Tryptophan-Modulated Nanoscale Metal–Organic Framework for Coordinated Loading of Biomolecules for Cascade Production of Reactive Oxygen and Nitrogen Species

Abstract

Owing to the high surface area and porosity, metal− organic frameworks (MOFs) could be utilized as both nanocarriers of biopharmaceuticals and nanoreactors to organize cascade biological reactions with great potential in cancer treatment. However, nanoscale MOFs suitable for biomedical applications rely on harsh preparation conditions. Here, we utilized tryptophan to modulate the morphology and optical properties of zeolitic imidazolate framework-8 (ZIF-8) as nanocarrier to efficiently encapsulate the enzyme and mRNA. Under room temperature in an aqueous solution, tryptophan would coordinate with zinc ions to form ZIF-8:Trp with a decreased size from the μm range to sub-200 nm. In addition, cargo release could be monitored in real time via fluorescence red-shift effects. Besides being used as nanocarriers of biomolecules, ZIF-8:Trp could also be utilized as nanoreactors to induce cascade reactions to produce reactive oxygen and nitrogen species. Overall, this nanosized ZIF-8:Trp could provide a new strategy for preparation of cascade bioreactions and provide new insight for gas therapy.

Understanding and controlling the nucleation and growth of metal–organic frameworks

“…Non-planar substrates, which are surfaces that are more complex and have three-dimensional structures, provide a larger surface area for the MOFs to grow on, leading to faster formation and higher yields. [112][113][114] Examples of non-planar substrates include foams, 115 fibers, 116 nanowires, 117 proteins, 7,114,118,119 and porous metals. 120,121 A study by Ogata et al used bovine serum albumin as a non-planar substrate to lower the interfacial energy barrier and tune the crystal morphology and structure.…”

Porous Molybdenum Nitride Nanosphere as Carrier-Free and Efficient Nitric Oxide Donor for Synergistic Nitric Oxide and Chemo/Sonodynamic Therapy

“…It is known that ROS can combine with NO to produce peroxynitrite (• ONOO − ). 44,45 Here, dihydrorhodamine 123 (DHR) is used as a specific indicator that can be oxidized by •ONOO − to make green fluorescence. As displayed in Figure 3I, the distinct emission peak at 526 nm indicates •ONOO − generation under US irradiation.…”

“…Therefore, US also can be used to improve NO production, which further facilitates the controllability and the practical application in biomedicine. It is known that ROS can combine with NO to produce peroxynitrite (·ONOO – ). , Here, dihydrorhodamine 123 (DHR) is used as a specific indicator that can be oxidized by ·ONOO – to make green fluorescence. As displayed in Figure I, the distinct emission peak at 526 nm indicates ·ONOO – generation under US irradiation.…”

Bioactive glass doped with zinc-based metal–organic frameworks (Zn/MOF) nanoparticles for antibiotic delivery applications

“…Moreover, for BG/Zn MOF sample, the interaction of the prepared nanoparticles with the cell walls of fungi or bacteria causes leakage of Zn 2+ ions. Consequently, this process leads to the formation of reactive oxygen species, which in turn disrupts the integrity of the microbial cell wall, ultimately resulting in its demise [54][55][56][57].…”