Fabrication of microporous organic network@silica composite for high-performance liquid chromatographic separation of drugs and proteins

Click postsynthesis of microporous organic network@silica composites for reversed-phase/hydrophilic interaction mixed-mode chromatography

Recently, the good physical and chemical properties, well-defined pore architectures, and designable topologies have made microporous organic networks (MONs) excellent potential candidates in high-performance liquid chromatography (HPLC). However, their superior hydrophobic structures restrict their application in the reversed-phase mode. To solve this obstacle and to expand the application of MONs in HPLC, we realized the thiol-yne "click" postsynthesis of a novel hydrophilic MON-2COOH@SiO₂-MER (MER denotes mercaptosuccinic acid) microsphere for reversed-phase/hydrophilic interaction mixed-mode chromatography. SiO₂ was initially decorated with MON-2COOH using 2,5-dibromoterephthalic acid and tetrakis(4-ethynylphenyl)methane as monomers, and MER was then grafted via thiol-yne click reaction to yield MON-2COOH@SiO₂-MER microspheres (5 μm) with a pore size of ~1.3 nm. The -COOH groups in 2,5-dibromoterephthalic acid and the post-modified MER molecules considerably improved the hydrophilicity of pristine MON and enhanced the hydrophilic interactions between the stationary phase and analytes. The retention mechanisms of the MON-2COOH@SiO₂-MER packed column were fully discussed with diverse hydrophobic and hydrophilic probes. Benefiting from the numerous -COOH recognition sites and benzene rings within MON-2COOH@SiO₂-MER, the packed column exhibited good resolution for the separation of sulfonamides, deoxynucleosides, alkaloids, and endocrine-disrupting chemicals. A column efficiency of 27,556 plates per meter was obtained for the separation of gastrodin. The separation performance of the MON-2COOH@SiO₂-MER packed column was also demonstrated by comparing with those of MON-2COOH@SiO₂, commercial C18, ZIC-HILIC, and bare SiO₂ columns. This work highlights the good potential of the thiol-yne click postsynthesis strategy to construct MON-based stationary phases for mixed-mode chromatography.

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.

Utilizing Heterostructured Porous Particles to Improve Traditional Paper Chromatography for Spontaneous Protein Separation

Chromatography is a classical technique for protein separation. However, the chromatography column is filled with tightly packed separation materials and requires an additional pressurizing pump to propel the flow of fluidic samples, largely restraining their applications. Here, we combine heterostructured porous particles with paper strips, realizing spontaneous separation of similarly sized proteins. The interconnected nanofibrous structure and good hydrophility of paper strips enable the spontaneous flow of the liquid sample, and the heterostructured porous particles provide versatile tools for protein separation via electrostatic interaction. The fabricated paper strips are inexpensive, user-friendly, and disposable and exhibit good separation performance. This work may offer a new avenue for fabricating on-site bioseparation tools and purifying various biomacromolecules.

Hollow-Structured Microporous Organic Networks Adsorbents Enabled Specific and Sensitive Identification and Determination of Aflatoxins

Aflatoxin (AFT) contamination, commonly in foods and grains with extremely low content while high toxicity, has caused serious economic and health problems worldwide. Now researchers are making an effort to develop nanomaterials with remarkable adsorption capacity for the identification, determination and regulation of AFT. Herein, we constructed a novel hollow-structured microporous organic networks (HMONs) material. On the basis of Fe3O4@MOF@MON, hydrofluoric acid (HF) was introduced to remove the transferable metal organic framework (MOF) to give hollow MON structures. Compared to the original Fe3O4@MOF@MON, HMON showed improved surface area and typical hollow cavities, thus increasing the adsorption capacity. More importantly, AFT is a hydrophobic substance, and our constructed HMON had a higher water contact angle, greatly enhancing the adsorption affinity. From that, the solid phase extraction (SPE-HPLC) method developed based on HMONs was applied to analyze four kinds of actual samples, with satisfied recoveries of 85-98%. This work provided a specific and sensitive method for the identification and determination of AFT in the food matrix and demonstrated the great potential of HMONs in the field of the identification and control of mycotoxins.