Hydrogels that undergo volumetric expansion in response to changes in their environment and their methods of manufacture and use
A hydrogel material that permits cellular ingrowth and has controlled rate of expansion optimized for delivery through a microcatheter or catheter without the need for a non-aqueous solvent or a coating has not been developed. Accordingly, there remains a need in the art for the development of such a hydrogel useable as tissue compatible implants.
Cruise and Constant of MicroVention, Inc, California, developed a hydrogel sufficiently porous to permit cellular ingrowth for implants. The hydrogels are prepared by forming a liquid reaction mixture that contains a) monomer(s) and/or polymer(s) at least portion(s) of which are sensitive to environmental changes (e.g., changes in pH or temperature), b) a crosslinker and c) a polymerization initiator. If desired, a porosigen, (e.g., sodium chloride, ice crystals, and sucrose) is included. Porosity is formed by the subsequent removal of the porosigen from the resultant solid hydrogel (e.g, by repeated washing). The controlled rate of expansion is developed by adding ethylenically unsaturated monomers with ionizable functional groups such as amines or carboxylic acids, In addition a stimulus-expandable hydrogel material of the present invention may be rendered radiopaque radiopaque particles (e.g., tantalum, gold, platinum, etc.) into the liquid reaction mixture. These hydrogels can be used for the treatment of aneurysms, fistulae, arterio-venous malformations and vessel occlusions. [
Delivery system for bone growth promoting material
Fischer of Ultradent Products, Inc., Utah, developed a delivery system that includes a bone growth promoting material encapsulated within a water absorptive gelatinizable covering is used to promote bone growth in order to repair a bone defect and/or strengthen a weakened bone region. The delivery system may be shaped and sized in order to fit within a bleeding wound (e.g. one that is formed in the gingiva when a tooth is extracted). The covering may be formed of a gelatinizable gauze that forms a gel-like material when moistened with water. The delivery system is contained within a moisture resistant package prior to use. Alternatively, the delivery system comprises a bone growth promoting material and thickening agent contained within a syringe that, upon adding water, form a viscous gel or stiff putty. A polymerizable resin may be placed over the bone growth composition after placement on a bone to form a protective barrier layer. (RDC 10/8/2012)
Methods and compositions for treating tissue using silk proteins
Hossainy et al of Abbott Cardiovascular Systems Inc. California, Compositions developed a self-reinforcing composite biomatrix with three components, a first functionalized polymer, a second functionalized polymer and silk protein. This material can also include a cell type and a growth factor. This material is used to heal damage from myocardial infarctions. (RDC 6/19/2012)
High density fibrous polymers suitable for implant
Ringeisen and Wattengel of Kensey Nash, Delaware, applied malleable, biodegradable, fibrous compositions to a tissue site in order to promote or facilitate new tissue growth. The material is formed from a slurry of natural or synthetic polymer fibers and at least one suspension fluid by applying a force, e.g., centrifugal, to form the material. (RDC 6/8/2012)
Composite materials comprising supported porous gels containing metal-affinity ligands
Childs et al of Natrix Separations, Canada, developed a porous composite filled with a macroporous cross-linked gel. The composite material is suitable, for example, for separation of substances, for example by filtration or adsorption, including chromatography, for use as a support in synthesis or for use as a support for cell growth. (RDC 6/7/2012)
Flexible membrane valve for cell culture vessel
Cattadoris, Martin and Tanner of Corning Incorporated, New York, developed an assembly for culturing cells including a housing defining a reservoir for containing cell culture media and an opening in fluid communication with the reservoir. The cell culture assembly further includes a filter valve assembly configured to sealingly engage the opening. The filter valve assembly includes a flexible membrane, a contiguous side wall, an end wall, and a microbial filter. The end wall has an opening and extends across one end of the side wall to form a major cavity within the side wall and the end wall. The flexible membrane has a slit spanning the membrane and is disposable within the major cavity such that the membrane sealingly divides the major cavity into (i) a chamber formed between the end wall and the membrane and (ii) a minor cavity formed by the membrane and a portion of the side wall. The minor cavity is in fluid communication with the reservoir. The slit is biased in a closed position to prevent fluid from passing from the minor cavity into the chamber and is configured to open to allow gas to pass from the minor cavity into the chamber when the pressure differential across the membrane is above a threshold. The filter is disposed between the membrane and the opening such that air flowing through the opening in the end wall into the chamber passes through the filter. (RDC 5/22/2012)
Roger D. Corneliussen
Maro Polymer Links
Tel: 610 363 9920
Fax: 610 363 9921
Copyright 2012 by Roger D. Corneliussen.
No part of this transmission is to be duplicated in any manner or forwarded by electronic mail without the express written permission of Roger D. Corneliussen
** Date of latest addition; date of first entry is 5/22/2012.