Solvent and monomer regulation synthesis of core-shelled magnetic ß-cyclodextrin microporous organic network for efficient extraction of estrogens in biological samples prior to HPLC analysis.

The abnormal estrogens levels in human body can cause many side effects and diseases, but the quantitative detection of the trace estrogens in complex biological samples still remains great challenge. Here we reported the fabrication of a novel core-shell structured magnetic cyclodextrin microporous organic network (Fe3O4@CD-MON) for rapid magnetic solid phase extraction (MSPE) of four estrogens in human serum and urine samples prior to HPLC-UV determination. The uniform spherical core-shell Fe3O4@CD-MONs was successfully regulated by altering the reactive monomers and solvents. The Fe3O4@CD-MONs owned high specific surface area, good hydrophobicity, large superparamagnetism, and abundant extraction sites for estrogens. Under optimal conditions, the proposed MSPE-HPLC-UV method provided wide linearity range (2.0-400 µg L-1), low limits of detection (0.5-1.0 µg L-1), large enrichment factors (183-198), less adsorbent consumption (3 mg), short extraction time (3 min), and good stability and reusability (at least 8 cycles). The established method had also been successfully applied to the enrichment and detection of four estrogens in serum and urine samples with a recovery of 88.4-105.1 % and a relative standard deviation of 1.0-5.9 %. This work confirmed the feasibility of solvent and monomer regulation synthesis of Fe3O4@CD-MON composites, and revealed the great prospects of magnetic CD-MONs for efficient enrichment of trace estrogens in complex biological samples.

Monomer-mediated fabrication of microporous organic network@silica microsphere for reversed-phase/hydrophilic interaction mixed-mode chromatography.

Microporous organic networks (MONs) are promising in high performance liquid chromatography (HPLC) with large specific surface area, good hydrophobicity and stability. However, their superhydrophobic structures restrict MONs-based HPLC only in reversed-phase mode. To decrease the hydrophobicity of pristine MONs and to expand their broad application in HPLC, here we described the monomer-mediated fabrication of core-shell MON-2COOH@SiO2 microspheres for reversed-phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode chromatography for the first time. The -COOH groups were introduced into MONs' skeleton to improve their hydrophilicity and to provide hydrophilic interaction sites. The MON-2COOH was grafted onto silica via a monomer mediated method to produce monodispersed core-shell microspheres. By adjusting the concentration of reactants, the thickness of MON-2COOH shell was easily manipulated. The packed MON-2COOH@SiO2 column showed high resolution and selectivity for separating both hydrophobic (alkylbenzenes, polycyclic aromatic hydrocarbons, anilines and phenols) and hydrophilic (nucleoside and nucleic bases) probes, highlighting the promise of MONs in mixed-mode HPLC. The MON-2COOH@SiO2 column also achieved good separation to sulfonamides, nonsteroidal anti-inflammatory drugs, flavonoids and phenylurea herbicides, and offered better resolution than commercial C18 and pristine SiO2 column. Multiple retention mechanisms were also found on MON-2COOH@SiO2 packed column, underlining the great potential of MONs in mixed-mode HPLC.

[Expression of TFPI-2 gene and its promoter methylation in acute myeloid leukemia].

The aim of this study was to detect the mRNA expression of tissue factor pathway inhibitor-2 ( TFPI-2) and its methylation in bone marrow mononuclear cells from acute myeloid leukemia (AML) patients and to explore its significance in AML. Bone marrow mononuclear cells were isolated from newly diagnosed AML patients (n = 33), complete remission AML patients (n = 19), relapsed/refractory AML patients (n = 12) and iron deficiency anemia patients (control group, n = 15). Expression of TFPI-2 mRNA was detected with real-time quantitative PCR (RT-PCR) and the methylation of CpG island in its promoter was detected with methylation-specific PCR (MSP). The results showed that the expression of TFPI-2 mRNA in newly diagnosed AML, complete remission AML and relapsed/refractory AML patients was much lower than that in the controls (P < 0.05). Furthermore, its expression in relapsed/refractory AML patients was lower than that in newly diagnosed AML patients (P = 0.006). Compared with complete remission AML patients, the expression of TFPI-2 mRNA in newly diagnosed AML patients was significantly reduced (P = 0.030). The percentage of TFPI-2 promoter methylation in AML patients was 64.63% (42/64). In newly diagnosed AML group, complete remission AML group and relapsed/refractory AML group,the percentages of TFPI-2 promoter methylation were 66.67% (22/33), 52.63% (10/19) and 83.33% (10/12) (P > 0.05), respectively. The optical density ratio of TFPI-2 mRNA expression was 0.165 (0.005-2.099) in methylated AML patients, and 0.597 (0.011-2.787) in unmethylated AML patients (P < 0.05). Methylation of TFPI-2 gene promoter was not detected in control patients. After 2 courses of chemotherapy, the level of TFPI-2 mRNA was much higher in the CR group than that in the non-CR group (P < 0.05). It is concluded that the down-regulation or silence of TFPI-2 gene potentially results from its promoter methylation, and the expression level of TFPI-2 and the methylation status of its promoter may be used as indicators of risk stratification and evaluation of disease progress.