Metal–organic frameworks (MOFs) have dramatically changed the fundamentals of drug delivery, catalysis, and gas storage as a result of their porous geometry, controlled architecture, and ease of postsynthetic modification. However, the biomedical applications of MOFs still remain a less explored area due to the constraints associated with handling, utilizing, and site-specific delivery. The major drawbacks associated with the synthesis of nano-MOFs are related to the lack of control over particle size and inhomogeneous dispersion during doping. Therefore, a smart strategy for the in situ growth of a nano-metal–organic framework (nMOF) has been devised to incorporate it into a biocompatible polyacrylamide/starch hydrogel (PSH) composite for therapeutic applications. In this study, the post-treatment of zinc metal ion cross-linked PSH with the ligand solution generated the nZIF-8@PAM/starch composites (nZIF-8, nano-zeolitic imidazolate framework-8). The ZIF-8 nanocrystals thus formed have been found to be evenly dispersed throughout the composites. This newly designed nanoarchitectonics of an MOF hydrogel was found to be self-adhesive, which also exhibited improved mechanical strength, a viscoelastic nature, and a pH-responsive behavior. Taking advantage of these properties, it has been utilized as a sustained-release drug delivery platform for a potential photosensitizer drug (Rose Bengal). The drug was initially diffused into the in situ hydrogel, and then the entire scaffold was analyzed for its potential in photodynamic therapy against bacterial strains such as E. coli and B. megaterium. The Rose Bengal loaded nano-MOF hydrogel composite exhibited remarkable IC50 values within the range of 7.37 ± 0.04 and 0.51 ± 0.05 μg/mL for E. coli and B. megaterium. Further, reactive oxygen species (ROS) directed antimicrobial potential was validated using a fluorescence-based assay. This smart in situ nanoarchitectonics hydrogel platform can also serve as a potential biomaterial for topical treatment including wound healing, lesions, and melanoma.

Surface reducibility engineering is one of the vital tools to enhance the catalytic activity of materials.

No abstract

This work compares the capacity of generating the surface oxygen vacancies over SrTiO₃, BaTiO₃ and the mixed Sr_0.5Ba_0.5TiO₃. This aspect is elucidated by significantly different chemical states of the elements on the surface of the three materials. Along with the fundamental materials aspect, CO oxidation studies complement the highest surface reducibility of the Sr_0.5Ba_0.5TiO₃ catalyst. With detailed adsorption-desorption studies, we report that the A-site cation substitution renders a better surface-reducibility induced catalytic activity for CO oxidation.

This work compares the capacity of generating the surface oxygen vacancies over SrTiO₃, BaTiO₃ and the mixed Sr_0.5Ba_0.5TiO₃. This aspect is elucidated by significantly different chemical states of the elements on the surface of the three materials. Along with the fundamental materials aspect, CO oxidation studies complement the highest surface reducibility of the Sr_0.5Ba_0.5TiO₃ catalyst. With detailed adsorption-desorption studies, we report that the A-site cation substitution renders a better surface-reducibility induced catalytic activity for CO oxidation.