Linker Ratio-Dependent Physicochemical Properties of ZIF-8 Encapsulated Mini Protein 20 Mimicking Uricase

Abstract

Despite a growing interest in zeolitic imidazolate framework-8 (ZIF-8), notably for their potential as a host for various bio- and molecules, including peptides, the critical factors affecting their physicochemical properties and encapsulation efficiency are relatively unknown, limiting their widespread use. Herein, mini protein 20 (mp20), biomolecule mimicking uricase was used as a model to be hosted within ZIF-8 (mp20@ZIF-8) biocomposites. ZIF-8 were synthesized over a range of molar ratio of Zn to 2-methylimidazole(2-HmIm). By systematically exploring the impacts of various linker ratios, we found that a Zn to 2-HmIm ratio of 1 : 4 offers the highest encapsulation efficiency and thermal stability, making it particularly suitable for applications where these properties are critical. The 1 : 8 ratio, on the other hand, makes biocomposites with the most crystallized and a well-balanced combination of particle size and surface area, which are advantageous for applications requiring high structural integrity and surface interaction. This approach not only advances our understanding of protein encapsulation in MOFs but also provides new insights into how the linker-to-metal ratio can be optimized for different applications. Subsequent studies could expand upon these findings by implementing the enhanced biocomposites in practical applications, examining the encapsulation of biomolecules, or assessing the durability the long-term stability and functionality of these materials in various conditions.