Preparation of mixed-mode weak cation exchange magnetic solid-phase extraction sorbent and its application in the extraction of 21 illicit drugs from wastewater.

The detection of illicit drugs in wastewater can effectively monitor and evaluate the trend of illicit drug abuse. A novel mixed-mode cation exchange magnetic sorbent Fe3O4 @poly(ST/DVB/MA-COOH) was prepared and firstly applied as magnetically dispersed solid phase extraction material to efficiently, rapidly, and selectively extract 21 illicit drugs from wastewater. The selectivity of the sorbent was mainly attributed to the electrostatic interaction. The effects of Fe3O4 @poly(ST/DVB/MA-COOH) preparation and extraction conditions on the adsorption performance were thoroughly discussed. Among the 21 illicit drugs, the absolute extraction recovery values for 19 illicit drugs were greater than 80 % and the entire adsorption process could be achieved in one minute. Subsequently, the Fe3O4 @poly(ST/DVB/MA-COOH) sorbent combined with UHPLC-MS/MS was used to establish a quantitative method for the effectively extracted 19 illicit drugs in wastewater. The method had a good determination coefficient in the range of 0.2-200 ng/L and the limits of detection of the method were 0.03-0.67 ng/L. The spiked recovery values were in the range of 87.0-119.6 %. Finally, the method was successfully applied to the detection of 19 illicit drugs in wastewater samples and also compared with the commonly used SPE method. The obtained results indicate that Fe3O4 @poly(ST/DVB/MA-COOH) has great advantages in the detection of illicit drugs in wastewater.

Preparation and application of polystyrene-divinylbenzene sorbent with weak cation-exchange character for the selective extraction of illicit drugs in environmental water.

A novel mixed-mode weak cation-exchange sorbent (PS-DVB-WCX-II) was prepared by the modification of polystyrene-divinylbenzene with mercaptosuccinic acid for the selective extraction of illicit drugs in environmental water. The PS-DVB-WCX-II was synthesized through the Friedel-Crafts acylation reaction on the surface of polystyrene-divinylbenzene, followed by nucleophilic substitution reaction and thiol-ene click reaction. The sorbent can selectively absorb illicit drugs through the reverse-phase interactions provided by benzene ring on the polymer backbone and the ion-exchange interactions provided by functional group (-COOH). As compared with the extraction performance of three commercial SPE cartridges, it was found that the prepared sorbent had better adsorption performance with the recovery values between 84.1% and 106.0% for the selected 11 illicit drugs under the optimized SPE conditions. Illicit drugs in environmental water were extracted by the sorbent, prior to the detection of UHPLC-MS/MS. Two quantitative methods were established respectively for the detection of 11 illicit drugs in different matrices of river water and wastewater. Both methods had good determination coefficient (r2>0.992) in the range of 0.5-50 ng/L, 2.5-250 ng/L, 5-500 ng/L, and low limits of detection (S/N = 3) of 0.17-1.67 ng/L. In the real wastewater samples, the concentration of morphine was 18.3-126.3 ng/L, and the methamphetamine was 12.7-27.4 ng/L. Meanwhile, PS-DVB-WCX-II was compared with Oasis MCX and Oasis HLB in the detection of real wastewater samples. The results revealed that PS-DVB-WCX-II and Oasis MCX had better performance in absorbing methamphetamine than Oasis HLB, and PS-DVB-WCX-II had better ability to remove the matrix. The results suggested that the prepared weak cation-exchange sorbent had the potential in the application of illicit drug detection in environmental water.

Rapid de novo generation of antigen specific human B cells with expression of Blimp-1 and AID by in vitro immunization.

In vitro immunization with antigens and cytokines triggers specific human B-cell response in short periods and is therefore superior to conventional in vivo immunization for antibody development. However, this new technology is limited by low efficiency, poor reproducibility, and requirement of pre-immunized lymphocytes. In this study, we demonstrate a novel method for de novo inducing antigen-specific human B cells in vitro. Unlike previous in vitro immunization of unfractionated PBMCs, we firstly optimized the conditions for inducing monocyte-derived dendritic cells (DCs) to efficiently capture, process, and present antigens. Instead of using the conventional method to activate Th2 cells for in vitro immunization, we succeeded to differentiate naïve CD4+ T cells into T follicular helper (Tfh) cells using antigen-sensitized DCs and cytokine cocktail. We discovered the differentiated T cells expressed ICOS, PD-1, BCL-6, and IL-21 at high levels. After 12 days of T-B co-culture, we observed induced T cells efficiently promoted naïve B cells to differentiate into plasmablasts secreting antigen-specific antibodies, with expression of Blimp-1 and AID related to affinity maturation and class switching. Thus, we established a new co-culture system with naïve lymphocyte populations for de novo acquisition of specifically in vitro immunized B cells potentially for development of therapeutic antibodies, which also provides novel insights into understanding the complex interactions among immune cells in lymph nodes.

Novel [99mTcN]2+ labeled EGFR inhibitors as potential radiotracers for single photon emission computed tomography (SPECT) tumor imaging.

The epidermal growth factor receptor (EGFR) is overexpressed in many cancers, including breast, ovarian, endometrial and non-small cell lung cancer. An EGFR-specific imaging agent could facilitate clinical evaluation of primary tumors or metastases. To achieve this goal, 4-(2-aminoethylamino)-6,7-dimethoxyquinazoline (ADMQ) was synthesized based on a 4-aminoquinazoline core and then conjugated with N-mercapto- acetylglycine (MAG) and N-mercaptoacetyltriglycine (MAG3), respectively, to give compounds 1 and 2. The final complexes [99mTcN]-1 and [99mTcN]-2 were successfully obtained with radiochemical purities of >99% and >98% as measured by radio-HPLC. No decomposition of the two complexes at room temperature was observed over a period of 2 h. Their partition coefficients indicated they were hydrophilic and the electrophoresis results showed they were negatively charged. Biodistribution in tumor-bearing mice demonstrated that the two new complexes showed tumor accumulation, high tumor-tomuscle (T/M) ratios and fast clearance from blood and muscle. Between the two compounds, the 99mTcN-MAG3-ADMQ ([99mTcN]-2) showed the better characteristics, with the tumor/muscle and tumor/blood ratios reached 2.11 and 1.90 at 60 min post-injection, 4.20 and 1.10 at 120 min post-injection, suggesting it could be a promising radiotracer for SPECT tumor imaging.

Design and synthesis of novel quinazoline nitrogen mustard derivatives as potential therapeutic agents for cancer.

Thirteen novel quinazoline nitrogen mustard derivatives were designed, synthesized and evaluated for their anticancer activities in vitro and in vivo. Cytotoxicity assays were carried out in five cancer cell lines (HepG2, SH-SY5Y, DU145, MCF-7 and A549) and one normal human cell line (GES-1), in which compound 22b showed very low IC50 to HepG2 (the IC50 value is 3.06 µM), which was lower than Sorafenib. Compound 22b could inhibit cell cycle at S and G2/M phase and induce cell apoptosis. In the HepG2 xenograft model, 22b exhibited significant cancer growth inhibition with low host toxicity in vivo.

Synthesis and evaluation of novel F-18 labeled 4-aminoquinazoline derivatives: potential PET imaging agents for tumor detection.

Three novel (18)F-labeled 4-aminoquinazoline derivatives, N-(3-chloro-4-fluorophenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]1), N-(3-ethynylphenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]2), and N-(3-bromophenyl)-6-(2-[(18)F]fluoroethoxy)-7-methoxyquinazolin-4-amine([(18)F]3) were synthesized and radiolabeled by two-step reaction with overall radiochemical yield of 21-24% (without decay corrected). Then we carried out their biodistribution experiments in S180 tumor-bearing mice. Results showed that they had certain concentration accumulation in tumor and fast clearance from muscle and blood. It was encouraging that [(18)F]3 was competitive among three (18)F-labeled 4-aminoquinazoline derivatives in some aspects such as tumor/muscle uptake ratio reaching 7.70 at 60 min post-injection, tumor/blood uptake ratio reaching 6.61 at 120 min post-injection. So we compared radioactivity characteristics of [(18)F]3 with those of [(18)F]-FDG and L-[(18)F]-FET in the same animal model. The absolute radioactivity uptake of [(18)F]3 in tumor reached 3.31 at 60 min p.i., which was slightly higher than [(18)F]-FDG (2.16) and L-[(18)F]-FET (2.75) at the same time phase. For [(18)F]3, tumor/muscle uptake ratio peaked 7.70 at 60 min, which was obviously superior to those of [(18)F]-FDG and L-[(18)F]-FET at all time points. The tumor/brain uptake ratios of [(18)F]3 were 10.36, 17.42, 41.11 at 30 min, 60 min and 120 min post-injection, respectively, and are much higher than those of L-[(18)F] FET (2.54, 2.92 and 2.95) and [(18)F]-FDG (0.61, 1.02 and 1.33) at the same time points. All these results indicate that [(18)F]3 is promising to become a potential PET tumor imaging agent.