Ion-Induced Gelation of Alginate in the Presence of Alanine Hydroximate Metallacrowns of Sr(II), Са(II), and La(III)

The possibility of using water-soluble heteronuclear metallamacrocyclic complexes of Sr(II)–Cu(II), Ca(II)–Cu(II), and La(III)–Cu(II) as crosslinking agents for alginate hydrogels has been investigated for the first time. The possibility of ion-induced crosslinking of alginate with metallacrown cations has been experimentally demonstrated. Alginate hydrogel microspheres have been prepared via extrusion, using the metallacrowns as crosslinking agents. The degree of cross-linking of the hydrogels depends on the nature of the central element of the metallacrown. In terms of their crosslinking ability, the considered metallacrowns (MC(M)) are arranged in the following series: MC(La) > MC(Sr) > MC(Ca).