| 1. |
- Boelgen, Nimet, et al.
(författare)
-
Cryogelation for preparation of novel biodegradable tissue-engineering scaffolds
- 2007
-
Ingår i: Journal of Biomaterials Science. Polymer Edition. - : Informa UK Limited. - 0920-5063 .- 1568-5624. ; 18:9, s. 1165-1179
-
Tidskriftsartikel (refereegranskat)abstract
- 2-Hydroxyethyl methacrylate-L-lactate (HEMA-LLA) and HEMA-L-lactate-dextran (HEMA-LLA-D) were synthesized. H-1-NMR confirmed the formation of these oligomers and macromers. Cryogels with different pore structures were prepared using different amounts of HEMA, HEMA-LLA and HEMA-LLA-D by a cryogelation technique. SEM micrographs exhibited pore morphologies. Cryogels were highly porous with interconnected pore structures, opaque, spongy and highly elastic. It was possible to compress them to remove the water in the pores and to return to their original form just by immersing them in water in few minutes, which was quite reproducible. Their swelling abilities, compressive strengths and degradation in buffer solutions were found to be related with their structural properties which was controlled by changing the cryogelation recipe.
|
|
| 2. |
- Dainiak, Maria, et al.
(författare)
-
Chromatography of living cells using supermacroporous hydrogels, cryogels
- 2007
-
Ingår i: Advances in Biochemical Engineering, Biotechnology. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0724-6145. ; 106, s. 101-127
-
Tidskriftsartikel (refereegranskat)abstract
- The preparative cell separation is an intrinsic requirement of various diagnostic, biotechnological and biomedical applications. Affinity chromatography is a promising technique for cell separation and is based on the interaction between a cell surface receptor and an immobilised ligand. Most of the currently available matrices have pore size smaller than the size of the cells and are not suitable for cell chromatography due to column clogging. Another problem encountered in chromatographic separation of cells is a difficulty to elute bound cells from affinity surfaces. Application of novel adsorbents, supermacroporous monolithic cryogels, allows overcoming these problems. Cryogels are characterised by highly interconnected large (10-100 mu m) pores, sponge-like morphology and high elasticity. They are easily derivatised with any ligand of choice. Convective migration can be used to transport the cells through the matrix. Target cells bind to affinity ligands, while other cells pass through the cryogel column non-retained and are removed during a washing step. Because of the spongy and elastic nature of the cryogel matrices, the cells are efficiently desorbed by mechanical compression of cryogels, which provides high cell viability and yields. The release of affinity bound cells by mechanical compression of a cryogel monolithic adsorbent is a unique and efficient way of cell detachment. This detachment strategy and the continuous macroporous structure make cryogels very attractive for application in cell separation chromatography.
|
|
| 3. |
- Deraz, Sahar, et al.
(författare)
-
Capture of bacteriocins directly from non-clarified fermentation broth using macroporous monolithic cryogels with phenyl ligands
- 2007
-
Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 40:4, s. 786-793
-
Tidskriftsartikel (refereegranskat)abstract
- The bacteriocin, sakacin P was produced by the bacteriocin-producing strain Lactobacillus sakei CCUG 42687 at 20 degrees C without pH control. The bacteriocin was captured directly from the fermentation broth using macroporous octyl- and phenyl-monolith columns. The large size of the interconnected macropores (up to 100 mu m) in the macroporous monolith allowed for direct fermentation broth processing with no clarification needed. Screening for optimal bacteriocin binding demonstrated that at pH 6.2 about 80% of the bacteriocin activity could be recovered with a purification factor of 150-160 in the cell-free eluate. Capture of bacteriocins from the fermentation broth using macroporous monoliths in the 96-well plate format presents a promising approach for rapid analytical isolation of bacteriocins from numerous samples.
|
|
| 4. |
- Galaev, Igor, et al.
(författare)
-
Effect of matrix elasticity on affinity binding and release of bioparticles. Elution of bound cells by temperature-induced shrinkage of the smart macroporous hydrogel
- 2007
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 23:1, s. 35-40
-
Tidskriftsartikel (refereegranskat)abstract
- The first step of bacterial or viral invasion is affinity and presumably multisite binding of bioparticles to an elastic matrix like a living tissue. We have demonstrated that model bioparticles such as inclusion bodies (spheres of about 1 mu m in size) Escherichia coli cells (rods 1 x 3 mu m), yeast cells (8 mu m spheres), and synthetic microgel particles (0.4 mu m spheres) are binding via different affinity interactions (IgG antibody-protein A, sugar-lectin, and metal ion-chelate) to a macroporous hydrogel (MH) matrix bearing appropriate ligands. The elastic deformation of the MH results in the detachment of affinity bound bioparticles. The particle detachment on elastic deformation is believed to be due to multipoint attachment of the particles to affinity matrix and the disturbance of the distance between affinity ligands when the matrix is deformed. No release of affinity bound protein occurred on elastic deformation. The efficiency of the particle release by the elastic deformation depends on the density of the ligands at the particle surface as well as on the elasticity of the matrix for relatively large particles. The release of the particles occurred irrespectively of whether the deformation was caused by external forces (mechanical deformation) or internal forces (the shrinkage of thermosensitive macroporous poly-N-isopropylacrylamide hydrogel on increase in temperature).
|
|
| 5. |
- Le Noir, Mathieu, et al.
(författare)
-
Macroporous molecularly imprinted polymer/cryogel composite systems for the removal of endocrine disrupting trace contaminants
- 2007
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1154:1-2, s. 158-164
-
Tidskriftsartikel (refereegranskat)abstract
- A new concept for the preparation of selective sorbents with high flow path properties is presented by embedding molecularly imprinted polymers (MIPs) into various macroporous gels (MGs). A MIP was first synthetized with 17β-estradiol (E2) as template for the selective adsorption of this endocrine disrupter. The composite macroporous gel/MIP (MG/MIP) monoliths were then prepared at subzero temperatures. Complete recovery of E2 from a 2 μg/L aqueous solution was achieved using the polyvinyl alcohol (PVA) MG/MIP monoliths whereas only 49-74% was removed with non-imprinted polymers (when no template was used). The PVA MG/MIP monolith columns were operated at almost 10 times higher flow rate (50 mL/min) compared to the MIP columns with operation flow rate of 1-5 mL/min. The possibility for processing the particulate containing wastewater effluents at high flow rates with selectivity on E2 removal, as well as the easy preparation of the monoliths, make the macroporous MG/MIP systems attractive and robust sorbents for the clean up of water from endocrine disrupting trace contaminants.
|
|
| 6. |
- Noppe, W., et al.
(författare)
-
Macroporous monolithic gels, cryogels, with immobilized phages from phage-display library as a new platform for fast development of affinity adsorbent capable of target capture from crude feeds
- 2007
-
Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 131:3, s. 293-299
-
Tidskriftsartikel (refereegranskat)abstract
- Selected phage clones expressing a peptide with high binding affinity for recombinant human lactoferrin or von Willebrand factor (vWF) were covalently coupled to macroporous poly(dimethylacrylamide) monolithic column. Large pore size (10–100 μm) of macroporous poly(dimethylacrylamide) makes it possible to couple long (1 μm) phage particles as ligands without any risk of blocking the monolithic column. The macroporous monolithic columns were successfully used for the direct affinity capture of target proteins from particulate containing feeds like milk containing casein micelles and fat globules (1–10 μm in size) or even whole blood containing blood cells (up to 20 μm in size). The newly developed platform based on selected bacteriophages immobilized within macropores of the monolithic cryogels presents a convenient alternative to antibodies for fast and selective development of the specific adsorbent.
|
|
| 7. |
- Plieva, Fatima, et al.
(författare)
-
Macroporous gels prepared at subzero temperatures as novel materials for chromatography of particulate-containing fluids and cell culture applications
- 2007
-
Ingår i: Journal of Separation Science. - : Wiley. - 1615-9314 .- 1615-9306. ; 30:11, s. 1657-1671
-
Forskningsöversikt (refereegranskat)abstract
- Macroporous gels (MGs) with a broad variety of morphologies are prepared using the cryotropic gelation technique, i.e. gelation at subzero temperatures. These highly elastic hydrophilic materials can be produced from practically any gel-forming system with a broad range of porosity extending from elastic and porous gels with pore sizes up to 1.0 mu m to elastic and sponge-like gels with pore sizes up to 100 mu m. The versatility of the cryogelation technique is demonstrated by use of different chemical reactions (hydrogen bond formation, chemical cross-linking of polymers, free radical polymerization) mainly in an aqueous medium. Appropriate control over solvent crystallization (formation of solvent crystals) and rate of chemical reaction during the cryogelation allows the reproducible preparation of cryogels with tailored properties. Different approaches, such as chemical modification of reactive groups, grafting of the pore surface with an appropriate polymer, or direct copolymerization with functional monomers are used for control of the surface chemistry of MGs. Typically, MGs with pore sizes up to 1.0 mu m are produced in the shape of beads and MGs with pore size up to 100 mu m are prepared as monoliths, discs, and sheets. The difference in porous structure of MGs defines the main applications of these porous materials. Elastic beaded MGs are mostly used as carriers for. cell and enzyme immobilization or for capture of low-molecular weight targets from particulate-containing fluids in expanded-bed mode. However, the elastic and sponge-like MG monoliths with interconnected pores measuring hundreds of gm have been successfully used as monolithic columns for chromatography of particulate-containing fluids (crude cell homogenates, viruses, whole cells, wastewater effluents) and as three-dimensional scaffolds for mammalian cell culture applications.
|
|
