Micro gas chromatographic column with copper benzene-1,3,5-tricarboxylate modified by multilayer fluorinated graphene as a stationary phase.

A composite material was synthesized at room temperature by performing modification of the copper benzene-1,3,5-tricarboxylate (HKUST-1) metal-organic framework material by multilayer fluorinated graphene (FG). The FG-HKUST-1 composite was used as a stationary phase for a micro gas chromatography column (µGCC) fabricated using micro-electro-mechanical system (MEMS) technology. The separation results showed that the µGCC with the FG-HKUST-1 composite stationary phase achieved a baseline separation of C1-C4 in 8 min. The retention factors for C2-C4 were 2.13, 7.14, and 12.04, respectively. The maximum relative standard deviation (RSD) of the retention times was 0.14 %. The difference in the retention time between methane and ethane was 1.11 min, with a resolution of 9.2 for methane and ethane. The retention factor of ethane and the resolution of methane and ethane were increased by 166 % and 114 %. Therefore, this µGCC is promising for separating light hydrocarbons with widely differing concentrations.

Characterization of the Hemolytic Activity of Mastoparan Family Peptides from Wasp Venoms.

Biologically active peptides have attracted increasing attention in research on the development of new drugs. Mastoparans, a group of wasp venom linear cationic α-helical peptides, have a variety of biological effects, including mast cell degranulation, activation of protein G, and antimicrobial and anticancer activities. However, the potential hemolytic activity of cationic α-helical peptides greatly limits the clinical applications of mastoparans. Here, we systematically and comprehensively studied the hemolytic activity of mastoparans based on our wasp venom mastoparan family peptide library. The results showed that among 55 mastoparans, 18 had strong hemolytic activity (EC50 ≤ 100 µM), 14 had modest hemolytic activity (100 µM < EC50 ≤ 400 µM) and 23 had little hemolytic activity (EC50 > 400 µM), suggesting functional variation in the molecular diversity of mastoparan family peptides from wasp venom. Based on these data, structure-function relationships were further explored, and, hydrophobicity, but not net charge and amphiphilicity, was found to play a critical role in the hemolytic activity of mastoparans. Combining the reported antimicrobial activity with the present hemolytic activity data, we found that four mastoparan peptides, Parapolybia-MP, Mastoparan-like peptide 12b, Dominulin A and Dominulin B, have promise for applications because of their high antimicrobial activity (MIC ≤ 10 µM) and low hemolytic activity (EC50 ≥ 400 µM). Our research not only identified new leads for the antimicrobial application of mastoparans but also provided a large chemical space to support the molecular design and optimization of mastoparan family peptides with low hemolytic activity regardless of net charge or amphiphilicity.

Characterization of the Molecular Diversity and Degranulation Activity of Mastoparan Family Peptides from Wasp Venoms.

Wasp stings have become an increasingly serious public health problem because of their high incidence and mortality rates in various countries and regions. Mastoparan family peptides are the most abundant natural peptides in hornet venoms and solitary wasp venom. However, there is a lack of systematic and comprehensive studies on mastoparan family peptides from wasp venoms. In our study, for the first time, we evaluated the molecular diversity of 55 wasp mastoparan family peptides from wasp venoms and divided them into four major subfamilies. Then, we established a wasp peptide library containing all 55 known mastoparan family peptides by chemical synthesis and C-terminal amidation modification, and we systematically evaluated their degranulation activities in two mast cell lines, namely the RBL-2H3 and P815 cell lines. The results showed that among the 55 mastoparans, 35 mastoparans could significantly induce mast cell degranulation, 7 mastoparans had modest mast cell degranulation activity, and 13 mastoparans had little mast cell degranulation activity, suggesting functional variation in mastoparan family peptides from wasp venoms. Structure-function relationship studies found that the composition of amino acids in the hydrophobic face and amidation in the C-terminal region are critical for the degranulation activity of mastoparan family peptides from wasp venoms. Our research will lay a theoretical foundation for studying the mechanism underlying the degranulation activity of wasp mastoparans and provide new evidence to support the molecular design and molecular optimization of natural mastoparan peptides from wasp venoms in the future.

A semi-packed gas chromatography column with high-density elliptic cylindrical posts.

Semi-packed columns are microfabricated gas chromatography columns which have a large surface area and high aspect ratio. In this paper, a new semi-packed column with high-density elliptic cylindrical posts (SCHECP) made by a micro-electro-mechanical system (MEMS) technique was reported. Compared to a semi-packed column with cylindrical posts (SCCP) under the same effective width, the surface area and aspect ratio of SCHECP were improved by 71.19% and 76.47%, respectively. To compare the performance of these two semi-packed columns, SCHECP and SCCP were fabricated. A 10-nm thick alumina film was deposited as the stationary phase by atomic layer deposition technique to ensure the uniformity and repeatability of the stationary-phase film. A contrast experiment was conducted, and the results showed that compared with SCCP, better separation performance was realized in SCHECP due to the increase in surface area and aspect ratio. The number of theoretical plates of nonane was increased by 541.84%, and the tailing factor was decreased by 54.31%.

In situ poly I:C released from living cell drug nanocarriers for macrophage-mediated antitumor immunotherapy.

Immunotherapy is one of the most promising approaches to inhibit tumor growth and metastasis by activating host immune functions. However, the arising problems such as low immune response caused by complex tumor microenvironment and extremely systemic immune storm still limit the clinical applications of immunotherapy. Here, we construct Poly I: C-encapsulated poly (lactic-co-glycolic acid) nanoparticles (PLP NPs) with a slow release profile. A biomimetic system (MPLP), which loads PLP NPs on the surface of bone marrow-derived macrophage (BMDM) via the maleimide-thiol conjugation, is synthesized to effectively deliver PLP, control drug release and activate the tumor-specific immune response in situ. The results show that PLP NPs loading does not affect the activity and function of BMDM. Then, BMDM acts as a living cell drug vehicle and promotes the accumulation of PLP NPs in tumors, where Poly I: C is released from PLP NPs and reprograms BMDM into tumoricidal M1 macrophage. Furthermore, MPLP triggers potent antitumor immune responses in vivo and effectively inhibits local and metastatic tumors without causing adverse pathological immune reactions. This study offers an inspiration to facilitate clinical translation through the delivery of drugs by living immune cells for future anticancer therapy.

Smart gold nanocages for mild heat-triggered drug release and breaking chemoresistance.

Chemotherapy is an important modality available for cancer treatment. However, the present chemotherapy is still far from being satisfactory mainly owing to the severe side effects of the chemotherapeutic agents and drug resistance of cancer cells. Thus, reversing drug resistance by constructing an ideal chemotherapeutic strategy with the least side effects and the best efficacy is greatly needed. Here, we designed a smart nanosystem of thermo-sensitive liposome coated gold nanocages with doxorubicin (DOX) loading (LAD) for near-infrared (NIR)-triggered drug release and chemo-photothermal combination therapy. The biocompatible liposomes coating facilitated the cellular uptake of LAD and meanwhile avoided drug leakage during the circulation. More importantly, LAD exhibited controllable photothermal conversion property and produced mild heat under NIR irradiation, which not only triggered DOX release and transferred DOX from lysosome to nucleus, but also elicited the mild heat cell killing effect to improve the curative efficiency. Further mechanism study revealed that mild heat could reverse drug resistance by down-regulation of the chemoresistance-related markers (e.g., HSF-1, p53, P-gp), and inhibited DOX export and increased drug sensitiveness, thereby prominently increased the anticancer efficiency. This versatile nanoplatform with enhanced curative efficacy and lower side effect is promising to apply in the field of drug controlled release and combination tumor therapy.

Tumor-targeted nanoplatform for in situ oxygenation-boosted immunogenic phototherapy of colorectal cancer.

Advanced colorectal cancer has a high mortality rate since conventional treatments have limited therapeutic effects and poor prognosis with high risks of metastasis and recurrence. Photodynamic therapy (PDT) is a promising treatment modality for the eradication of colorectal cancer, but its curative efficacy is severely affected by tumor hypoxia. Herein, we developed a core-shell gold nanocage coated with manganese dioxide and hyaluronic acid (AMH) for targeted delivery to colorectal tumors and oxygenation-boosted immunogenic phototherapy in situ. The AMH nanoparticles can generate abundant oxygen from mild acidic/H2O2 medium, which can further enhance the PDT efficacy of AMH itself under near infrared (NIR) irradiation. Meanwhile, AMH-based PDT induced immunogenic cell death (ICD) of tumor cells with damage-associated molecular patterns (DAMPs) release and facilitated the dendritic cells (DCs) maturation to further potentiate the systematic antitumor immunity against advanced tumors. In vivo experiment results exhibited that AMH nanoparticles not only had the ability of targeting tumor but also in situ produced sufficient oxygen to relieve the tumor hypoxia. Furthermore, AMH-mediated oxygen-boosted immunogenic PDT effectively inhibited the tumor growth and recurrence. Thus, this work provides a potent targeted delivery nanoplatform for enhanced immunogenic PDT against advanced cancers. STATEMENT OF SIGNIFICANCE: Local hypoxic tumor microenvironment not only greatly limits the photodynamic therapy (PDT) efficacy, but also has an association with tumor invasiveness and metastasis. This study provides an AMH nanoparticle for targeted delivery to colorectal tumors and oxygenation-boosted immunogenic PDT in situ. AMH nanoparticle exhibits a good tumor-targeted ability to in situ produce abundant oxygen to relieve the tumor hypoxia, and initiates the potent oxygen-boosted immunogenic PDT effect under NIR irradiation to effectively inhibit the growth and recurrence of colorectal tumor. This oxygen-boosted immunogenic PDT nanosystem can be a promising candidate for advanced tumor treatment.

Removal of residual functionalized ionic liquids from water by ultrasound-assisted zero-valent iron/activated carbon.

Numerous applications of ionic liquids (ILs) are often accompanied by the generation of aqueous wastes. Due to the high toxicity and poor biodegradability of ILs, effective chemical treatment is of great importance for their removal from aqueous solution. In this work, an ultrasound-assisted zero-valent iron/activated carbon (US-ZVI/AC) micro-electrolysis technique was used to degrade residual functionalized ILs, 1-butyl-3-methyl benzimidazolium bromide ([BMBIM]Br) and 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) in aqueous solution, and the degradation degree, degradation kinetics and possible degradation pathways were investigated. It was shown that the degradation of these functionalized ILs was highly efficient in the US-ZVI/AC system, and the degradation degree was as high as 96.1% and 92.9% in 110 min for [BMBIM]Br and [AMIM]Cl, respectively. The degradation of [BMBIM]Br could be described by the second-order kinetics model, and [BMBIM]+ was decomposed in two ways: (i) sequential cleavage of N-alkyl side chain of the cation produced three intermediates; (ii) the 2-positioned H atoms of the benzimidazolium ring were first oxidized, and then the imidazolium ring was opened. The degradation of [AMIM]Cl followed the first-order kinetics rule, and the 2,4,5-positioned H atoms of the imidazolium ring were oxidized to induce ring opening. In addition, the removal of total organic carbon was found to be >87%, which indicates that most of the ILs was mineralized in the degradation process. These results suggest that ultrasound-assisted ZVI/AC micro-electrolysis is highly effective for the removal of residual functionalized ILs from aqueous environment.

[Research progress of micro-electro-mechanical systems micro gas chromatography columns].

The gas chromatography (GC) column is a key component of the gas chromatographic system, which is mainly used for the separation of mixed gas components. Compared with the traditional GC column, the micro GC column based on micro-electro-mechanical systems (MEMS) technology has the advantages of lighter weight, smaller volume, lower power consumption, and faster analysis. Furthermore, it can be integrated into a portable instrument, such as a miniaturized GC. The research progress of micro GC columns based on MEMS technology is summarized in this paper. First, the theoretical basis of the MEMS micro GC column is stated. Then, the layout and inner structure of the MEMS micro GC column, the stationary-phase support, and the preparation of the stationary phase are summarized. Finally, trends in the development of MEMS micro GC columns are discussed.

[High-aspect-ratio gas chromatography column based on micro-electro-mechanical system technology].

Miniaturization of gas chromatography (GC) columns is one of the key problems associated with microminiaturization of a chromatograph. In this study, a GC column with high-aspect-ratio microchannel based on micro-electro-mechanical system (MEMS) technology has been designed and manufactured. Simulation and analysis by the COMSOL software revealed that the GC column has even velocity field distribution, which is crucial for improving the separation efficiency of the column. The results show that heavy hydrocarbons (C6-C10) and compounds of benzene series can be successfully separated. The number of theoretical plate is 14028 plates/m, and the resolution of C7-C8 is 10.82. Due to its advantages of smaller volume, lower energy consumption, and better separation performance, the GC column can be applied in micro gas chromatography.

Improved separation of micro gas chromatographic column using mesoporous silica as a stationary phase support.

In this paper, a novel and facile way to improve the separation of micro gas chromatographic column is presented which utilizes the mesoporous silica thin film as the stationary phase support. A serpentine semi-packed column is fabricated based on a micro-electro-mechanical system (MEMS) technology and polydimethylsiloxane is used as the stationary phase. The chromatographic resolution of C6-C7 increases from unseparated to 7.44 after depositing mesoporous silica thin film as the stationary phase support in the separation of a mixture of heavy hydrocarbons (C6-C10), and the separation efficiency is as high as 9290 plates/m. Meanwhile, in the separation of a mixture of benzene series (gas mixtures of benzene, toluene and paraxylene), the chromatographic resolution of benzene and toluene can also be increased by 483%. Those outstanding results indicate that using the mesoporous silica as the stationary phase support is an effective way to improve the separation efficiency of the gas chromatographic column.

A micro gas chromatographic column with embedded elliptic cylindrical posts.

In this paper, a novel embeded elliptic cylindrical posts (ECPs) with large surface area and wide effective width, which could support more stationary phase and decrease the pressure drop, is applied on the micro-fabricated gas chromatographic (µGC) column. Compared with µGC column with cylindrical posts (CPs), the surface area and effective width of µGC column with ECPs are increased by 29% and 30%. Separation experiments are performed under the same head pressure at column inlet: in experiments of separating mixture 1, the column efficiency of the µGC column with ECPs for C9 has a 76% improvement, and the separation resolution between C8 and C9 also has a 34% improvement; in experiments of separating mixture 2, seven kinds of analytes can be identified by the µGC column with ECPs less than ten minutes, while, only six kinds can be identified by the µGC column with CPs in almost the same time. In detail, the column efficiency of the µGC column with ECPs for toluene has a 129% improvement, and the separation resolution between benzene and toluene also has a 56.4% improvement. Hence, the µGC column with the inner structures of ECPs is a valid means to improve column efficiency and resolution in a lower pressure drop.

Pore size effect of mesoporous silica stationary phase on the separation performance of microfabricated gas chromatography columns.

Microfabricated semi-packed gas chromatography (GC) columns coated with two kinds of mesoporous silica (MS) stationary phase have been explored and compared in this paper. The micro GC (µGC) columns are fabricated by microelectromechanical system (MEMS) technique. MSs with pore size of 2 and 5 nm are prepared using two different soft-templates and deposited on the inner surface of the µGC columns by dip-coating. For the first time, the influence of pore size of MS stationary phase on the separation performance in a µGC column has been investigated. As demonstrated, the mixtures of light alkanes (C1-C4) or heavy alkanes (C5-C10) can be well separated in both columns, where the separation resolution is always higher than 1.25 except for C1-C2 and C5-C6. Considering the pore size effect on the separation performance, it is shown that analytes, especially those with bigger size, display longer retention time in the column with larger pore size. For C10, the retention time in 5 nm-MS column is 200% longer than that in 2 nm-MS one.

Paeonol enhances the sensitivity of human ovarian cancer cells to radiotherapy-induced apoptosis due to downregulation of the phosphatidylinositol-3-kinase/Akt/phosphatase and tensin homolog pathway and inhibition of vascular endothelial growth factor.

Radiotherapy is a vital and effective method to treat solid tumors. However, in many tumor types, development of resistance of cancer cells and cytotoxicity in normal tissues presents a major therapeutic problem. It is therefore crucial to identify and develop novel sensitizing agents that may improve the response to radiation therapy without causing any adverse effects. The present study aimed to investigate whether paeonol, a bioactive flavonoid, was able to confer sensitivity to radiation in human ovarian cancer cells. The human ovarian cancer cell lines SKOV-3 and OVCAR-3 were exposed to varying doses of radiation (2, 4 or 6 Gy) in the presence or absence of paeonol (25, 50 or 100 µM). Radiosensitivity was assessed by measuring cell viability using a CCK-8 assay and Annexin V/PI staining. Expression of vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α), proteins of the phosphatidylinositol-3-kinase (PI3K)/Akt pathway and apoptotic pathway proteins [caspase-3, Bcl-2-associated death promoter, B-cell lymphoma (Bcl)-2, Bcl-2-associated X and Bcl-extra large (Bcl-xL)] were also assessed. Paeonol treatment enhanced apoptosis of SKOV-3 and OVCAR-3 cells that were exposed to radiation. The expression of Bcl-2 and Bcl-xL were markedly upregulated in these cells. Treatment with paeonol concentrations of 50 and 100 µM caused a significant downregulation of VEGF, HIF-1α and PI3K/Akt pathway proteins. Paeonol effectively enhanced the sensitivity of ovarian cancer cells to radiation by significantly altering regulation of the proteins of the PI3K/Akt pathway, in addition to downregulating VEGF and HIF-1α.

Degradation pathway and kinetics of 1-alkyl-3-methylimidazolium bromides oxidation in an ultrasonic nanoscale zero-valent iron/hydrogen peroxide system.

Fenton and Fenton-like oxidation has been already demonstrated to be efficient for the degradation of imidazolium ionic liquids (ILs), but little is known for their degradation pathway and kinetics in such systems. In this work, degradation pathway and kinetics of 1-alkyl-3-methylimidazolium bromides ([Cnmim]Br, n=2, 4, 6, 8, and 10) were investigated in an ultrasound nanoscale zero-valent iron/hydrogen peroxide (US-nZVI/H2O2) system. For this purpose, 1-butyl-3-methylimidazolium bromide ([C4mim]Br) was used as a representative ionic liquid to optimize pH value, nZVI dose, and H2O2 concentration for the degradation reaction. Then, the degradation kinetics of [Cnmim]Br was investigated under optimal conditions, and their degradation intermediates were monitored by gas chromatography-mass spectrometry (GC-MS). It was shown that the degradation of [Cnmim]Br in such a heterogeneous Fenton-like system could be described by a second order kinetic model, and a number of intermediate products were detected. Based on these intermediate products, detailed pathways were proposed for the degradation of [Cnmim]Br in the ultrasound-assisted nZVI/H2O2 system. These findings may be useful for the better understanding of degradation mechanism of the imidazolium ILs in aqueous solutions.

Identification of degradation products of ionic liquids in an ultrasound assisted zero-valent iron activated carbon micro-electrolysis system and their degradation mechanism.

Ionic liquids (ILs) have potential applications in many areas of chemical industry because of their unique properties. However, it has been shown that the ILs commonly used to date are toxic and not biodegradable in nature, thus development of efficient chemical methods for the degradation of ILs is imperative. In this work, degradation of imidazolium, piperidinium, pyrrolidinium and morpholinium based ILs in an ultrasound and zero-valent iron activated carbon (ZVI/AC) micro-electrolysis system was investigated, and some intermediates generated during the degradation were identified. It was found that more than 90% of 1-alkyl-3-methylimidazolium bromide ([Cnmim]Br, n = 2, 4, 6, 8, 10) could be degraded within 110 min, and three intermediates 1-alkyl-3-methyl-2,4,5-trioxoimidazolidine, 1-alkyl-3-methylurea and N-alkylformamide were detected. On the other hand, 1-butyl-1-methylpiperidinium bromide ([C4mpip]Br), 1-butyl-1-methylpyrrolidinium bromide ([C4mpyr]Br) and N-butyl-N-methylmorpholinium bromide ([C4mmor]Br) were also effectively degraded through the sequential oxidization into hydroxyl, carbonyl and carboxyl groups in different positions of the butyl side chain, and then the N-butyl side chain was broken to form the final products of N-methylpiperidinium, N-methylpyrrolidinium and N-methylmorpholinium, respectively. Based on these intermediate products, degradation pathways of these ILs were suggested. These findings may provide fundamental information on the assessment of the factors related to the environmental fate and environmental behavior of these commonly used ILs.