Biocompatible in situ hydrogel

#This disclosure generally relates to a material that can form a hydrogel upon injection into a space within the body, and applications thereof.

#A hydrogel is a material consisting of water-filled networks of cross-linked polymers. One of the most important features of this type of material is its hydrophilic nature, which enables many of its varieties to be compatible with the body. Moreover, the physical and chemical properties, which include, but are not limited to, mechanical properties, volume change behavior, drug controlled release behavior, functionalization of chemical moieties, and gel-body interactions, can be well controlled in a hydrogel system. Therefore, a hydrogel is favorable in many kinds of biomedical applications, including, but not limited to, tissue engineering, tissue augmentation, tissue filling, drug delivery, and cell delivery.

#However, a hydrogel is a viscoelastic solid, and due to its limited ability to deform, it is difficult to place into the body without surgically opening the body. A special type of hydrogel, sometimes referred to as “in situ” hydrogel, is a material that can change from a viscoelastic liquid to viscoelastic solid (or “sol-gel transition”) when the gel is injected into the body. This property enables the material to be placed in the body by a minimally invasive manner, e.g., by an injection. This additional advantage, together with the other properties stated above, make in situ hydrogels attractive candidates in many biomedical applications. Nevertheless, the development of this type of hydrogel is challenging. One of the most challenging spaces to form an in situ hydrogel is the endoluminal space for endoluminal therapy. “Endoluminal” is an adjective describing a space inside the lumen of a body. A lumen refers to a tube-like structure inside the body. Examples of lumens in the body include, but are not limited to, blood vessels, lymphatic vessels, respiratory tract, digestive tract, fallopian tubes, and ductus deferens. One type of endoluminal therapy is to use an external material to fill up certain spaces inside the lumen. Examples of this type therapy include lumen embolization and ligature. The medical conditions needed for this type of therapy may be of various kinds. One particular example of a medical condition is vascular abnormality.

#FIG. 1 shows a compression test on different hydrogel composed of physical crosslinkink alone, chemical crosslinking alone, or a combination of both types of crosslinks.

#FIG. 2 shows a hydrogel of the present invention extruded out from a vessel-mimicking tube.

#FIG. 3 shows a hydrogel of the present invention in the coronary artery of a porcine heart after injection.

#Aspects of the present invention are directed to compositions and related methods and kits that can form in situ hydrogels in physiological environments indicative of an animal body, such as, but not limited to, the human body.

#Several aspects of the invention are described below, with reference to examples for illustrative purposes only. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the invention. One having ordinary skill in the relevant art, however, will readily recognize that the invention can be practiced without one or more of the specific details or practiced with other methods, protocols, reagents, etc. The present invention is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts, steps or events are required to implement a methodology in accordance with the present invention. Many of the techniques and procedures described, or referenced herein, are well understood and commonly employed using conventional methodology by those skilled in the art.

#Prior to setting forth the invention in detail, it may be helpful to the understanding thereof to define several terms, and these are accordingly set forth in the next section, below. Unless otherwise defined, all terms of art, notations and other scientific terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the art to which this invention pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or as otherwise defined herein.