume ratio that is valuable for applications related to drug delivery, functional properties of the shells and adsorption of proteins, and other biologically relevant molecules. Microsc. Res. Tech. 59:536-541, 2002.
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Affiliation(s)
- D Silvano
- INFM, Research Unit of Genoa and Department of Physics, University of Genoa, 16146 Genoa, Italy
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Georgieva R, Moya S, Hin M, Mitlöhner R, Donath E, Kiesewetter H, Möhwald H, Bäumler H. Permeation of macromolecules into polyelectrolyte microcapsules. Biomacromolecules 2002; 3:517-24. [PMID: 12005523 DOI: 10.1021/bm010164n] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyelectrolyte microcapsules (PEMCs) have been prepared by coating red blood cells with the polyelectrolytes poly(styrenesulfonate), poly(allylamine hydrochloride), and dextran sulfate applying the layer-by-layer technique with subsequent dissolution of the core. The capsule permeability for human serum albumin (HSA) was studied as a function of the ionic strength and pH by means of confocal microscopy. PEMCs produced with dextran sulfate and poly(allylamine hydrochloride) show a significant increase in permeability for HSA at salt concentrations over 1 mM. For PEMCs prepared with poly(styrenesulfonate) and poly(allylamine hydrochloride) the limiting salt concentration is 5 mM. No pH dependence for permeation was observed. A correlation between the permeation and adsorption of HSA on the PEMC walls was investigated. Finally, a mechanism for the permeability, combining electrostatic interactions, and the presence of pores in the polymer layers is presented confirmed by the considerable increase of permeation of charged molecules in the presence of salt and the permeation of neutral molecules regardless of the ionic strength.
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Affiliation(s)
- R Georgieva
- Institute of Transfusion Medicine, Medical Faculty Charité, Humboldt University of Berlin, Berlin, Germany
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Neu B, Voigt A, Mitlöhner R, Leporatti S, Gao CY, Donath E, Kiesewetter H, Möhwald H, Meiselman HJ, Bäumler H. Biological cells as templates for hollow microcapsules. J Microencapsul 2001; 18:385-95. [PMID: 11308228 DOI: 10.1080/02652040010000398] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Microcapsules in the micrometer size range with walls of nanometer thickness are of both scientific and technological interest, since they can be employed as micro- and nano-containers. Liposomes represent one example, yet their general use is hampered due to limited stability and a low permeability for polar molecules. Microcapsules formed from polyelectrolytes offer some improvement, since they are permeable to small polar molecules and resistant to chemical and physical influences. Both types of closed films are, however, limited by their spherical shape which precludes producing capsules with anisotropic properties. Biological cells possess a wide variety of shapes and sizes, and, thus, using them as templates would allow the production of capsules with a wide range of morphologies. In the present study, human red blood cells (RBC) as well as Escherichia coli bacteria were used; these cells were fixed by glutardialdehyde prior to layer-by-layer (LbL) adsorption of polyelectrolytes. The growth of the layers was verified by electrophoresis and flow cytometry, with morphology investigated by atomic force and electron microscopy; the dissolution process of the biological template was followed by confocal laser scanning microscopy. The resulting microcapsules are exact copies of the biological template, exhibit elastic properties, and have permeabilities which can be controlled by experimental parameters; this method for microcapsule fabrication, thus, offers an important new approach for this area of biotechnology.
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Affiliation(s)
- B Neu
- Institute of Transfusion Medicine, Medical Faculty Charité, Humboldt University of Berlin, Germany
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Literature Alerts. J Microencapsul 2001; 18:411-6. [PMID: 11308230 DOI: 10.1080/02652040010023366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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