Sequentially epitaxial growth multi-guest encapsulation strategy in MOF-on-MOF platform: Biogenic amine detection and systematic white light adjustment

MOF-on-MOF heterostructures possess multiple advantages inherited from various single-component metal -organic frameworks (MOFs). Here, we prepare a three-dimensional (3D) anionic fluorescence MOF {[In-5(dpda)(4)(H2O)(4)].H3O.3H(2)O}n (In-dpda) (H4dpda = 3-(3',5'-dicarboxyphenyl)pyridine-2,6-dicarboxylic acid) with open 1D square channels. Due to the high lattice match (> 97.8 %), classical ZIF-8 with powerful guest encapsulation ability controllably grows on the fluorescent core In-dpda to assemble a ZIF-8-on-In-dpda heterostructure through the sequentially epitaxial growth strategy. In addition, a smart ratiometric fluorescence sensor F-10c subset of & nbsp;& nbsp;ZIF-8-on-In-dpda is further constructed by synchronously encapsulating the fluorescein (F) during the epitaxial growth of ZIF-8 nanoparticles and presents high sensitivity to a biogenic amine with a low limit of detection of 4.7 nM at the 10 cycles assembly. The dual detection modes of both ratiometric fluorescent intensity and CIE chromaticity show a potential application in food safety monitoring. Meanwhile, multi-guest molecules F and rhodamine B are sequentially encapsulated in the guests & SUB; ZIF-8-on-In-dpda to achieve diverse luminescent colors including white light emission. This work presents a sequentially epitaxial growth strategy based on the lattice matching principle to assemble MOF-on-MOF platforms for multiple applications.

Automated summary

The study demonstrates the assembly of ZIF-8-on-In-dpda heterostructures on a fluorescent MOF core through epitaxial growth strategy, leading to the construction of a highly sensitive fluorescence sensor with potential applications in food safety monitoring. Additionally, diverse luminescent colors including white light emission are achieved by sequentially encapsulating multiple guest molecules in the ZIF-8-on-In-dpda composite.