Self‐assembled thermo‐ and pH‐responsive poly(acrylic acid)‐b‐poly(N‐isopropylacrylamide) (PAA‐b‐PNIPAM) micelles for entrapment and release of doxorubicin (DOX) was described. Block copolymer PAA‐b‐PNIPAM associated into core‐shell micelles in aqueous solution with collapsed PNIPAM block or protonated PAA block as the core on changing temperature or pH. Complexation of DOX with PAA‐b‐PNIPAM triggered by the electrostatic interaction and release of DOX from the complexes due to the changing of pH or temperature were studied. Complex micelles incorporated with DOX exhibited pH‐responsive and thermoresponsive drug release profile. The release of DOX from micelles was suppressed at pH 7.2 and accelerated at pH 4.0 due to the protonation of carboxyl groups. Furthermore, the cumulative release of DOX from complex micelles was enhanced around LCST ascribed to the structure deformation of the micelles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5028–5035, 2008

Peptide amphiphiles are capable of self-assembly into a diverse array of nanostructures including ribbons, tubes, and vesicles. However, the ability to select the morphology of the resulting structure is not well developed. We examined the influence of systematic changes in the number and type of hydrophobic and hydrophilic amino acids on the self-assembly of amphiphilic peptides. Variations in the morphology of self-assembled peptides of the form X(6)K(n) (X = alanine, valine, or leucine; K = lysine; n = 1-5) are investigated using a combination of transmission electron microscopy and dynamic light scattering measurements. The secondary structures of the peptides are determined using circular dichroism. Self-assembly is controlled through a combination of interactions between the hydrophobic segments of the peptide molecules and repulsive forces between the charged segments. Increasing the hydrophobicity of the peptide by changing X to a more lipophilic amino acid or decreasing the number of hydrophilic amino acids transforms the self-assembled nanostructures from vesicles to tubes and ribbons. Changes in the hydrophobicity of the peptides are reflected in changes in the critical micelle concentration observed using pyrene probe fluorescence analysis. Self-assembled materials formed from cationic peptide amphiphiles of this type display promise as carriers for insoluble molecules or negatively charged nucleic acids in drug or gene delivery applications.

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Two tailor-made microporous metal-organic framework (MOF) membranes were successfully fabricated on nickel screens by secondary growth. The effect of pore structures on gas separation was examined by means of single and binary gas permeation tests. The MOF JUC-150 membrane with its ultramicropores showed marked preferential permeance to H 2 relative to other gas molecules. The selectivity factors of this membrane were 26.3, 17.1 and 38.7 for H 2 /CH 4 , H 2 /N 2 and H 2 /CO 2 , respectively, at room temperature. To the best of our knowledge, these values represent unprecedentedly high separation selectivity among those for all MOF membranes reported to date. The JUC-150 membrane also shows high thermal stability and outstanding separation performance at a high temperature of 200 C. The separation performance of these membranes persists even after more than 1 year exposure to air. The superiority of the tailored pore size, high selectivity for H 2 over other gases, significant stability and recyclability make these materials potential candidates for industrial H 2 recycling applications. Broader contextHydrogen provides reliable, sustainable, environmentally and climate-friendly energy that meets the world's energy requirements through a high energy density. It usually coexists with other light gases (CO 2 , CH 4 , N 2 , etc.) during production from industrial processes such as gasication or steam reforming reactions. To make better use of these hydrogen-rich streams as fuels, hydrogen must be separated from the mixtures. To achieve this goal of high-purity hydrogen, new technologies are needed. Membrane separations require less energy than distillation or liquefaction, use less space than absorbent materials, and operate in a continuous mode. Here, we report two tailor-made microporous metal-organic framework (MOF) membranes fabricated on nickel screens by secondary growth. Through the process of pore size adjusting, the JUC-150 membrane represents unprecedentedly high separation selectivity among those for all MOF membranes reported to date. The performance of the JUC-150 membrane is also outstanding at the high temperature (200 C). The superiority of the tailored pore size, high selectivity for H 2 over other gases, signicant stability and recyclability make these materials potential candidates for industrial H 2 recycling applications.

ACE technique provides an effective tool for the separation and identification of disease-related biomarkers in clinical analysis. In recent years, a couple of synthetic DNA or RNA oligonucleotides, known as aptamers, rival the specificity and affinity for targets to antibodies and are employed as one kind of powerful affinity probe in ACE. In this work, based on high affinity between antithrombin aptamer and thrombin (their dissociation constant is 0.5 nM), a carboxyfluorescein-labeled 29-nucleotide (nt) aptamer (F29-mer) was used and an aptamer-based affinity probe CE (aptamer-based APCE) method was successfully established for high-sensitive detection and quantitative analysis of thrombin. Experimental conditions including incubation temperature and time, buffer composition, and concentration of cations were investigated and optimized. Under the optimized condition, the linear range was from 0 to 400 nM and the LOD was 2 nM (74 ng/mL, S/N = 3), i.e., 40 amol, both in running buffer and in 5% v/v human serum. This LOD is the lowest one than those achieved by the previous APCE methods but based on a 15-mer aptamer. This approach offers a promising method for the rapid, selective, and sensitive detection of thrombin in practical utility. Further binding experiments using one carboxyfluorescein-labeled aptamer and the other nonlabeled aptamer or vice versa were carried out to deduce the formation of ternary complex when these two aptamers coexisted in the free solution with thrombin.

A homochiral MOF membrane was successfully and facilely synthesized using an in situ growth method, which had the advantages of cheap raw materials, simple operation and high thermal stability. A diol isomer mixture was used to test the separation efficiency of the membrane at different temperatures and pressures.

In one event, Chinese male individuals accidentally exposed to unknown chemicals and emerged erythema or blisters on contacted organism derma, then hospitalized. To identify the causative agents, blood, urine and exudate samples were collected from the patients during the therapeutic course. Five established liquid chromatography–mass spectrometry (LC–MS) and gas chromatography (GC)–MS methods were employed to analyze the samples. Here, an overall analysis of four types of sulfur mustard biomarkers, including the hydrolysis/oxidation products, β-lyase metabolites, DNA adducts and hemoglobin adducts, was conducted toward the samples from exposed individuals. The results of all the four types of biomarkers in different biomedical matrices showed high relevance, and verified that this exposure is indeed originated from sulfur mustard. The concentrations of the biomarkers in specimens revealed a good correlation with the severity of the patient's symptom. The concentration-time profile demonstrated that most of the biomarkers quickly achieved maximum at the beginning of the course, and then decreased and kept a detectable level until the 7th day after exposure. The DNA adducts in urine samples still appeared on the 30th day, and the N-terminal valine adducts in hemoglobin could be monitored for over 90 days, which was meaningful for the concurrent study of clinical samples. To the best of our knowledge, this work provides the total analysis and profile of four categories of biomarkers in human specimens for the first time, and the good accordance between concentration and level of burns, between time course and biomarkers will be of great importance for early diagnosis and medical treatment monitoring of sulfur mustard exposure.

Sulfur mustard (SM) is a highly reactive alkylating vesicant and causes blisters upon contact with skin, eyes, and respiratory organs. It covalently links with DNAs by forming four mono- or cross-link adducts. In this article, the reference standards of SM-DNA adducts and deuterated analogues were first synthesized with simplified procedures containing only one or two steps and using less toxic chemical 2-(2-chloroethylthio)ethanol or nontoxic chemical thiodiglycol as starting materials. A sensitive and high-throughput simultaneous quantification method of N(7)-[2-[(2-hydroxyethyl)thio]-ethyl]guanine (N(7)-HETEG), O(6)-[2-[(2-hydroxyethyl)thio]-ethyl]guanine (O(6)-HETEG), N(3)-[2-[(2-hydroxyethyl)thio]-ethyl]adenine (N(3)-HETEA), and bis[2-(guanin-7-yl)ethyl]sulfide (Bis-G) in the Sprague-Dawley rat derma samples was developed by stable isotope dilution-ultrahigh performance liquid chromatography-tandem mass spectrometry (ID-UPLC-MS/MS) with the aim of revealing the real metabolic behaviors of four adducts. The method was validated, the limit of detection (S/N ratio greater than 10) was 0.01, 0.002, 0.04, and 0.11 fmol on column for N(7)-HETEG, O(6)-HETEG, Bis-G, and N(3)-HETEA, respectively, and the lower limit of quantification (S/N ratio greater than 20) was 0.04, 0.01, 0.12, and 0.33 fmol on column for N(7)-HETEG, O(6)-HETEG, Bis-G, and N(3)-HETEA, respectively. The accuracy of this method was determined to be 76% to 129% (n = 3), and both the interday (n = 6) and intraday (n = 7) precisions were less than 10%. The method was further applied for the quantifications of four adducts in the derma of adult male Sprague-Dawley rats exposed to SM ex vivo and in vivo, and all adducts had time- and dose-effect relationships. To the best of our knowledge, this is the first time that the real presented status of four DNA adducts was simultaneously revealed by the MS-based method, in which Bis-G showed much higher abundance than the result previously reported and N(3)-HETEA showed much less. It should be noted that since the interstrand cross-linked adduct is believed to stall DNA replication and finally induce a double-strand break, the higher abundance of Bis-G is a great indication of a more serious DNA lesion by SM alkylation.