Beyond Pristine Metal-Organic Frameworks: Preparation of Hollow MOFs and Their Composites for Catalysis, Sensing, and Adsorption Removal Applications

Advances in Nanomaterials and Composites Based on Mesoporous Materials as Antimicrobial Agents: Relevant Applications in Human Health

Nanotechnology has emerged as a cornerstone in contemporary research, marked by the advent of advanced technologies aimed at nanoengineering materials with diverse applications, particularly to address challenges in human health. Among these challenges, antimicrobial resistance (AMR) has risen as a significant and pressing threat to public health, creating obstacles in preventing and treating persistent diseases. Despite efforts in recent decades to combat AMR, global trends indicate an ongoing and concerning increase in AMR. The primary contributors to the escalation of AMR are the misuse and overuse of various antimicrobial agents in healthcare settings. This has led to severe consequences not only in terms of compromised treatment outcomes but also in terms of substantial financial burdens. The economic impact of AMR is reflected in skyrocketing healthcare costs attributed to heightened hospital admissions and increased drug usage. To address this critical issue, it is imperative to implement effective strategies for antimicrobial therapies. This comprehensive review will explore the latest scientific breakthroughs within the metal-organic frameworks and the use of mesoporous metallic oxide derivates as antimicrobial agents. We will explore their biomedical applications in human health, shedding light on promising avenues for combating AMR. Finally, we will conclude the current state of research and offer perspectives on the future development of these nanomaterials in the ongoing battle against AMR.

Triple microenvironment modulation of zeolite imidazolate framework (ZIF) nanocages for boosting dopamine electrocatalysis

Multiple microenvironmental modulation of zeolite imidazole framework-8 (ZIF-8) is expected to solve the long-term intractable problem of low sensitivity in electrochemical sensing. Herein, the metal phthalocyanines with different central ions (PcM, M = Fe, Co, Ni and Cu) were introduced into ZIF-8 by in-situ synthesis method. Then, the hollow composite nanomaterials, HZIF-8/PcFe and HZIF-8@PcFe (HZIF-8, i.e., hollow ZIF-8) with different TA (tannic acid) coating thicknesses (∼11 nm and ∼33 nm) were successfully fabricated by carefully designed polyphenol-mediated modulation (PMM) strategy. Next, the HZIF-8@PcFe electrochemical sensor was constructed for selective and sensitive analysis by selecting dopamine (DA) as the analyte. The TA coating (superhydrophilic state), PcFe (redox properties) and hollow MOF cavity (faster mass transfer) was used as the triple microenvironment modulation of ZIF-8 to enhance the electrocatalytic performance. Under the optimum conditions (pH = 8.0), the linear correlations of 0.3 to 200 μmol/L was obtained for the peak current response, with a detection limit of 0.1 μmol/L (S/N = 3, i.e., Signal/Noise = 3). Meanwhile, the HZIF-8@PcFe electrochemical sensor exhibited excellent interference selectivity, reproducibility and stability, which enabled it to detect low abundance DA in real samples. And the F-test (homogeneity test of variance) and t-test (student's t test) statistical analyses were employed to enhance the accuracy of the actual samples' detection. This work will enlighten researchers working in the field of porous framework composites and open up new paths for the development of hollow MOFs hybrid materials in electrochemical sensing.

Controllable assembly of hollow interpenetrated zeolite imidazole framework nanocomposite for dopamine charge collection

The synergistic armor-etching (SAE) approach was proposed using natural organic weak acid (tannic acid, i.e., TA) for the controllable assembly of hollow and interpenetrated HZIF-8@MWCNTs hybrid nanomaterial (ZIF-8, zeolitic imidazolate framework-8; MWCNTs, multi-walled carbon nanotubes), which exhibited highly ordered crystal structure and unique morphological characteristics. The SAE strategy not only can rapidly etch solid ZIF- material into a hollow structure (~ 10 min), but also form the TA shell (~ 33 nm) on its surface. Then, the HZIF-8@MWCNTs electrochemical sensor was constructed for selective and sensitive detection of the target molecule (dopamine, DA). A sequence of studies indicated that the fabricated TA coating was capable of promoting the spread of DA into the reactive centers of hollow MOF and MWCNTs, which exhibited outstanding electroanalytical characteristics through the synergistic effect. The DPV oxidation peak of DA was strongest at 50 mV vs. Ag/AgCl reference electrode. Under the optimal conditions, there are two linear dynamic ranges of current response of 0.01 ~ 10 and 10 ~ 550 µmol L- 1 with a detection limit of 0.003 µmol·L- 1 (S/N = 3). Simultaneously, the HZIF-8@MWCNTs electrochemical sensor could detect low levels of DA in real products. The recoveries of the actual sample tests were between 98.2% and 102%, and the relative standard deviation (R.S.D.) of all studies was less than 3.0%. The statistical analyses (F-test and t-test) were employed to demonstrate the accuracy of method developed. This work will enlighten researchers operating in the domain of MOFs composites, accelerating the advancement of electrochemical sensing on the basis of hollow MOFs materials.

Chiral metal-organic frameworks and their composites as stationary phases for liquid chromatography chiral separation: A minireview

Chiral metal organic frameworks (CMOFs) are a kind of crystal porous framework material that has attracted increasing attention due to the customizable combination of metal nodes and organic ligands. In particular, the highly ordered crystal structure and rich adjustable chiral structure make it a promising material for developing new chiral separation material systems. In this review, the progress of CMOFs and their different types of composites used as chiral stationary phases (CSPs) in liquid chromatography for enantioseparation are discussed. The characteristics of CMOFs and their composites are summarized, aiming to provide new ideas for the development of CMOFs with better performance and further promote the application of CMOFs materials in enantioselective high-performance liquid chromatography (HPLC).