Nitrogen-Doped Graphene Quantum Dots Anchored on Hollow Zeolitic Imidazolate Framework-8 Colloidosomes for Fluorescence Detection of Glucose

Abstract

Hollow-structured nanomaterials, featuring a porous crystalline structure and hollow interior, are conducive to achieving a compartmentalized architecture comprising diverse functional entities. In this study, we have constructed a novel fluorescent enzyme nanocomposite derived from the nanosized hollow ZIF-8 (H-ZIF-8) colloidosomes via a diffusion strategy. Insights into the underlying mechanisms revealed that the diffusion process was driven by mesopore properties and electrostatic interactions. It has also been demonstrated that the molecular sieving property of the colloidosome shell induced an exceptional compartmentalized structure, where nitrogendoped graphene quantum dots (N-GQDs) were anchored onto the outer surface of the nanosized H-ZIF-8 colloidosomes, whereas glucose oxidase (GOx) was homogeneously encapsulated in the entire cavity. The resultant nanocomposite inherited the mesopore properties of the colloidosome exoskeleton, catalytic ability of GOx, and fluorescence properties of N-GQDs. In particular, the porous properties of the nanosized H-ZIF-8 colloidosomes favored enrichment to target analytes, whereas the compartmentalized GOx and N-GQDs served as a "promoter" (initiate the biochemical reaction) and "signal unit" (intuitive observation) in the glucose probing system, respectively. Furthermore, anchoring N-GQDs onto the outer surface of the nanosized H-ZIF-8 resulted in tailoring of the fluorescence property of the nanocomposite. In the part of glucose sensing, the proposed fluorescence nanosensor could well quantify glucose within a range of 10 to 100 μM with a lower limit of detection of 5.4 μM. This proposed strategy presents opportunities to engineer novel metal−organic framework-based multifunctional nanocomposites and create new applications by combining their unique functions.

A sensitive lateral flow test strip sensor for visual detection of acid red 18 in food using bicentric-emission carbon dots

“…The decrease in the average fluorescence lifetime of N-CDs (from 2.27 to 2.20 ns) provides evidence of an energy transfer process transpiring between N-CDs and AR18. 36,37…”

“…The decrease in the average fluorescence lifetime of N-CDs (from 2.27 to 2.20 ns) provides evidence of an energy transfer process transpiring between N-CDs and AR18. 36,37 Regarding the modest quenching of the blue emission at 425 nm, it becomes evident that there is no significant overlap between the UV-vis absorption spectrum of AR18 and the blue emission spectrum of N-CDs, except for a slight overlap resulting from the trailing peak at 541 nm under shorter excitation wavelengths. The weak absorption of AR18 in relationship to the trailing emission in the blue channel disrupts the equilibrium of electron distribution, diminishing the electron density in blue channel of N-CDs under consistent excitation (at 377 nm).…”

Antibacterial Mesoporous Silica Granules Containing a Stable N-Halamine Moiety

“…Mesoporous silica which has a large specific surface area with highly ordered pores and a narrow pore size distribution has been widely used in the fields of separation, catalysis, drug delivery, and nanosensors, etc. − Due to its large surface area, porous structure, very good thermal stability, and hydrophilicity, silica has the potential to be prepared as a water treatment and antimicrobial material. There have been some reports about N-halamine-modified mesoporous silica antimicrobial materials. , The obtained mesoporous silica containing N-halamine moieties has good antibacterial activities.…”