Provided are a combination of cross-linked hyaluronic acids comprising: a cross-linked hyaluronic acid having an elasticity of about 50 to about 200 Pa and a viscosity of about 20 to about 100 Pa, and a cross-linked hyaluronic acid having an elasticity of about 400 to about 800 Pa and a viscosity of about 40 to about 100 Pa, and a method for preparing the same.

A nanoglue is formed with one or more bioadhesive polymers, one or more dendrimers, and optionally one or more therapeutic, prophylactic, or diagnostic agents. The bioadhesive polymers and dendrimers are modified with functional groups to permit crosslinking upon one or more stimuli, e.g., ultraviolet irradiation, and form hydrogel in situ at tissue sites. In the repair of corneal wounds, the nanoglue leads to improved rate of healing with less scarring and less inflammation, compared to non-treated cornea or ones treated with sutures. Therapeutic agents can be covalently conjugated to the precursor components and be delivered to specific eye compartments, providing a more efficacious treatment formulation of ocular disorders than delivering drugs in their free forms. Methods of making and using the hydrogel and hydrogel precursor compositions are also provided.

An eyedrop composition, and methods of making and using the same, may include one or more hydrogel forming polymer having an intrinsic viscosity [η] of at least 3 dL/g in the composition, wherein a concentration C.sub.T of such hydrogel forming polymer in the composition is at most about 5 mg/mL.

A method is provided for producing a composition comprising chitosan and water, comprising dissolving chitosan powder in an ionic liquid, to prepare a first composition comprising chitosan and ionic liquid; and contacting the first composition with water under conditions sufficient to solvent-exchange all or substantially all of the ionic liquid with water; to form a composition comprising chitosan and water. Compositions produced thereby and methods of using the compositions are provided.

The invention relates to a polymer-clay composite material comprising clay nanoparticles and a polymer, and wherein (a) the polymer comprises phosphate and/or phosphonate ligands; or (b) the polymer-clay composite further comprises linker molecules comprising a phosphate or phosphonate ligand, wherein the linker molecules are arranged to be anchored to the polymer. The invention further relates to organoclays, BMP-clay composite material. Uses, treatments, and manufacturer of the material are also provided.

Methods of forming cross-linked polysaccharides are disclosed in which one or more polysaccharides are dissolved in solution, gelled, modified to have a desired concentration, and subsequently irradiated. The irradiation of the gel crosslinks the polysaccharide(s) present. The disclosed techniques may be applied to various polysaccharides, including but not limited to agarose and/or hyaluronic acid.

Disclosed is a preparation method for polylactic acid grafted chitosan nanowhiskers, and belongs to the technical field of materials. The preparation method of the disclosure is that after lactide, a catalyst and chitosan are uniformly mixed, polymerization grafting is performed to prepare PLA-g-CS, and then the PLA-g-CS is dispersed into an alkali liquor to obtain nanowhiskers by a repeated freezing/unfreezing method, with no solvent used in a polymerization grafting process. The method has advantages that the nanowhiskers can be prepared from the PLA-g-CS without a good solvent, and the whole reaction is efficient, clean, and environmentally friendly.

The present invention concerns a method for producing a hydrogel comprising the following steps in succession: a first step (i) of providing at least one powder of an anionic polymer (A) and at least one chitosan powder (B) comprising amine functions (—NH.sub.2); a second step (ii) consisting in dry mixing at least the powders (A) and (B) from the first step in order to form a mixture of powders; a third step (iii) of suspending the mixture of powders obtained from the second step in an aqueous medium having a pH that can enable the anionic polymer (A) to be dissolved without dissolving the chitosan (B); a fourth step (iv) of adding an acid to the suspension obtained from the third step in order to form the hydrogel; or the third (iii) and fourth (iv) steps are replaced by a mixing fifth step (v), comprising mixing an acidified aqueous medium including at least one compound (C) comprising at least one unit of a hexose or a unit derived from a hexose, and/or at least one phosphate of said compound (C), with said mixture comprising at least the powders (A) and (B) obtained from the second step (ii).

A new hydrogel made of crosslinked glycosaminoglycans, particularly crosslinked hyaluronic acid, chondroitin or chondroitin sulfate, having reversible linkages using boronic acid or boroxole derivatives leading to new benefits. Glycosaminoglycans that are crosslinked via an alkoxyboronate ester anion formed between a diol portion of a diol-functional moiety grafted to a first glycosaminoglycan and a boronate hemiester grafted to a second glycosaminoglycan.

A preparation method of a cross-linked sodium hyaluronate gel is disclosed, which including: preparing an alkaline aqueous solution of hyaluronic acid: formulating a sodium hyaluronate alkali liquor with the concentration of 10-30% g/ml; and carrying out a cross-linking reaction: the cross-linking agent used in the cross-linking reaction being divinyl sulfone or 1,4-butanediol diglycidyl ether, the cross-linking reaction being carried out in an alkaline aqueous solution of hyaluronic acid, the reaction temperature of the cross-linking reaction being 20-40° C., the time of the cross-linking reaction being 4-8 h, and the like. The method of this invention has many advantages, such as easily available raw materials, mild reaction conditions, high cross-linking efficiency, simple process and post-treatment, and easy operation. The obtained cross-linked sodium hyaluronate has a three-dimensional network structure by the crosslinking reaction with good mechanical properties, and can be used as a good drug carrier and a tissue engineering scaffold material.