Green synthesis of monolithic enzyme microreactor based on thiol-ene click reaction for enzymatic hydrolysis of protein.

In this study, a monolithic enzyme reactor based on a strategy of green synthesis was successfully prepared in a capillary with trypsin immobilized by "thiol-ene" click reaction. A polymer of poly(butyl methacrylate-co-α-methacrylic acid-co-ethylene glycol dimethacrylate) was prepared in a mixture of 1-butyl-3-methylimidazolium tetrafluoroborate and choline chloride/ethylene glycol as the support of enzyme reactor. After "thiol-ene" reaction was used for enzyme immobilization, the Michaelis constants and maximum reaction rate of the resulting immobilized enzyme reactors (IMER) were determined by capillary electrophoresis to be 2.1 mmol/L and 0.028 µmol/min, respectively. The enzymatic hydrolysis of the enzyme reactor under different experimental conditions were investigated. A on-line digestion of bovine serum albumin (BSA) on the new IMER can be achieved within 50 s, up to 864 times faster than in-solution digestion (12 h). BSA can be well digested and the numbers of identified peptides were 73 with the coverage rates of 82.7%. The IMER was further used for the analysis of protein extracts from rat liver, and 1034 protein groups were identified. All these results demonstrated that such a click reaction based IMER would be of great prospect in the high throughput analysis for proteome with high confidence.

Preparation of graphene oxide incorporated monolithic chip based on deep eutectic solvents for solid phase extraction.

A monolithic chip incorporated with graphene oxide (GO) based on deep eutectic solvents (DESs) was developed for solid phase extraction (SPE). The carboxylated GO was modified with p-aminostyrene (pAS) by amidation, and the obtained GO (pAS-COOH-GO) was covalently incorporated into poly(butyl methacrylate-co-ethylene glycol dimethyl methacrylate) monolithic chip. Due to the high viscosity characteristics of DESs, a uniform pAS-COOH-GO incorporated monolithic chip with good permeability can be achieved. A systematic study of the preparation parameters on the performance of the resulting monolith was carried out, including the content of pAS-COOH-GO, DESs composition and porogen ratio. The resulting pAS-COOH-GO incorporated monolith was characterized by nitrogen adsorption, scanning electron microscopy, and transmission electron microscopy. The GO-doped monolithic chip can be used for SPE of polycyclic aromatic hydrocarbons (phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, benzo(a) pyrene, dibenzo(a,h)anthracene and inden(1,2,3,-cd)pyrene). The recoveries were all higher than 90%, which was about twice as high as that of the monolithic chip prepared without GO. By comparing the SPE results with that of GO free monolithic chip, good enrichment effects were demonstrated on the pAS-COOH-GO incorporated monolithic chip.

Floating molecularly imprinted polymers based on liquid crystalline and polyhedral oligomeric silsesquioxanes for capecitabine sustained release.

Molecularly imprinted polymers (MIPs) have drawn extensive attention as carriers on drug delivery. However, most of MIPs suffer from insufficient drug loading capacity, burst release of drugs and/or low bioavailability. To solve the issues, this study designed an imprinted material with superior floating nature for oral drug delivery system of capecitabine (CAP) rationally. The MIPs was synthesized in the presence of 4-methylphenyl dicyclohexyl ethylene (liquid crystalline, LC) and polyhedral oligomeric silsesquioxanes (POSS) via polymerization reaction. The LC-POSS MIPs had extended release of the template molecules over 13.4 h with entrapment efficiency of 20.53%, diffusion coefficient of 2.83 × 10-11 cm2 s-1, and diffusion exponent of 0.84. Pharmacokinetic studies further revealed the prolong release and high relative bioavailability of CAP in vivo of rats, showing the effective floating effect of the LC-POSS MIPs. The in vivo images revealed visually that the gastroretentive time of the LC-POSS MIPs was longer than non-LC-POSS imprinted polymers. The physical characteristics of the polymers were also characterized by nitrogen adsorption experiment, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry analysis. As a conclusion, the LC-POSS MIPs can be used as an eligible CAP carrier and might hold great potential in clinical applications for sustained release drug.

Improving affinity of boronate capillary monolithic column for microextraction of glycoproteins with hydrophilic macromonomer.

A novel boronate affinity monolithic capillary was prepared by in-situ polymerization and successfully applied to microextraction (PMME) of glycoproteins. Using functional monomer 3-(acrylamido)phenylboronic acid (AAPBA) and hydrophilic macromonomer oligo (ethylene glycol) methyl ether methacrylate (OEG), crosslinking monomer ethylene glycol dimethacrylate (EDMA) and binary porogens of n-propanol and 1,4-butanediol, poly(AAPBA-co-OEG-co-EDMA) monolith was made with uniform structure and good column permeability. Systematic optimization of preparation conditions were performed, including AAPBA content, the molar ratio of AAPBA to OEG, crosslinking monomer content, n-propanol content in binary porogens. The optimized OEG boronic monolithic column was characterized with infrared absorption spectroscopy, field emission scanning electron microscopy and N2 adsorption experiment. In this study, extraction performance was tested by PMME of horseradish peroxidase (HRP) and ovalbumin (OVA). Compared with the corresponding OEG-free boronate monolith, the recovery of HRP and OVA was significantly improved to 97.51% and 93.97% (RSDs < 5.0%), respectively, which increased by 30.0%. Moreover, the newly developed monolith was further applied for extraction of HRP and OVA from the egg white samples with the recovery of 96.10% and 92.24% (RSDs < 7.5%), respectively. The results suggested that the introduction of hydrophilic macromonomer into boronic material is an effective method to improve the affinity of boronate affinity chromatography to glycoproteins.