Why Design Matters: From Decorated Metal Oxide Clusters to Functional Metal–Organic Frameworks

Linear, Planar, Orbicular, and Macrocyclic Multinuclear Zinc (Meth)acrylate Complexes

Zinc carboxylate complexes are widely utilized as artificial models of metalloenzymes and as secondary building units of PCPs/MOFs. However, the relationship between the structure of the monodentate carboxylato ligand and the molecular arrangement of multinuclear zinc carboxylate complexes is not fully understood because of the coordination flexibility of the Zn ion and carboxylato ligands. Herein, we report the structural analysis of a series of complexes derived from zinc (meth)acrylate which has a linear infinite chain structure. The molecular structure of μ4-oxido-bridged tetranuclear complexes [Zn4(μ4-O)(OCOR)6] revealed a distorted Zn4O core. Crystallization of zinc acrylate under aqueous conditions afforded a μ3-hydroxido-containing pentanuclear complex [Zn5(μ3-OH)2(OCOR)8] as the repeating unit of an infinite sheet-like structure in the solid state. It was also obtained by the hydrolysis of the μ4-oxido-bridged tetranuclear complex. In sharp contrast, the methacrylate analog retained the methacrylato ligands under aqueous crystallization conditions to form a macrocyclic dodecanuclear complex with methacrylato as the sole ligand.

Emerging trends in the nanomedicine applications of functionalized magnetic nanoparticles as novel therapies for acute and chronic diseases

High-quality point-of-care is critical for timely decision of disease diagnosis and healthcare management. In this regard, biosensors have revolutionized the field of rapid testing and screening, however, are confounded by several technical challenges including material cost, half-life, stability, site-specific targeting, analytes specificity, and detection sensitivity that affect the overall diagnostic potential and therapeutic profile. Despite their advances in point-of-care testing, very few classical biosensors have proven effective and commercially viable in situations of healthcare emergency including the recent COVID-19 pandemic. To overcome these challenges functionalized magnetic nanoparticles (MNPs) have emerged as key players in advancing the biomedical and healthcare sector with promising applications during the ongoing healthcare crises. This critical review focus on understanding recent developments in theranostic applications of functionalized magnetic nanoparticles (MNPs). Given the profound global economic and health burden, we discuss the therapeutic impact of functionalized MNPs in acute and chronic diseases like small RNA therapeutics, vascular diseases, neurological disorders, and cancer, as well as for COVID-19 testing. Lastly, we culminate with a futuristic perspective on the scope of this field and provide an insight into the emerging opportunities whose impact is anticipated to disrupt the healthcare industry.

Aggregation-induced emission enhancement of gold nanoclusters in metal-organic frameworks for highly sensitive fluorescent detection of bilirubin

A fluorescence analysis method based on gold nanocluster (AuNC) and metal-organic framework (MOF) composite materials (AuNCs@ZIF-8) was established for highly sensitive detection of bilirubin (BR). First, AuNCs@ZIF-8 was successfully obtained by co-precipitation and displayed an aggregation-induced emission enhancement by the confinement effect of the MOFs (i.e., ZIF-8). The product showed approximately 7.0 times enhancement in the quantum yield and longer fluorescence lifetime from 2.29 μs to 11.51 μs compared with AuNCs. When BR combined with the metal node Zn2+ of ZIF-8, the skeleton of the composite was destroyed, leading to a great decrease in the fluorescence intensity by the transformation of the AuNCs from the aggregated state to dispersed state. The linear range for the detection of BR was 0.1-5.0 μM, with the limit of detection (LOD) of 0.07 μM (S/N = 3). The AuNCs@ZIF-8 exhibited a selective response toward BR within 5 min and detected BR in human serum. The long-wavelength emission by AuNCs avoided the interference of the complex biomatrix background fluorescence, indicating their great application prospects for clinical diagnosis.