Derivatives of PSAs are synthesized, in which a reducing and/or non-reducing end terminal sialic acid unit is transformed into a N-hydroxysuccinimide (NHS) group. The derivatives may be reacted with substrates, for instance substrates containing amine or hydrazine groups, to form non-cross-linked/crosslinked polysialylated compounds. The substrates may, for instance, be therapeutically useful drugs, peptides or proteins or drug delivery systems.

Derivatives of PSAs are synthesised, in which a reducing and/or non-reducing end terminal sialic acid unit is transformed into a N-hydroxysuccinimide (NHS) group. The derivatives may be reacted with substrates, for instance substrates containing amine or hydrazine groups, to form non-cross-linked/crosslinked polysialylated compounds. The substrates may, for instance, be therapeutically useful drugs, peptides or proteins or drug delivery systems.

Derivatives of PSAs are synthesised, in which a reducing and/or non-reducing end terminal sialic acid unit is transformed into a N-hydroxysuccinimide (NHS) group. The derivatives may be reacted with substrates, for instance substrates containing amine or hydrazine groups, to form non-cross-linked/crosslinked polysialylated compounds. The substrates may, for instance, be therapeutically useful drugs, peptides or proteins or drug delivery systems.

The present disclosure relates to, inter alia, a green technology for crosslinking protein molecules for various uses, where the protein molecules can be contained in protein fibers such as, but not limited to, human hair, animal fibers, and mixtures thereof. In one aspect, the present disclosure relates to a crosslinking agent comprising an oxidized sugar having at least two aldehyde groups. In another aspect, the present disclosure relates to a method of crosslinking protein fibers. This method involves providing the aforementioned crosslinking agent and infiltrating a plurality of non-crosslinked protein fibers with the crosslinking agent under conditions effective to cause protein molecules contained in the non-crosslinked protein fibers to become crosslinked, thereby yielding a population of crosslinked protein fibers.

The present disclosure relates to, inter alia, a green technology for crosslinking protein molecules for various uses, where the protein molecules can be contained in protein fibers such as, but not limited to, human hair, animal fibers, and mixtures thereof. In one aspect, the present disclosure relates to a crosslinking agent comprising an oxidized sugar having at least two aldehyde groups. In another aspect, the present disclosure relates to a method of crosslinking protein fibers. This method involves providing the aforementioned crosslinking agent and infiltrating a plurality of non-crosslinked protein fibers with the crosslinking agent under conditions effective to cause protein molecules contained in the non-crosslinked protein fibers to become crosslinked, thereby yielding a population of crosslinked protein fibers.

Disclosed is a method of crosslinking hair or other keratin fibers by (i) providing a crosslinking agent comprising an oxidized sugar having at least two aldehyde groups; and (ii) infiltrating a plurality of non-crosslinked hair or other keratin fibers with the crosslinking agent under conditions effective to cause protein molecules contained in the non-crosslinked hair or other keratin fibers to become crosslinked, thereby yielding a population of crosslinked hair or other keratin fibers. The protein molecules include amine groups that react with the aldehyde groups of the oxidized sugar to yield the crosslinked hair or other keratin fibers. Also disclosed are formulations for crosslinking hair or other keratin fibers and methods of using the formulations to treat human hair to maintain a desired three dimensional structure. This formulation includes a crosslinking agent having a plurality of oxidized sugars having at least two aldehyde groups or mixture thereof.