Metal-organic framework-mediated synthesis of hierarchical layered double hydroxide for high-efficiency enrichment of phosphopeptides

Recent Progress and Applications of Advanced Nanomaterials in Solid-Phase Extraction

Sample preparation maintains a key bottleneck in the whole analytical procedure. Solid-phase sorbents (SPSs) have garnered increasing attention in sample preparation research due to their crucial roles in achieving high clean-up and enrichment efficiency in the analysis of trace targets present in complex matrices. Novel nanoscale materials with improved characteristics have garnered considerable interest across different scientific disciplines due to the limited capabilities of traditional bulk-scale materials. The purpose of this review is to offer a thorough summary of the latest developments and uses of SPSs in preparing samples for chromatographic analysis, focusing on the years 2020-2024. The techniques for preparing SPSs are examined, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), carbon nanoparticles (CNPs), molecularly imprinted polymers (MIPs), and metallic nanomaterials (MNs). Examining the pros and cons of different extraction methods, including solid-phase extraction (SPE), magnetic SPE (MSPE), flow-based SPE (FBA-SPE), solid-phase microextraction (SPME), stir-bar sorptive extraction (SBSE), and dispersive SPE (DSPE), is the main focus. Furthermore, this article presents the utilization of SPE technology for isolating common contaminants in various environmental, biological, and food specimens. We highlight the persistent challenges in SPSs and anticipate future advancements and applications of novel SPSs.

Nanomaterial-based magnetic solid-phase extraction in pharmaceutical and biomedical analysis

Magnetic solid-phase extraction (MSPE) holds significant scientific and technological interest as a novel sample preparation method for complex samples due to its easy operation, swift separation, high adsorption efficiency, and environmental friendliness. As the core of MSPE, magnetic sorbents have captured tremendous attention in recent years. Various promising nanomaterials, such as metal-organic frameworks and covalent organic frameworks, have been synthesized and utilized as sorbents in pharmaceutical and biomedical analysis. This review intends to (1) summarize recent progress of magnetic sorbents applied in this area and discuss their advantages, disadvantages, possible interaction mechanisms with the target substances; (2) explore their innovative applications in the analysis of pharmaceuticals, proteins, peptides, nucleic acids, nucleosides, metabolites, and other disease biomarkers from 2021 to 2024; (3) present the integration of MSPE with emerging analytical technologies; and (4) discuss the current challenges and future perspectives. It is expected to provide references and insights for the development of novel magnetic sorbents and their applications in bioanalysis.

Cobalt Phthalocyanine-Modified Magnetic Metal-Organic Frameworks for Specific Enrichment of Phosphopeptides

For mass spectrometry (MS)-based phosphoproteomics studies, sample pretreatment is an essential step for efficient identification of low-abundance phosphopeptides. Herein, a cobalt phthalocyanine-modified magnetic metal-organic framework (MOF) (Fe3O4@MIL-101-CoPc) was prepared and applied to enrich phosphopeptides before MS analysis. Fe3O4@MIL-101-CoPc exhibited an excellent magnetic response (74.98 emu g-1) and good hydrophilicity (7.75°), which were favorable for the enrichment. Fe3O4@MIL-101-CoPc showed good enrichment performance with high selectivity (1:1:5000), sensitivity (0.1 fmol), reusability (10 circles), and recovery (91.3%). Additionally, the Fe3O4@MIL-101-CoPc-based MS method was able to successfully detect 827 phosphopeptides from the A549 cell lysate, demonstrating a high enrichment efficiency (89.3%). This study promotes the application of postfunctionalized MOFs for phosphoproteomics analysis.

Post-synthetic modified luminescent metal-organic framework for the detection of berberine hydrochloride in a traditional Chinese herb

In this work, a novel fluorescence sensor UiO-66-PSM based on post-synthetic modified metal-organic frameworks was prepared for the detection of berberine hydrochloride (BBH) in the traditional Chinese herb Coptis. UiO-66-PSM was synthesized by a simple Schiff base reaction with UiO-66-NH2 and phthalaldehyde (PAD). The luminescence quenching can be attributed to the photo-induced electron transfer process from the ligand of UiO-66-PSM to BBH. The UiO-66-PSM sensor exhibited fast response time, low detection limit, and high selectivity to BBH. Moreover, the UiO-66-PSM sensor was successfully applied to the quantitative detection of BBH in the traditional Chinese herb Coptis, and the detection results obtained from the as-fabricated fluorescence sensing assay were consistent with those of high-performance liquid chromatography (HPLC), indicating that this work has potential applicability for the detection of BBH in traditional Chinese herbs.

Rational synthesis of FeNiCo-LDH nanozyme for colorimetric detection of deferoxamine mesylate

The accurate surveillance and sensitive detection of deferoxamine mesylate (DFO) is of great significance to ensure the safety of thalassemia major patients. Herein, we report a new nanozyme-based colorimetric sensor platform for DFO detection. First, a metal-organic framework (ZIF-67) was used as a precursor for the synthesis of FeNiCo-LDH (Layered Double Hydroxide, LDH) via an ion exchange reaction stirring at room temperature. The results of electron microscopy and nitrogen adsorption-desorption showed that FeNiCo-LDH exhibited a 3D hollow and mesopores structure, which supplied more exposed active sites and faster transfer of mass. The as-prepared FeNiCo-LDH showed superior peroxidase-like activity with a low Km and high υmax. It can catalyze the decomposition of H2O2 to generate reactive oxygen species (ROS) and further react with 3,3',5,5'-tetramethylbenzidine (TMB) to form blue oxidized TMB (oxTMB), which has a characteristic absorption at 652 nm. Once DFO was introduced, it can complex with FeNiCo-LDH and inhibit the peroxidase-like activity of FeNiCo-LDH, making the color of oxTMB lighter. The quantitative range of DFO was 0.8-28 μM with a detection limit of 0.71 μM. This established method was applied to the detection of DFO content in urine samples of thalassemia patients, and the spiked recoveries were falling between 97.7% and 109.6%, with a relative standard deviation was less than 5%, providing a promising tool for the clinical medication of thalassemia patients.

Photoreversible DNA nanoswitch-based eluent-free strategy for the direct and effective isolation of highly-active thrombin from whole blood

This study proposes an eluent-free isolation strategy for the direct isolation of thrombin from whole blood via tandem temperature/pH dual-responsive polyether sulfone monolith and photoreversible DNA nanoswitch-functionalized metal-organic framework (MOF) aerogel. Temperature/pH dual-responsive microgel immobilized on polyether sulfone monolith was adopted to remove the matrix complexity of blood sample via size/charge screening effect. Photoreversible DNA nanoswitches, comprising thrombin aptamer, aptamer complementary ssDNA (cDNA) and the azobenzene-modified ssDNA (control DNA), were functionalized on MOF aerogel to offer efficient capturing of thrombin under irradiation of ultraviolet light (365 nm), driven by electrostatic and hydrogen bond interactions. The release of captured thrombin was easily achieved by changing the complementary behaviors of DNA strands via blue light (450 nm) irradiation. Thrombin with purity higher than 95 % can be directly obtained from whole blood using this tandem isolation procedure. Fibrin production and substrate chromogenic tests showed that the released thrombin possessed high biological activity. The photoreversible thrombin capturing-release strategy is merited with eluent-free, avoiding the loss of activity of thrombin in chemical circumstances and undesired dilution, providing a robust guarantee for subsequent application.

An alkali-resistant zirconium-biligand organic framework with dual-metal centers for highly selective capture of phosphopeptides

The stability of MOFs plays one of the most important roles in material applications, while the delicate structure of MOFs suffers from the limitation of poor alkali tolerance. A new biligand Zr-MOF (biUIO-66-NH₂NO₂) with alkali-resistance performance and active functional groups has been synthesized in this study. The biUIO-66-NH₂NO₂ demonstrated a much better stability in 1% NH₃·H₂O solution than its parent material, UIO-66-NH₂. Following further immobilization of Zr⁴⁺ ions, the biDZMOF consisting of dual-zirconium centers was prepared and was further applied in global enrichment of phosphopeptides by avoiding the instability of enrichment materials in the essential alkali elution procedure for the phosphopeptide enrichment workflow. The alkali-resistant elution of phosphopeptides from the biDZMOF can be directly coupled to a tandem mass spectrometry system for peptide analysis without desalting treatment. 425 phosphopeptides in total in 3 independent samples were identified from 10 μL human saliva after enrichment with biDZMOF. The improvement in alkali resistance and successful post-modification of biUIO-66-NH₂NO₂ suggest an efficient strategy to develop new types of MOF materials for application.

Superhydrophilic nanocomposite adsorbents modified via nitrogen-rich phosphonate-functionalized ionic liquid linkers: enhanced phosphopeptide enrichment and phosphoproteome analysis of tau phosphorylation in the hippocampal lysate of Alzheimer's transgenic mice

In this study, new graphene-based IMAC nanocomposites for phosphopeptide enrichment were prepared according to the guideline of our new design strategy. Superhydrophilic polyethyleneimine (PEI) was introduced, to which a phosphonate-functionalized ionic liquid (PFIL) was covalently bound, to form superhydrophilic and cationic surface layers with high densities of nitrogen atoms, phosphonate functional groups, and high-loading metal ions. Due to the combined features of superhydrophilicity, flexibility, highly dense metal binding sites, large surface area and excellent size-exclusion effect, the fabricated nanocomposite G@mSiO₂@PEI-PFIL-Ti⁴⁺ exhibits superior detection sensitivity to enrich phosphopeptides (tryptic β-casein digest, 0.1 fmol), and extraordinary enrichment specificity to enrich phosphopeptides from a digest mixture of β-casein and bovine serum albumin (BSA) (molar ratio, 1 : 12 000). The excellent size-exclusion effect was also observed, and 27 endogenous phosphopeptides were identified in human saliva. All these results could be attributed to the unique superhydrophilic nanocomposite structure with a high density of a cationic linker modified with phosphonate functionality. Moreover, G@mSiO₂@PEI-PFIL-Ti⁴⁺ adsorbents were used to extract phosphopeptides from the tryptic digests of hippocampal lysates for quantitative phosphoproteome analysis. The preliminary results indicate that 1649 phosphoproteins, 3286 phosphopeptides and 4075 phosphorylation sites were identified. A total of 13 Alzheimer's disease (AD)-related phosphopeptides within tau proteins were detected with a wide coverage from p-Thr111 to p-Ser404, in which the amounts of some phoshopeptides at certain sites in AD transgenic mice were found statistically higher than those in wild type littermates. Besides, phosphorylated neurofilament heavy chains, a potential biomarker for amyotrophic lateral sclerosis and traumatic brain injury, were also identified. Finally, the adsorbent was applied to human cerebrospinal fluid (CSF) and blood samples. 5 unique phosphopeptides of neuroendocrine specific VGF were identified in the CSF, while many phosphopeptides originated from the nervous system were found in the blood sample. All these results suggest that our new IMAC materials exhibit unbiased enrichment ability with superior detection sensitivity and specificity, allowing the global phosphoproteome analysis of complicated biological samples more convincible and indicating the potential use in disease diagnosis.