Ion-Mediated Gelation of Aqueous Suspensions of Cellulose Nanocrystals.

Nanofibrillar hydrogels are an important class of biomaterials with applications as catalytic scaffolds, artificial extracellular matrixes, coatings, and drug delivery materials. In the present work, we report the results of a comprehensive study of nanofibrillar hydrogels formed by cellulose nanocrystals (CNCs) in the presence of cations with various charge numbers and ionic radii. We examined sol-gel transitions in aqueous CNC suspensions and the rheological and structural properties of the CNC hydrogels.

Microfluidic generation of composite biopolymer microgels with tunable compositions and mechanical properties.

To develop an understanding of the nature of complex, spatiotemporal interactions between cells and the extracellular matrix (ECM), artificial ECMs formed from hydrogels with a particular spectrum of properties are being developed at a rapid pace. We report the microfluidic generation of small, monodisperse composite agarose-gelatin hydrogel modules (microgel particles) that can be used for cell encapsulation and can serve as instructive cellular microenvironments. The agarose component of the microgels gelled under reduced temperature, while gelatin modified with phenolic hydroxyl groups underwent peroxidase-catalyzed gelation.

Effect of pendant group structure on the hydrolytic stability of polyaspartamide polymers under physiological conditions.

We describe the synthesis of metal chelating polymers based on polyaspartamide and polyglutamide backbones as carriers for (111)In in radioimmunoconjugates. These polymers [PAsp(DTPA), PGlu(DTPA)] have a biotin end group and diethylenetriaminepentaacetic acid (DTPA) chelators attached to the primary amines of the diethylenetriamine (DET) pendant groups of biotin-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} [PAsp(DET)] and of biotin-poly{N'-[N-(2-aminoethyl)-2-aminoethyl]glutamide} [PGlu(DET)]. Like Asn-containing proteins and polypeptides, polyaspartamides undergo uncatalyzed degradation under model physiological conditions (10 mM phosphate buffer, pH 7.