Adsorption behavior of urokinase by polypropylene film modified with amino acids as affinity groups

In order to prepare a new-type adsorbent with an affinity ligand, polypropylene films modified with amino acid groups such as -phenylalanine (Phe), , -Phe, -cysteine (Cys), and , -tryptophane (Try), were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) films and subsequent amination of poly-GMA graft chains. The physical and chemical properties of the GMA-grafted PP film and the PP film modified with amino acid groups were investigated by IR and XPS. The adsorption of urokinase for the PP films modified with four kinds of amino acid groups were examined under various conditions, such as the contents of the amino acid group and pH value. The adsorption of urokinase increased with the increasing content of the amino acid group. The adsorption of the PP film modified with four kinds of amino acid groups was in the following order: -Phe> , -Phe> , -Try> -Cys. The adsorption amounts of urokinase by the PP film modified with four kinds of amino acid groups at pH 7.4 was higher than that at pH 9.0.     

多功能氨基酸衍生物钝化的高性能钙钛矿太阳能电池

采用含有羧基、氨基和苯基等多官能团的氨基酸衍生物分子(Fmoc-L-异亮氨酸,Fmoc-Ile-OH)钝化钙钛矿薄膜表面缺陷。首先,该氨基酸衍生物可降低钙钛矿薄膜中PbI₂杂质含量,并提高钙钛矿薄膜的颗粒尺寸。其次,氨基酸衍生物的引入可有效改善钙钛矿薄膜的光学特性和钙钛矿/电荷传输层界面载流子输运性能。另外,经钝化处理的钙钛矿太阳能电池表现出更优的器件二极管理想因子、更低的陷阱填充极限电压和更高的载流子复合电阻,这些结果证实了Fmoc-Ile-OH可有效钝化钙钛矿薄膜表面缺陷。最后,通过工艺条件优化,制得了转化效率为21.09%的高效钙钛矿太阳能电池器件,其性能远优于对照组器件的效率(18.00%)。     

Synthesis of end‐functionalized AB copolymers. II. Synthesis and characterization of carboxyl‐terminated poly(ethylene glycol)–poly(amino acid) block copolymers

AB block copolymers composed of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(amino acid) with a carboxyl group at the end of PEG were synthesized with α‐carboxylic sodium‐ω‐amino‐PEG as a macroinitiator for the ring‐opening polymerization of N‐carboxy anhydride. Characterizations by ¹H NMR, IR, and gel permeation chromatography were carried out to confirm that the diblock copolymers were formed. In aqueous media this copolymer formed self‐associated polymer micelles that have a carboxyl group on the surface. The carboxyl groups located at the outer shell of the polymeric micelle were expected to combine with ligands to target specific cell populations. The diameter of the polymer micelles was in the range of 30–80 nm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3527–3536, 2004     

Interaction forces between metal-chelating lipid monolayers measured by colloidal probe atomic force microscopy

Surface forces between LB films of metal-chelating lipids in water have been studied using colloidal probe atomic force microscopy. The LB films of an amphiphile functionalized by the iminodiacetic acid group were prepared on hydrophobic glass substrates. The electric double layer repulsion operated between these LB film surfaces changed depending on pH reflecting the different protonation states of the iminodiacetic acid groups. The titration curve of the iminodiacetic acid monolayer was obtained from the force profiles. The Cu²⁺ complexation process was also monitored by measuring the force profiles at various Cu²⁺ ion concentrations.     

Structures and gas-sorption properties of carbonaceous film prepared by radio-frequency sputtering of polysaccharides pectin

Carbonaceous films with microcolumnar layer have been prepared by radio-frequency sputtering of polysaccharides pectin. The repeated sputtering has developed the densely packed seamless microcolumns, which are separated by the narrow grooves. The residual film stress has formed the honeycomb-patterned ridges. X-ray photoelectron spectroscopy and energy dispersion spectroscopy revealed the inclusion of nitrogen in the film constituents. The film surface is hydrophilic mainly due to the polar functional groups, such as the carboxyl and amino groups. Nitrogen adsorption measurement revealed that the specific surface area of the film was no less than 109 m²/g. Impedance analysis of the film-coated quartz crystal resonator clarified that the film had the higher adsorption capacities to the polar and cohesive vapors, such as ethyl alcohol. The adsorption of organic vapors has not induced the viscoelastic changes in the film.     

Preparation of a bacterial polyester with carboxy groups in side chains

Unsaturated biopolyesters were produced by Pseudomonas oleovorans from two mixtures of sodium octanoate and 10-undecenoic acid (90:10 and 80:20 mol/mol) as a reserve of carbon and energy. Chemical modification of double bonds into carboxyl groups was carried out with potassium permanganate (KMnO₄). Oxidation reaction was proved by ¹H and ¹³C NMR spectroscopy. Molecular weights of modified biopolyesters were not highly affected by the oxidation reaction. Hydrophilicity was enhanced; polyester containing 25 % of repeating units pendant carboxylic acid end groups was soluble in polar solvents such as methanol, dimethylsulfoxide or a 85:15 (v/v) acetone/water mixture. Moreover, the presence of carboxy pendant groups was important with respect to the hydrolytic degradation. A fast hydrolysis was observed at pH = 11 in 24 hours for the carboxylated modified polyester containing 25 % of carboxyl groups.     

Synthesis of photocrosslinkable hyperbranched polyesters and their film properties

Hyperbranched polyesters with terminal methacryloyl groups (HBPEAc) were synthesized by the one‐pot polyaddition of bisphenol A diglycidyl ether and trimesic acid in the presence of methacrylic acid with a number‐average molecular weights of 5100–7700 in 70–83% yields. The photoradical polymerization of HBPEAc was examined in the presence of 2‐methyl‐1‐[4‐(methylthio)phenyl]‐2‐morpholinopropan‐2‐one (Irgacure 907®) as a photoinitiator in the film state upon UV irradiation to afford the corresponding cured films quantitatively. The crosslinking densities of the cured films of HBPEAc were higher than those of the corresponding linear ones, and birefringence cannot be detected for the cured films of HBPEAc because of their random structures. Furthermore, an alkaline‐developable hyperbranched polyester containing pendant carboxyl groups (HBPEAc‐COOH) was prepared by the addition reaction of HBPEAc with cis‐1,2,3,6‐tetrahydrophthalic anhydride, and its patterning properties were examined to give the resolution of a 55‐μm‐line and 275‐μm‐space pattern by UV irradiation with 700 mJ/cm². © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4642–4653, 2005     

Preparation of Polylactide Microspheres Having Positively or Negatively Charged Surfaces

The syntheses of polylactides (PLAs) with branched peptide end groups containing reactive (ionic) moieties such as amino or carboxyl groups are described and were used to prepare PLA‐based microspheres (MSs) with positively or negatively charged surfaces. Branched peptides with hydroxyl end groups and four protected amino or carboxyl groups, Boc₄‐K₃‐OH or Bn₄‐E₃‐OH, were synthesized, and the hydroxyl group converted to an alkoxide and was used as the initiation site for the ring‐opening polymerization of L ‐lactide. Subsequent deprotection gave PLAs end‐capped with branched peptides having four amino or carboxyl groups, respectively (K₃‐PLA and E₃‐PLA). K₃‐PLA and E₃‐PLA were converted to K₃⁴⁺‐PLA and E₃^4?‐PLA by acid or base treatment, respectively. MSs with charged surfaces were then prepared using K₃⁴⁺‐PLA or E₃^4?‐PLA as a surfactant [MS(K₃⁴⁺‐PLA) or MS(E₃^4?‐PLA)]. The ionic surface state of the MSs was confirmed by colloidal titration and zeta potential analysis.

SEM image of MSs: MS(K₃⁴⁺‐PLA).     

Solubility enhancement for poly(amic acid)s by rapid hydrolysis of the polymer main chain during alkaline development

In an alkaline developer carboxyl containing polymer films possess a higher critical carboxyl group concentration (CGC₀) below which dissolution does not occur, compared with novolac resins; therefore, it is difficult to obtain the polymer film with a lower dissolution rate and less swelling. We describe herein a new approach for reducing CGC₀ of carboxyl containing polymers by introducing an ester group which is labile in the alkaline developer within the time‐scale of development to obtain the polymers with moderate dissolution rates and less swelling. The rapid hydrolysis that leads to polymer degradation is clearly verified by gel permeation chromatography (GPC).     

FT–IR spectroscopic study on the photo- and photooxidative degradation of nylons

The progress of photo- and photooxidative degradation of nylon films were studied by FT–IR spectroscopy. The gases evolved from the photolysis of various nylons and their model amides were also analyzed. The formation of double bonds, changes of crystallinity, and the effect of amino and carboxyl end groups has been studied and discussed. The band shapes of the IR spectra pertaining to the carbonyl groups formed by thermal oxidation or photooxidation were found to be very similar, suggesting that the two oxidation mechanisms might be similar. The broadness of these bands indicates that the carbonyl groups may belong to more than one species. The photodegradation of nylons containing purposely inserted carbonyl groups formed ? CH?CH₂ groups. Carbonyl groups formed during oxidation, and present either as keto groups or part of N-acylamide units make nylons susceptible to degradation reactions entailing mainly a Norrish type II mechanism.     

Biodetergent IV. Monolayers of corynomycolic acids at the air-water interface

The effects of alkyl chain length and of differences in the length of the two alkyl chains on the formation of a monolayer of chemically synthesized corynomycolic acid (2-alkyl-3-hydroxy fatty acid) at the air-water interface were examined. Hydrophobic interactions between the two alkyl chains are required for the formation of a condensed film, which is most stable when the total number of carbon atoms in the two alkyl chains is 25 or more and the difference in their lengths is one. Syn-isomers form condensed films but usually not anti-isomers. However, films may also be formed by the anti-isomer when the alkyl chain at the carboxy group (the 2-position) is longer than the alkyl chain at the hydroxy group (the 3-position). That is, the contribution of anti-isomers to condensed film formation depends on the polar carboxy group which has greater involvement in this formation. The extrapolated area for the condensed film of corynomycolic acid was 40 Ų per molecule, thus confirming that both the carboxy and hydroxy groups are present on the water surface when a bipolar monolayer is formed.     

Self-Assembly Behavior of Diacetylenic Acid Molecules upon Vapor Deposition: Odd–Even Effect on the Film Morphology

A series of linear carboxylic acids containing diacetylenic units at different positions along the chain (C₁₂H₂₅(C≡C)₂(CH₂)_nCOOH, n=7–11) were vacuum-deposited on clean silica substrates. The morphologies of the initial films after UV irradiation were studied. A clear odd–even effect on the morphology of the initial film was observed in that, depending on the spacer length between the diacetylenic unit and carboxyl head group, rings or dendrites of acid dimer layers were obtained. A molecular dynamic simulation of the aggregation process suggests that two competing intermolecular interactions and thus aggregation directions are involved and modulated by the odd or even carbon chain length. Further modulation of the interaction by substitution of a phenyl group at the terminus of the chain or by changing the carboxyl head group to an amidobenzoic acid head group led to a similar odd–even effect but with different dimensions or trends, which can be rationalized similarly. These results give the opportunity to create aligned conjugated polymer chains of different dimensions through self-assembly for applications in molecular/organic electronics.     

Chemical structure of polycaproamide obtained by anionic polymerization of caprolactam in solvent

Chemical structure of polycaproamide (nylon-6), obtained by low temperature anionic polymerization of caprolactam in the presence of the sodium salt of caprolactam and carbon dioxide in solvent has been investigated. The polymer formed in a heterogeneous system, depending upon its final treatment, is terminated with amino and cyclic lactam groups or, after hydrolysis, with amino and carboxyl group. i.r. Spectra and acid-base titrations have shown the presence of amino and carboxyl groups in macromolecules. The contents of basic and acidic groups in the final product and its fractions were determined by potentiometric titrations. Number-average molecular weights of samples based on the results of titrations were compared with the results of osmotic measurements. Equal numbers of basic and acid groups in the polymer suggests that macromolecules are terminated at one end by an amino group and at the other by a carboxyl group. The results indicate a linear and regular structure for the polycaproamide.     

Determination of end groups as a function of molecular size for aliphatic polyesters by derivatization of end groups and size-exclusion chromatography with infrared detection

End groups of poly(ethyleneglycol sebacate) having number average molecular weights less than 2500 were characterized as a function of molecular size by derivatizing end groups separately to form 3,5-dinitrobenzoyl and p-nitrobenzyl esters. A hydroxyl end group was reacted with 3,5-dinitrobenzoyl chloride (DNBC) and a carboxyl end group was reacted with O-(p-nitrobenzyl)-N,N′-diisopropyl isourea (PNBD). After separation of these derivatized polyesters by size-exclusion chromatography, the effluent was monitored by using a highly sensitive infrared detector. Concentrations of polyesters were monitored at 1740 cm^?1 for a carbonyl group in the main chain, polyesters derivatized with DNBC at 1560 cm^?1 for a hydroxyl end group (characteristic absorption band for the nitro group of DNBC), and polyesters derivatized with PNDB at 1537 cm^? for a carboxyl end group (a characteristic absorption band for the nitro group of PNBD). By this technique, three types of polyesters having different end groups were characterized: a diol-type polyester, a mixture of polyesters of a diol type and a mono-ol/monocarboxyl type, and a mixture of polyesters of a dicarboxyl type a mono-ol/monocarboxyl type.     

Studies on some radical transfer reactions by entrapping the radicals as polymer end groups. II. Reactions of ȮH radicals with amino acids

The reaction of ?H radicals with a number of aliphatic amino acids has been studied by entrapping the resultant radicals as end groups of poly(methyl methacrylate) that have been detected and estimated by the sensitive dye partition technique. The rate constants of the reaction (in mol^?1 L S^?1) of 7 amino acids at 25°C and at pH 1.00 have been determined as 8.33 × 10⁸ for glycine, 2.56 × 10⁹ for β-alanine, 2.01 × 10⁹ for β-alanine, 3.99 × 10⁹ for 4-amino butyric acid, 7.56 × 10⁹ for (1+) valine, 1.42 × 10¹⁰ for (1?) leucine, and 5.98 × 10¹⁰ for 6-amino caproic acid. Glycine, α-alanine, β-alanine, and 4-amino butyric acid produced radicals that underwent deamination and incorporated only carboxyl-bearing end groups in the polymer. The other amino acids, leucine, valine, and 6-amino caproic acid, produced at least two types of radicals, radicals that underwent deamination and those that remained intact, and incorporated in the polymer both carboxyl- and amine-bearing end groups but in different amounts. The latter type of radicals were about 29% from 6-amino caproic acid, 23% from leucine, and 18% from valine. The change of pH from 0.80 to 2.72 did not produce any significant change in the end group profile of the polymer obtained, indicating no appreciable change in the rate of the reaction of ?H radicals with the simplest amino acid glycine in the pH range studied.     

Chiral poly(amide-imide)/organoclay nanocomposites derived from pyromellitoyl-bis-l-isoleucine and benzimidazole containing diamine: synthesis, nanostructure, and properties

In this study, a series of polymer–clay nanocomposite materials, consisting of organosoluble poly(amide-imide) (PAI) matrix and dispersed nanolayers of inorganic montmorillonite clay, were successfully prepared by solution dispersion technique. At first, the reactive organoclay was prepared by using protonated l-isoleucine amino acid as a swelling agent for silicate layers of Cloisite Na⁺. Then, organosoluble PAI containing isoleucine amino acid was synthesized through step-growth polymerization reaction of N,N′-(pyromellitoyl)-bis-isoleucine diacid and 2-(3,5-diaminophenyl)-benzimidazole under green condition using molten tetrabutylammonium bromide. This polymer was end-capped with amine end groups near the completion of the reaction to interact chemically with acidic group of organoclay. Finally, PAI/organoclay nanocomposite films containing 2%, 5%, 10%, and 15% of organoclay were prepared via solution intercalation method through blending of organoclay with the PAI solution. Dispersion of the modified clay in the PAI matrix resulted in a nanostructured material containing intercalated polymer between the silicate layers. Structures of exfoliation were confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. Thermogravimetric analysis data indicated that the addition of organoclay into the PAI matrix increased the thermal decomposition temperatures of the obtained nanocomposites compared to the pure PAI.     

Synthesis and surface characterization of heparin-immobilized polyetherurethanes

Novel poly(ether urethanes) containing diester groups in the side chains (PU) were synthesized from 4,4′-diphenylmethyl diisocyanate, polytetramethylene glycol, and diethyl bis(hydroxymethyl)malonate as a chain extender. The surface modification of the PU film was carried out by a hydrolysis reaction, poly(ethylene oxide) (PEO) grafting, and heparin immobilization, and the surface-modified PUs were then characterized by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, electron spectroscopy for chemical analysis (ESCA), and a contact angle goniometer. The concentration of carboxylic acid groups introduced on the PU surfaces as determined by the rhodamine interaction method was 61 nmol/cm² when treated with 4N NaOH/methanol (1 : 2 v/v) for 30 min and subsequently with a citric acid–methanolic aqueous solution. The amounts of heparin coupled to the carboxyl groups on the PU surfaces and to the terminus amino groups on the PU-PEO were 0.92 and 0.84 μ g/cm², respectively. There was almost no heparin released from the immobilized surface of a physiological solution for 100 h, thereby indicating the strong stability of immobilized heparin. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2331–2338, 1998     

Synthesis of dicarboxylate oligosaccharide multilayer terminal functionality upon poly(lysine) dendrimer scaffolding

A reactive three‐layered dendrimer containing carboxyl groups was synthesized by the coupling of dicarboxylic acid and a highly reactive, two‐layered glycopeptide dendrimer. Lactose, maltose, or maltotriose was reacted with the poly(lysine) dendrimer in its third and fourth generations by reductive amination and afforded two‐layered glycolysine dendrimers. The reaction was conducted in a borate buffer (pH 9.0). ¹H NMR, ¹³C NMR, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analyses were applied for the determination of the structures of the products. When an excess amount of the oligosaccharide and a long reaction time were used, the degree of substitution increased to 1.5–2.0 against an amino group. For the preparation of highly reactive, multilayered dendrimers for an antigen carrier, C6 hydroxy groups of the oligosaccharides were selectively esterified by adipic acid and suberic acid to give 6‐O‐adipoyl oligosaccharide–poly(lysine) dendrimers and 6‐O‐suberoyl oligosaccharide–poly(lysine) dendrimers. The reactivity of these multilayered dendrimers was examined by a model reaction with phenylalanine ethyl ester. The dendrimer showed high reactivity, providing phenylalanine ethyl ester–dicarboxylate oligosaccharide–poly(lysine) dendrimers with a considerably high proportion of phenylalanine residues. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3622–3633, 2002     

SYNTHESIS OF CONDENSATION POLYMERS OF SALICYLIC ACID, FORMALDEHYDE AND ALKYL PRIMARY AMINES AND ITS APPLICATION AS A CATALYST FOR THE HYDROLYSIS OF p-NITROPHENYL ACETATE (PNPA) IN AQUEOUS SOLUTION

As a model of serine hydrolase, the condensation polymers of salicylic acid, formaldehyde and methyl amine, n-propyl amine, n-hexyl amine or n-lauryl amine were prepared by polycondensation catalyzed by sulfuric acid. It was confirmed by potentiometric titration and infrared spectrum that the polymers containing tertiary amino group possess the structure which resembles the internal salt of amino acid in weak basic and weak acidic solution:     

Functionalization of Poly[Ethylene Terephthalate) by Means of Glow-Discharge-Initiated Polymerization of Acrylic Acid

Glow-discharge-initiated polymerization of acrylic acid incorporated in poly(ethylene terephthalate) (PET) films was investigated. An increase in polymerization yield with plasma treatment duration and power was found. Polymerization was not confined to the film surface. At high power and long treatment time, polymerization in the bulk of the PET also took place. Water regain and contact angle of the PET-treated films were affected by the presence of poly(acrylic acid) (PAA). The carboxyl groups of the PAA chains incorporated in the PET matrix were utilized for further chemical modification of the PET film. Poly(ethylene glycol) (PEG) was grafted onto PAA by esterification. DSC studies showed the presence of both PAA and PEG in the PET matrix and shed light on the morphology of the multicomponent polymeric system. Free isocyanate groups were introduced into the PET matrix by reacting PAA carboxyl groups with hexamethylene diisocyanate.