A low molecular weight Zr(IV) metallogel for protein delivery

With an exceptional portfolio of properties such as high water content and cross-linked nature, hydrogels can provide an ideal and compatible environment not only to encapsulate but also to control the delivery of biological therapeutics. However, uncontrollable degradation, release and especially swelling impose limitations on our ability to engineer these gels. Herein a zirconium metallogel is proposed that utilizes zirconyl tetramers as the metal component in conjunction with a nucleic acid (adenine). The variable gel-formation temperature as a simple step of gel formation allows the tuning of gel formation and properties by controlling the adenine-nucleobase interactions. Reconstitution, entrapment, degradation, cytotoxicity, and release of bovine serum albumin (BSA) as a negatively charged macromolecular therapeutic agent were investigated. The controllable and sustained release of BSA, offers a route to new tailorable protein delivery applications.