The present invention relates to a process of preparing a rubber-like material containing a protein immobilized therein, as well as a corresponding rubber-like material, the process comprising the steps of (a) mixing a protein, a branched polymer such as trimethylolpropane ethoxylate and a linear polymer such as poly(ethylene oxide) in an aqueous solution to form a gel, and (b) drying the gel to obtain a rubber-like material containing the protein immobilized therein, wherein the branched polymer comprises at least three polymeric branches bound to a central branching unit. The rubber-like material allows the immobilization and stabilization of a wide range of different proteins, including luminescent proteins as well as enzymes, and can particularly advantageously be used as down-converting material for light-emitting diodes (LEDs), for diagnostic applications, and in bioreactors.

The invention provides for novel thermo-responsive polymers and compositions comprising the same. In some embodiments, the polymers are water soluble, pH-degradable and have tunable lower critical solution temperatures. Other aspects of the invention include micelles and gels comprising the thermo-responsive polymers and derivatives thereof, as well as methods of delivering therapeutic agents comprising administering a biodegradable gel or micelle comprising a polyacetal compound cross-linked with a linker.

A multi-arm polyethylene glycol derivative having a narrow molecular weight distribution represented by the formula (1): ##STR00001##
wherein, L represents a group selected from a linear or branched alkylene, arylene, or cycloalkylene group having two or more carbon atoms and combinations thereof, which may have an ether bond in a chain; X represents a dehydroxylation residue of a linear sugar alcohol having 5 or 7 carbon atoms; m is the number of polyethylene glycol chains bonded to X and represents 4 or 6; n is the average addition molar number of oxyethylene groups and represents an integer of 3 to 600; Y represents a single bond or an alkylene group as further defined herein; and Z represents a chemically reactive functional group.

The present invention discloses a Y-type discrete polyethylene glycol derivative and a preparation method thereof, which has the advantages of determined molecular weights and the number of chain segments, and can avoid the defect of heterogeneity of a PEG derivative, meanwhile the preparation method has simple steps, mild conditions, without need for strictly anhydrous environment or performing protection and deprotection steps. In addition, the Y-type discrete polyethylene glycol derivative of the present invention may increase the water solubility of the discrete polyethylene glycol, and solve the problem of insufficient water solubility of the discrete polyethylene glycol-modified insoluble drug caused by an increase of the loading capacity.

Disclosed are multi-arm polyethylene glycol derivatives having structure of formula I or formula VI. Compared with straight chain polyethylene glycol, multi-arm polyethylene glycol has a plurality of terminal groups, thus has a plurality of introducing points of functional groups and can support a plurality of reactive terminal groups, thereby enabling multi-arm polyethylene glycol to have more flexibility and wider range of application. ##STR00001##

Hydrogels that degrade under appropriate conditions of pH and temperature by virtue of crosslinking compounds that cleave through an elimination reaction are described. The hydrogels may be used for delivery of various agents, such as pharmaceuticals.

The invention provides compound of the general formula:

##STR00001##

in which each X independently represents a polymer chain; n represents an integer greater than 1; Q represents a linker; Y represents an amide group; and Z represents either CH.(CH.sub.2L).sub.2 or C(CH.sub.2L)(CH.sub.2), in which each L independently represents a leaving group. The compounds are useful reagents for the conjugation of polymers to proteins, the resulting conjugates being novel and also forming part of the invention.

A self-branching polyetherimide comprising a first repeating unit derived from polymerization of the aromatic dianhydride and a first diamine, wherein the first diamine comprises a carboxyl-substituted C.sub.6-24 aromatic hydrocarbon group; and optionally, a second repeating unit derived from polymerization of an aromatic dianhydride and a second diamine, wherein the second diamine comprises a C.sub.1-30 divalent hydrocarbon group, optionally comprising 1 to 4 heteroatoms, wherein the self-branching polyetherimide is end-capped with phthalic anhydride.

The invention provides a novel approach to hydrogels with predictable degradation/gelling kinetics, which is useful for many biomedical applications where appropriate gelling kinetics and the timely disintegration of the hydrogel (e.g., drug delivery, guided tissue regeneration) is required. Precisely controlling hydrogel degradation over a broad range in a predictable manner is achieved via a simple but versatile hydrogel platform that allows formulation of hydrogels with predictable disintegration time from within 2 days to >250 days yet comparable macroscopic physical properties.

The present invention provides adhesive hydrogels that negatively swell at physiological temperature. By combining mussel-mimetic chemistry and the thermosensitive nature of poly(ethylene oxide)-poly(propylene oxide) copolymers, novel materials were designed that are suitable as medical sealants and adhesives.