Functionalized polyoxometalate microspheres ensure selective adsorption of phosphoproteins and glycoproteins

Polyoxometalate functionalized magnetic metal-organic framework with multi-affinity sites for efficient enrichment of phosphopeptides

The reasonable design of metal-organic framework (MOF)-derived nanomaterial has important meaning in increasing the enrichment efficiency in the study of protein phosphorylation. In this work, a polyoxometalate (POM) functionalized magnetic MOF nanomaterial (Fe3O4@MIL-125-POM) was designed and fabricated. The nanomaterial with multi-affinity sites (unsaturated metal sites and metal oxide clusters) was used for the enrichment of phosphopeptides. Fe3O4@MIL-125-POM had high-efficient enrichment performance towards phosphopeptides (selectivity, a mass ratio of bovine serum albumin/α-casein/β-casein at 5000:1:1; sensitivity, 0.1 fmol; satisfactory repeatability, ten times). Furthermore, Fe3O4@MIL-125-POM was employed to enrich phosphopeptides from non-fat milk digests, saliva, serum, and A549 cell lysate. The enrichment results illustrated the great potential of Fe3O4@MIL-125-POM for efficient identification of low-abundance phosphopeptides.

Amide and Multihydroxyl Complementary Tailored Metal-Organic Framework with Enhanced Glycan Affinity for Efficient Glycoproteomic Analysis

Protein glycosylation is ubiquitous and crucial for regulating biological processes in organisms. Given the heterogeneity and low abundance of glycoproteins, efficient and specific enrichment procedures are required for the mass spectrometry analysis of glycopeptides. Hydrophilic interaction liquid chromatography (HILIC) has emerged as an effective strategy for glycopeptide enrichment. However, the relatively weak hydrophilic affinity restricts the achievement of a satisfactory enrichment performance. Here, we presented a rational design of an amide and multihydroxyl complementary tailored metal-organic framework, denoted as U6N/Pv@Glc, which exhibited ultrahydrophilicity and enhanced glycan affinity. Our results demonstrated a significant increase in glycopeptide coverage after enrichment, accompanied by extremely low detection limits (0.05 fmol μL-1) and high selectivity (IgG/BSA, 1:4000) as evaluated using trypsin-digested standard glycoproteins. A total of 379 glycopeptides and 247 intact glycopeptides (containing a total of 1577 site-specific N-glycans) were identified and characterized within human serum samples from individuals with type 2 diabetes in-depth. Additionally, we extended the application of this material to capture undigested glycoproteins, demonstrating potential compatibility with top-down MS analysis. These results highlight the promising potential of this novel material for comprehensive glycoproteomic analysis of every potential aspect.

Immobilized horseradish peroxidase on boric acid modified polyoxometalate molecularly imprinted polymer for biocatalytic degradation of phenol in wastewater: Optimized immobilization, degradation and toxicity assessment

The degradation of phenol from wastewater is crucial for environmental protection. Biological enzymes, such as horseradish peroxidase (HRP), have shown great potential in the degradation of phenol. In this research, we prepared a hollow CuO/Cu2O octahedron adsorbent with a carambola matrix shape through the hydrothermal method. The surface of the adsorbent was modified by silane emulsion self-assembly, where 3-aminophenyl boric acid (APBA) and polyoxometalate (PW9) were combined with silanization reagents and grafted onto the surface. The adsorbent was then molecularly imprinted with dopamine to obtain boric acid modified polyoxometalate molecularly imprinted polymer (Cu@B@PW9@MIPs). This adsorbent was used to immobilize HRP, which served as a biological enzyme catalyst from horseradish. The adsorbent was characterized, and its synthetic conditions, experimental conditions, selectivity, reproducibility, and reusability were evaluated. The maximum adsorption amount of HRP under optimized conditions was 159.1 mg g-1, as determined using high-performance liquid chromatography (HPLC). At pH 7.0, the immobilized enzyme showed a high efficiency of up to 90.0% in removing phenol, after 20 min of reaction with 25 mmol L-1 H2O2 and 0.20 mg mL-1 Cu@B@PW9@HRP. Growth tests of aquatic plants confirmed that the adsorbent reduced harm. Gas chromatography-mass spectrometry (GC-MS) tests revealed that the degraded phenol solution contained about fifteen phenol derivatives intermediates. This adsorbent has the potential to become a promising biological enzyme catalyst for dephenolization.

Hierarchical Mesoporous Metal-Organic Frameworks with Boric Acid Sites on the Inner Surface of Small Mesopores for the Extraction of Nucleotides in Human Plasma Samples

In this work, a boronate affinity-functionalized hierarchical mesoporous metal-organic framework adsorbent with boronate sites only in the small mesopore has been structured based on UiO-66@Fe₃O₄. The introduction of large mesopores in the adsorbent can promote the diffusion of small cis-diol-containing compounds (cis-diols) into small mesopore channels, and the removal of the adsorption sites on the external surface of materials and in large mesopores can enhance the size-exclusion effect of the adsorbent. In addition, the adsorbent has faster adsorption kinetics and excellent selectivity to small cis-diols. Finally, a magnetic dispersive solid-phase extraction coupled with high-performance liquid chromatography was established for the enrichment and detection of nucleotides in plasma. Four nucleotides achieve the recoveries from 93.25 to 118.79%, the limits of detection from 0.35 to 1.26 ng·mL^-1, and the intra-day and inter-day relative standard deviations of less than 10.2%. In conclusion, this method can be directly used for the detection of small cis-diol targets in complex biological samples without protein precipitation prior to the extraction.

A nanoscale polymolybdate builded by two hexavacant Keggin-type fragments via a novel {Ca6P6O38} cluster with β-sheet conformation modulation ability

A novel sandwich-type phosphomolybdate based on two hexavacant Keggin-type building block [PMo6O28]15– incorporating a novel hexagonal calcium phosphorus oxygen cluster {Ca6P6O38} was successfully synthesized. It can modulate the β-sheet-rich misfolding...