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Background: Scaffold-based gene therapy provides a promising approach for tissue engineering, which was important and popular as it combined medical applications and engineering materials’ knowledge. Objective: The decellularization techniques were employed to remove the cellular components from porcine elastic cartilages, leaving a native decellularized Extracellular Matrix (dECM) composition and architecture integrity of largely insoluble collagen, elastin, and tightly bound glycosaminoglycans. For newly designed collagen scaffold samples, elastic cartilages were hydrolyzed by protease with different concentrations to gain state completely and clearly. Methods: An extraction process of Supercritical Carbon Dioxide (ScCO2) was used to remove cellular components from porcine elastic cartilage. The dECM scaffolds with collagen must be characterized by Fourier transform infrared spectroscopy(FTIR), Thermo-Gravimetric Analysis (TGA), and Scanning Electron Microscope (SEM). Results: The study provided a new treatment combined with supercritical carbon dioxide and alkaline/ protease to prepare dECM scaffolds with hole-scaffold microstructures and introduce into a potential application on osteochondral tissue engineering using scaffold-based gene therapy. The new process is simple and efficient. The pore-scaffold microstructures were observed in dECM scaffolds derived from porcine elastic cartilages. The Tdmax values of the resulting dECM scaffolds were observed at over 330oC. Conclusion: A series of new scaffolds were successfully obtained from porcine tissue by using ScCO2 and alkaline/enzyme treatments such as a mixing aqueous solution of NH4OH and papain. The dECM scaffolds with high thermal stability were obtained. The resulting scaffold with clean pore-scaffold microstructure could be a potential application for scaffold-based gene therapy.

Metabolites are the essential substrates for epigenetic modification enzymes to write or erase the epigenetic blueprint in cells. Hence, the availability of nutrients and activity of metabolic pathways strongly influence the enzymatic function. Recent studies have shed light on the choreography between metabolome and epigenome in the control of immune cell differentiation and function, with a major focus on histone modifications. Yet, despite its importance in gene regulation, DNA methylation and its relationship with metabolism is relatively unclear. In this review, we will describe how the metabolic flux can influence epigenetic networks in innate and adaptive immune cells, with a focus on the DNA methylation cycle and the metabolites S‐adenosylmethionine and α‐ketoglutarate. Future directions will be discussed for this rapidly emerging field.

BACKGROUND: The biologic scaffolds derived from decellularized tissues and organs have been successfully developed in a variety of preclinical and/or clinical studies. OBJECTIVE: The new decellularized liver-regenerative 3D printing biomaterials were designed and prepared for cell-based liver therapies. METHODS: An extraction process was employed to remove the tissue and cellular molecules from porcine liver via pretreatment of supercritical fluid of carbon dioxide (ScCO2). Varying porosities of the decellularized liver tissues were created using papain-containing reagent treatments after ScCO2. RESULTS: The resulting liver-regenerative 3D printing biomaterials of decellularized liver collagen scaffolds were characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, differential scanning calorimetry and scanning electron microscopy. CONCLUSIONS: The decellularized liver collagen scaffolds with good thermal stability (>150 °C) were obtained and employed as liver-regenerative 3D printing biomaterials for cell-based liver therapies.

Curcumin is a natural active constituent with a great variety of beneficial biological and pharmacological activities, is a practically water-insoluble component. The scope of the present work was to prepare a solid dispersion (SD) formulation to enhance the dissolution rate of curcumin. The SD was prepared using curcumin and β-cyclodextrin (CD)/HA via a classical ethanol-based solvent evaporation method. The as-prepared β-CD/HA and SDs were selectively characterised by various analytical techniques including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, specific surface area/pore size analysis, Fourier transform infrared spectroscopy, and high-performance liquid chromatography. According to the dissolution tests, it was confirmed that β-CD/HA–curcumin SD can significantly enhance the dissolution of curcumin. In addition, an increasing trend was seen between the β-CD weight ratio and the dissolution rate of curcumin, and β-CD/HA–curcumin (9:1) SD was shown to be the best formulation among all tested samples with over 90% curcumin dissolved in 180 min. Besides, β-CD/HA–curcumin (9:1) SD exhibited pH and medium-dependent curcumin release behaviours. The antioxidant activity of released curcumin showed no difference to original curcumin. These results clearly demonstrated β-CD/HA can be a promising SD carrier to improve the dissolution of curcumin.

For patients with extensive full-thickness burns who do not have sufficient autologous split-thickness skin for skin grafts, the application of biological skin substitutes may be considered. The aim of this study was to find an optimal new type method for the production of a biovital skin substitute based on acellular dermal matrix (ADM) and preclinical evaluations. In this work, 25 methods of ADM production were assessed. The proposed methods are based on the use of the following enzymes: papain, Carica papaya lipase (CPL), and purification using a polymer/salt aqueous two-phase system. The obtained ADM samples were characterized via scanning electron microscopy (SEM), porosity measurement and water vapor transmission test. Results showed that the collagen bundles of ADM microparticles were intact and orderly. Through differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and biocompatibility tests, the results indicated that the proportion of papain and CPL was the same and 5 h processing time are the optimum conditions for ADM preparation and the material showed good biocompatibility. Our results suggested that the potential of developing this kind of decellularization process to manufacture ADM scaffolds for clinical application.

This study was aimed to develop the new transdermal formulation to improve the permeability of buprenorphine. The apparent partition coefficients of buprenorphine were measured using the buffers at pH 1.2 to 10.0 as aqueous phase. The solubility of buprenorphine was 12.97 μg/mL in the 0.1 M phosphate buffer at pH 6.8. The influences of vehicles at different pH, adhesives, and permeation enhancers on the penetration of buprenorphine through nude mouse skin were investigated using the static Franz diffusion cells. The permeation parameter J(subscript ss) of buprenorphine increased along with the reduction of the pH of receptor fluid, and the vehicle at pH 6.8 was used in the following skin permeation studies. The pressure sensitive adhesives (PSA) including polyisobutylene (PIB), polystyrene-block-polyisoprene-block-polystyrene (SIS), and acrylic adhesives were evaluated. The permeability of buprenorphine was higher in the PIB or SIS adhesives than that in the acrylic adhesives under the condition without enhancer. When combined the enhancers with propylene glycol (PG) to improve the penetration of buprenorphine, the permeation-enhancing effects of enhancers were in the following order: lauric acid ＞ linolenic acid ＞ menthol ＞ oleic acid ＞ N-methyl-2-pyrrolidone (NMP) ＞ laurocapram ＞ glabridin. Finally, a matrix-type transdermal delivery system for buprenorphine was formulated using acrylic adhesive, PG, and lauric acid. The Jss parameter was 2.68±0.20 μg/cm^2/h and buprenorphine permeated across the nude mouse skin was 31.68%.

The design of medical devices could be applied and developed for new treatment procedures instead of the traditional therapy procedures...

Tissue-engineering was important which combine medical applications and engineering materials. A extraction process was employed to remove the tissue and cellular molecules from porcine costal cartilages in this study via pretreatment of supercritical fluid of carbon dioxide. Varying porosities of the decellularized tissues were then created using papain-containing reagent treatments. The author studied characterizations of the designed decellularized scaffolds derived from porcine costal cartilages via supercritical fluid and papain-containing reagent treatments.

The design of medical devices could be applied and developed for new treatment proce-dures instead of the traditional therapy procedures.

The design of medical devices could be applied and developed for new microscopic surgical procedures instead of the traditional surgical procedures.

Numerous consumer products, such as cosmetics, contain nanoparticles (NPs) of titanium dioxide (TiO2) or zinc oxide (ZnO); however, this raises questions concerning the safety of such additives. Most of these products do not indicate whether the product includes NPs. In this study, we characterized metal oxide NPs according to size, shape, and composition as well as their aggregation/agglomeration characteristics. In order to comprehend quickly the characterization of metal oxide NPs, we employed single particle inductively coupled plasma (SP-ICPMS) to help quantify the size of metal oxide NPs; then, we use transmission electron microscopy (TEM) to corroborate the results. The crystal size and structure was measured by X-ray diffraction (XRD), there are two crystal phase of TiO2 NPs in sunscreen powder showed in XRD. However, SP-ICPMS proved highly effective in determining the size of NPs, the results of which remarkably good agreement with the TEM measurements. Pre-treatment included a conventional copper grid (requiring sample dilution) to evaluate the size, shape and composition of primary particles or plastic embedding (without the need for sample dilution) to evaluate the aggregate/aggregation of native NOAAs. The proposed method is an effective and fast approach to the characterization of oxide NPs in cosmetic sunscreen powder. These findings outline an alternative approach to the analysis of NPs in powder-form matrix. Keywords: Sunscreen powder, Nanoparticles, Titanium dioxide, Zinc oxide, Single particle inductively coupled plasma

A series of designed drug-release systems were prepared and established for clear moisture healing. These systems were designed to have an interpenetrating polymer network (IPN) structure, which contained a breathable polyurethane film, hydrocolloidlayer, and polyacrylate adhesive layer. Breathable polyurethane film (2000 g/m(2)/24 hr) with high moisture permeability was employed as a base for new drug-release systems or wound dressings. All drug-release systems having a polyurethane film-backed hydrocolloid acrylated adhesive layer showed an increase of water uptakes with increasing time. After 114 hours, high water uptakes of drug-release systems with 20% hydrocolloid components were observed in the values of 160, 1100, and 1870% for different additional hydrocolloid components of carboxymethylcellulose, sodium alginate, and carbomer U10, respectively. New drug-release systems of polyurethane film-backed hydrocolloid/adhesive layers could be designed and established for wound care managements.

A characteristic of memory T (T M ) cells is their ability to mount faster and stronger responses to reinfection than naïve T (T N ) cells do in response to an initial infection. However, the mechanisms that allow this rapid recall are not completely understood. We found that CD8 T M cells have more mitochondrial mass than CD8 T N cells and, that upon activation, the resulting secondary effector T (T E ) cells proliferate more quickly, produce more cytokines, and maintain greater ATP levels than primary effector T cells. We also found that after activation, T M cells increase oxidative phosphorylation and aerobic glycolysis and sustain this increase to a greater extent than T N cells, suggesting that greater mitochondrial mass in T M cells not only promotes oxidative capacity, but also glycolytic capacity. We show that mitochondrial ATP is essential for the rapid induction of glycolysis in response to activation and the initiation of proliferation of both T N and T M cells. We also found that fatty acid oxidation is needed for T M cells to rapidly respond upon restimulation. Finally, we show that dissociation of the glycolysis enzyme hexokinase from mitochondria impairs proliferation and blocks the rapid induction of glycolysis upon T-cell receptor stimulation in T M cells. Our results demonstrate that greater mitochondrial mass endows T M cells with a bioenergetic advantage that underlies their ability to rapidly recall in response to reinfection.

Developmentally arrested infective larvae of strongylid nematodes are activated to resume growth by host-derived cues encountered during invasion of the mammalian host. Exposure of Nippostrongylus brasiliensis infective larvae to elevated temperature (37 °C) is sufficient to activate signalling pathways which result in resumption of feeding and protein secretion. This occurs independently of exposure to serum or glutathione, in contrast to the hookworm Ancylostoma caninum, and is not initiated by chemical exsheathment. No qualitative differences in protein secretion were induced by host serum as visualised by two-dimensional SDS–PAGE, although exposure of larvae to an aqueous extract of rat skin did stimulate secretion of a small pre-synthesised bolus of proteins. Infective larvae began feeding after a lag period of 3–4 h at 37 °C, reaching a maximum of 90% of the population feeding by 48 h. Neither a membrane permeant analogue of cyclic GMP nor muscarinic acetylcholine receptor agonists stimulated feeding at 20 °C, and high concentrations of both compounds inhibited temperature-induced activation. LY294002, an inhibitor of phosphatidylinositol 3-kinase, Akt inhibitor IV, an inhibitor of Akt protein kinase, and ketoconazole, an inhibitor of cytochrome P450, all blocked resumption of feeding and protein secretion at 37 °C. Serotonin increased the rate of feeding assessed by uptake of radiolabelled BSA, but could not initiate feeding independently of elevated temperature. Collectively, the data suggest that the early signalling events for larval activation in N. brasiliensis differ substantially from A. caninum, but that they may converge at pathways downstream of phosphatidylinositol 3-kinase involving steroid hormone synthesis.

The polymerization of diphenylacetylene derivatives possessing tert-amine moieties, such as triphenylamine, N-substituted carbazole and indole, was examined in the presence of TaCl5–n-Bu4Sn (1:2) catalyst. A polymer with high molecular weight (Mw = 570 × 103) was obtained in good yield by the polymerization of diphenylamine-containing monomer 1b, whereas the isopropylphenylamine derivative (1c) gave a polymer with relatively low molecular weight (Mw = 2.4 × 103). The polymerization of monomer 1d containing cyclohexylphenylamine group did not proceed; however, carbazolyl- and indolyl-containing monomers also produced polymers. Poly(1b), poly(2f) and poly(4b) could be fabricated into free-standing membranes by casting toluene solutions of these polymers. The gas permeability of poly(1b) was too low to be evaluated accurately whereas poly(4b) possessing two chlorine atoms in the repeating unit showed higher gas permeability than that of poly(1b); furthermore, poly(2f) having trimethylsilyl and 3-methylindolyl groups exhibited relatively high gas permeability ( P O 2 = 49 barrers ). In the cyclic voltammograms of diphenylamino group-containing polymers, poly(1b) and poly(2b), the intensities of oxidation and reduction peaks decreased more than those of carbazolyl-containing poly(2a). The molar absorptivity (ɛ) of poly(1b) at ∼700 nm increased with increasing applied voltage in the UV–vis spectrum.

A new fabrication process for designing nerve conduits with a porous ionic cross-linked alginate/chitosan composite for nervous regeneration could be prepared. New designed nerve conduits with a porous ionic cross-linked alginate/chitosan composite were developed for nervous regeneration. Nerve conduits (NCs) represent a promising alternative to conventional treatments for peripheral nerve repair. NCs composed of various polysaccharides such as sodium alginate were designed and prepared by lyophilization as potential matrices for tissue engineering. The use of a porous ionic cross-linked alginate/chitosan composite could provide penetration channels that would lead to the products' increasing penetration rate properties. Furthermore, the use of a porous ionic cross-linked alginate/chitosan composite also has a highly cross-linked structure, which would give the products relatively good mechanical properties. Furthermore, the drug could be incorporated into nerve conduits as a new drug-carrying system for nerve regeneration because of its porous and cross-linked structures.

The molecular architecture effect on active structure of miscellaneous polynorbornenes (Scheme 1) was investigated with pendant α,β-unsaturated amide or ester groups via ring-opening metathesis polymerization (ROMP). Remarkable differences in the reactivity and polymerization behavior of active norbornenes depend on various molecular architectures. Polynorbornenes derived from active norbornenes with ethylene between urethane group and ester group such as 3a,b (Scheme 1) showed excellent solubility. Organo-insoluble precipitate was obtained after ROMP of 5c with the amide group. Random copolymerization technique of bicyclo[2.2.1]hept-2-ene (NB) and 5c with amide group was considered to be a strategy to overcome the formation of precipitates, which expected to decrease the hydrogen bonding between two amide groups. High performance polynorbornenes with active groups could be designed with high potential of application for photoresist, UV curing and elastomers. Functional poly(5b) was incorporated into poly(methyl methacylate) [poly(MMA)] to produce AB cross-linked materials. The AB cross-linked material [15 wt% poly(5b), Td10=355 °C in nitrogen] had higher thermal stability than pure poly(MMA) (Td10=250 °C in nitrogen).

Novel organosoluble fluorescent polynorbornenes with multi-functional armed structure were designed and prepared by using highly stable block macroinitiators via a combination of living ring-opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP). A bromo-containing functional norbornene (NBMBr) was prepared from the Diels–Alder reaction of cyclopentadiene and allyl bromide. The diblock copolymer of 5-( N -carbazolyl methyl)bicycle[2.2.1]hept-2-ene (CbzNB) and NBMBr was successfully prepared using living ROMP and used as a novel macroinitiator [poly(CbzNB- b -NBMBr)] for ATRP. Carbazoyl-containing multi-functional armed copolymer with poly(methyl methacrylate) (PMMA) was prepared by using poly(CbzNB- b -NBMBr) as a macroinitiator for ATRP. Strong fluorescence emissions (370–450 nm) were observed in the low excimer-forming multi-functional armed fluorescent polynorbornenes. The fact is that low excimer-forming carbazole-containing polymeric compound would apparently be favorable in photoconductive materials. The multi-functional armed structure make this compound an attractive candidate for applications as multi-modified hole transport materials in molecular electronic devices. Multi-modification could be further considered to be carried out by using such a functional bromo group at the end of multi-arms.

A new diamine monomer containing noncoplanar methyl substitution, 2,2′-dimethyl-4,4′-bis(2-trifluoromethyl-4-aminophenoxy)biphenyl (DBTFAPB) was successfully synthesized and used in the preparation of a series of polyamides and polyimides by direct polycondensation with various aromatic dicarboxylic acids and tertacarboxylic dianhydrides. A new noncoplanar dicarboxylic acid monomer containing noncoplanar methyl substitution, 2,2′-dimethyl-4,4′-bis(2-trifluoromethyl-4-trimellitimidophenoxy)biphenyl (DBTFTPB) was also successfully synthesized by refluxing the diamine, DBTFAPB, with trimellitic anhydride in glacial acetic acid. A series of new poly(amide–imide)s were prepared directly from DBTFTPB with various diamines in N-methyl-2-pyrrolidinone (NMP). All the polymers exhibited excellent solubility in solvents, such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), pyridine, tetrahydrofuran (THF), cyclohexanone and γ-butyrolactone at room temperature or upon heating at 70 °C. Inherent viscosities of the polymers were found to range between 0.60 and 1.34 dL g−1. Gel permeation chromatography (GPC) of the polymers showed number-average and weight-average molecular weight up to 7.3×104 and 17.9×104, respectively. These polymers showed that the glass transition temperatures were between 230 and 265 °C, and the 10% mass loss temperatures were higher than 460 °C in nitrogen atmosphere. All the polymers could be cast into flexible and tough films from DMAc solutions. They had a tensile strength in the range of 82–124 MPa and a tensile modulus in the range of 1.9–2.9 GPa. These polymers exhibited low dielectric constants ranging from 2.87 to 4.03, low moisture absorption in the range of 0.29–3.20%, and high transparency with an ultraviolet–visible absorption cut-off wavelength in the 347–414 nm range.

Novel optically transparent and highly organo-soluble alicyclic polyimides derived from bulky alicyclic diamine containing trifluoromethyl group on either side, 1,1-bis[4(2-trifluoromethyl-4aminophenoxy)phenyl]-4-tert-butylcyclohexane (BTFAPBC), were prepared. All polymers showed excellent solubility in various organic solvents like N-methyl-2-pyrrolidinone (NMP), N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), pyridine, cyclohexanone, and γ-butyrolactone. The cut-off wavelength and 80% transmission wavelength for polyimides ranged from 362 to 407 nm and 436 to 492 nia, respectively. Polyimides with alicyclic tert-butylcyclohexyl cardo and trifluoromethyl substituents exhibited low dielectric constants ranging from 3.38 to 4.07 (at 1 KHz). Inherent viscosities of the polyimides were found to be in the range of 0.52-1.00 dL·g -1 . Polyimides showed glass transition temperatures in the range of 231-262 °C, and possessed a coefficient of thermal expansion (CTE) of 66-79 ppm.°C -1 . Thermogravimetric analyses of the polyimides revealed high thermal stability and decomposition temperature more than 450 °C in nitrogen atmosphere. The 10% weight loss temperature was found to be in the range of 453-544 and 413-502 °C in nitrogen and air atmospheres, respectively. The polyimide films had a tensile strength ranging from 84 to 100 MPa. The elongation at break varied from 6 to 12% and the tensile modulus varied from 1.1 to 2.1 GPa.

A novel organosoluble polynorbornene bearing a polar, pendant, ester-bridged epoxy group [poly(oxiran-2-ylmethyl 2-methylbicyclo[2.2.1]hept-5-ene-2-carboxylate) (polyOMMC)] was prepared via the living ring-opening metathesis polymerization (ROMP) of active norbornenes with a Ru catalyst. PolyOMMC exhibited excellent solubility in a variety of solvents. The number-average molecular weight of polyOMMC linearly increased with the [M]/[I] ratio (where [M] is the monomer concentration and [I] is the initiator concentration), and a narrow polydispersity of 1.09–1.19 was observed; this was considered a living polymerization. When ROMP of oxiran-2-ylmethyl 2-methylbicyclo[2.2.1]hept-5-ene-2-carboxylate with [M]/[I] = 350 was carried out at 30 °C in CH2Cl2, the number-average molecular weight (7.01 × 104; polydispersity index = 1.07) was close to the calculated molecular weight (7.28 × 104), and a diblock copolymer was observed after the addition of another monomer ([M]/[I] = 350) with an increase in the number-average molecular weight (1.60 × 105; polydispersity index = 1.11), which was close to the calculated molecular weight (1.61 × 105). The modified polynorbornenes retained good solubility in methylene chloride, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrdione. High-performance polynorbornenes with active epoxy groups could be designed with great potential for applications in photoresists, UV curing, and elastomers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4428–4434, 2006

Novel star-like polymeric materials with high cis content could be obtained by using α-norbornenyl macromonomers and highly stable macroinitiators derived from an active norbornene derivative [5-(2-bromo-2-methylpropionylaminomethyl)bicyclo[2.2.1]hept-2-ene (NBBrMPAM)], which was synthesized by the reaction of norbornene methylene amine and 2-bromo-2-methylpropionyl bromide. The α-norbornenyl macromonomer (NBPMMA), which is polymethyl methacrylate containing norbornenyl end group, was prepared by atom transfer radical polymerization (ATRP) using NBBrMPAM as an initiator. Star-like polynorbornene with high cis microstructure (cis/trans = 72/28) was obtained directly by ring-opening metathesis polymerization of NBPMMA macromonomer having number molecular weight (Mn) as low as 6.39 × 103. Random ring-opening metathesis copolymerization of NBPMMA and norbornene derivative containing carbazole group (NBCbz) was carried out at 25 °C by using Ru catalyst [(Cy3P)2Cl2Ru = CHPh, Cy = cyclohexyl, Ph = phenyl]. High cis (cis/trans = 63/37) organo-soluble star-like random poly(NBPMMA-co-NBCbz) was successfully obtained with high number-average molecular weight (Mn) of 4.76 × 104 and molecular weight distribution polydispersity index of 1.78. Organo-soluble comb-shaped copolymers with MMA could be successfully obtained using ATRP macroinitiator [poly(HNBBrMPAM)] in diluted macroinitiator solution with a concentration less than 3.64 × 10−2 mol.L−1. This is the first ever attempt to prepare novel star-like organo-soluble polymeric materials with high cis microstructure via the combination of ring-opening metathesis polymerization and ATRP. Multimodification could be considered to be carried out by using the functional bromo group at the end of side chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3382–3392, 2006

A novel doubly polymerizable functional norbornene, 5-(methacryloyloxyethylamino carboxylmethyl)bicyclo[2.2.1]hept-2-ene (NBMOACM), was prepared. The ring-opening metathesis polymerization (ROMP) of NBMOACM was carried out to prepare polymers with crosslinkable side chains with the Grubbs catalyst. No gel formation occurred during the ROMP of NBMOACM. The 1H NMR spectrum of poly(NBMOACM) showed broad signals between 5.10 and 5.40 ppm, corresponding to the vinyl protons of the cis and trans double bonds of the ring-opened polymer. Increasing the ratio of the monomer concentration to the catalyst concentration resulted in the formation of higher molecular weight polymers. Poly(NBMOACM) was incorporated into poly(methyl methacrylate) [poly(MMA)] to produce AB crosslinked materials. These crosslinked materials [1 wt % poly(NBMOACM), 10% weight loss temperature = 300 °C in air] had higher thermal stability than pure poly(MMA) (10% weight loss temperature = 276 °C in air). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6287–6298, 2006

The extent of intra- and interchain associations of (un)charged water-soluble monomers in the homogeneous and micellar solutions was studied with steady-state fluorescence spectroscopy. Fluorescence spectroscopic experiments were performed on uncharged (acryl amide) and charged hydrophilic monomers [zwitterionic 3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS), etc.] with pyrene as a probe. In both the homogeneous and micellar solutions, linear Stern–Volmer plots were obtained that implied that the quenching process can be considered as totally dynamic. The Stern–Volmer constant (KSV) for DMAPS decreased with an increasing dielectric constant of solvent and the concentration of simple electrolyte. An abrupt decrease in KSV was observed in the presence of a small amount of anionic emulsifier [below the critical micelle concentration (cmc)]. The dependence of KSV on pH for DMAPS was described by a curve with a maximum at about pH = 7. This was interpreted in terms of segregation of DMAPS and the variation of a optimal microenvironment for the probe and quencher with pH. The quenching rate in the micellar solutions strongly increased above the cmc but was lower than that in the homogeneous solutions. In the micellar solutions (above the cmc), the microenvironment for an interaction between the probe and quencher was suggested to be the whole microdroplet. The dependence of KSV on pH for DMAPS is described by a curve with a maximum at about pH = 9.3. The synergistic effect arises from the segregation of charged quencher molecules within the microdroplets. The complex (or strong interaction) between quencher and additive(s) is supposed to increase the dynamic nature of microdroplets that provides an optimal microenvironment for probe and quencher. A good coemulsifier, however, removes quencher from the interface and creates a barrier for entering monomer (quencher) into the core of micelles; therefore, quenching is depressed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 571–581, 2003

Photophysical and solution properties of pyrene-labeled poly(3-dimethyl(methylmethacryloyl ethyl) ammonium propane sulfonate), poly(DMAPS/Py), were studied in terms of fluorescence emission measurement. The I E /I M was shown as a function of polymer concentration in deionized water. I E /I M value decreases with an increase in the salt concentration. The addition of surfactants to the aqueous solution of poly(DMAPS/Py) can either induce the mixed micelle of intra- polymer and its surrounding surfactants and/or mixed micelle of inter-polymers and their surrounding surfactants. Models of interactions between poly(DMAPS/Py) and surfactant or divalent salt in aqueous solution are proposed.

This study describes the effect of salt on the aqueous solution property of the anionic terpolymer (SPM/NIPAM/PyMMA) of potassium-2-sulfopropylmethacrylate (SPM), N-isopropylacrylamide (NIPAM), and 1-pyrenemethylmethacrylate (PyMMA) in terms of fluorescence and dynamic light scattering. A plot of the thermally induced changes in I1/I3 and IE/IM ratios for pyrene-labeled SPM/NIPAM/PyMMA with various temperatures was showed. IE/IM value (the ratio of intensities of the excimer and the monomer fluorescence emission) of SPM/NIPAM/PyMMA, which reflects the interactions of pyrene groups and the probability of dimeric pyrene, was investigated. The ratio of intensity of the first to the third vibronic bands (I1/I3) in the fluorescence spectra of pyrene-labeled SPM/NIPAM/PyMMA depends on the polarity in the media, where pyrene exists. The IE/IM value of anionic terpolymer in aqueous solution varied with various surfactant (SDS) concentrations. Hydrodynamic diameters of anionic SPM/NIPAM/PyMMA in aqueous solution were also measured with various surfactant (SDS) concentrations. The same trends were obtained in fluorescence and dynamic light scattering measurements. At the lowered pH, the protonation of anionic terpolymer enhances hydrophobic association of polymer chains. The I1/I3 ratio decreases with increasing temperature, but the IE/IM ratio increases.

Ring-opening metathesis polymerization (ROMP) has been performed with {RuCl2(CHPh)[P(C6H11)3]2} catalyst to make low polydispersity block copolymers of 5-(N-carbazoyl methyl)bicyclo[2.2.1]hept-2-ene (CbzNB) and 5-(phthalimide methyl)bicyclo[2.2.1]hept-2-ene (NBMPI). Three diblock copolymers with the CbzNB and NBMPI were made, varying both molecular weight and percent of each block. The hydrogenated diblock copolymers were successfully obtained by using p-toluenesulfonylhydrazide as a reducing agent. The novel diblock copolymers were characterized by means of gel permeation chromatography (GPC) 1H NMR, fluorescence, differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The molecular weight distributions of the diblock copolymers are narrow ( M w / M n ∼1.5). Unhydrogenated diblock copolymers exhibited a strong carbazole fluorescence, with monomer emission occurring in the near-UV at approximately 380 nm and extending into the blue–violet region. Similar results were also observed on hydrogenated diblock copolymers. All diblock copolymers exhibited good solubility in a variety of solvents such as methylene chloride, chloroform, tetrahydrofuran and 1,2-dichlorobenzene; however, there was no remarkable difference between unhydrogenated and hydrogenated diblock copolymers. Two Tg values were observed for the CbzNB segment and the NBMPI segment before and after hydrogenation. Unhydrogenated diblock copolymers exhibited good thermo-oxidative stability, losing 10% mass in the range 369–389°C in air and 400–416°C in nitrogen. However, hydrogenated diblock copolymers showed better thermal stability than unhydrogenated diblock copolymers, and 10% mass loss temperatures were recorded in the range 375–396°C in air and 415–428°C in nitrogen.

Water-soluble polymers, cationic poly(trimethyl methacrylamidophenyl ammonium methylsulfate) [poly(TMMAPhAMS)] and zwitterionic poly(N,N-dimethylmethacrylamidophenyl ammonium propane sultone) [poly(DMMAPhAPS)], derived from N,N-dimethylaminophenyl methacrylamide (DMAPMA) were studied in terms of their solubility, viscosity, ultraviolet absorption, fluorescence properties, quasielastic light scattering and surface activity. The critical solution temperature of poly(DMMAPhAPS) and poly(TMMAPhAMS) observed was below 0°C showing that both have good solubility. These water-soluble polymers exhibited both ultraviolet absorption and fluorescence emission properties. The ultraviolet absorption of poly(DMMAPhAPS) (245 nm) showed a 2 nm red shift as compared to that of poly(TMMAPhAMS) (243 nm), suggesting that the microenvironment around the phenyl moiety of poly(DMMAPhAPS) is more hydrophobic in poly(TMMAPhAMS). With increasing salt concentration, the average hydrodynamic diameter of cationic poly(TMMAPhAMS) decreases from 640 to 200 nm, while that of poly(DMMAPhAPS) increases from about 300 to 750 nm. The surface tension of zwitterionic poly(DMMAPhAPS) decreases continuously in an almost linear dependence on logarithm concentration at higher polymer concentrations (>2.5×10 −3 M ), with no break indicative of micelle formation.

Copolymers of cationic trimethyl(4-methacrylamidophenyl)ammonium methyl sulfate (TMMAPhAMS) or zwitterionic 3-dimethyl(4-methacrylamidophenyl)ammonato propane sulfonate (DMMAPhAPS) monomer with methacrylamide (MAA) have been prepared by free radical polymerization using 4,4′-azobis-cyanovaleric acid as an initiator in aqueous solution. Copolymer compositions were obtained by elemental analysis. The monomer reactivity ratios were calculated by the Fineman–Ross and Kelen–Tudos methods. The r1r2=0.17 for TMMAPhAMS/MAA copolymer and r1r2=0.34 for DMMAPhAPS/MAA copolymer, using the Fineman–Ross treatment, exhibit a slight tendency toward alternation. The microstructure of the cationic copolymer series (TMMAPhAMS/MAA) is more alternating than that of the zwitterionic series (DMMAPhAPS/MAA). A similar phenomenon was observed using the Kelen–Tudos treatment. The statistical distribution of monomer sequences was calculated by the Pyun method. From the microstructure data, the alternation and the blockiness amounts were determined. The dilute-solution properties of the two copolymer series have been studied in related to their composition and added electrolytes.

Different types of sulfobetaines and their corresponding cationic monomers and polymers derived from N,N-dialkylamino phenyl methacrylamide have been synthesized for this study. Comparing the chemical shifts in 1 H and 13 C NMR of the methylene groups in the cationic monomers and betaines reveal that the respective methylene groups are clearly distinguishable from each other. Results obtained from the intrinsic viscosity for zwitterionic poly(DEMAPhAPS) are opposite to that for the corresponding cationic poly(DEMMAPhAMS).

Interaction between naphthalene-labeled poly(hydrochloride quaternized 2-norbornene-5-methyleneamine), poly(HCQNBMA)/NA (luminophore), and quencher, emulsifier or coemulsifier in the aqueous or microemulsion media was studied by using steady-state fluorescence measurements. Fluorescence experiments were carried out with poly(HCQNBMA)/NA dissolved in the aqueous solutions of ionic and nonionic emulsifiers, emulsifier/n-hexane/water microemulsion (A) and emulsifier/n-hexane/1-pentanol/water microemulsion (B), respectively. The intensity of fluorescence emission of poly(HCQNBMA)/NA was much higher in the aqueous phase than in microemulsion. Furthermore, the aqueous solution of ionic emulsifier increased the monomer emission. The increase in the monomer emission can be ascribed to the shielding of the naphthalene (NA) groups by SDS micelles. This separates NA groups from each other, which depresses the deactivation of excited states. The strong decrease in monomer emission within the microemulsion media probably results from the elongated conformation structure of the polymer molecule, and higher conformation freedom of NA groups, which increases interaction between the probe and the quencher. The formation of nonfluorescence clusters is not ruled out. The quenching of NA emission by nitromethan (NM) is much stronger in microemulsion than in the aqueous phase, and the quenching is more pronounced for the low molecular weight 2-norbornene-5-methoxylnaphthalene (NBMNA) than for its polymer. The extent of penetration of reactants into the interfacial layer governs quenching of hydrophobic NA probe by hydrophilic quencher. Furthermore, the quenching events are connected with the thickness and density of the interfacial layer, as well as its charge. The addition of coemulsifier (1-pentanol) increases the total surface area of the microdroplets, the entry rate of reactants into the microdroplets, and the interaction of hydrophobic and hydrophilic reactants. The quenching events are more pronounced in the close packed o/w interfacial layer than in the loosely packed one. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 101–114, 2001

The copolymers derived from zwitterionic DMAPAMAIPS and hydrophobic monomer (AdMAI or NaMAI) were studied in terms of the surface tension, viscometrics, and photophysical measurements. The surface tension of poly(DMAPAMAIPS) was shown to be larger than that of both the copolymer [poly(DMAPAMAIPS/NaMAI)] with an aromatic hydrophobic residue (naphthalene group) and [poly(DMAPAMAIPS/AdMAI)] with an aliphatic hydrophobic residue (adamantane group). The copolymer [poly(DMAPAMAIPS/NaMAI)] has a larger surface activity than that of [poly(DMAPAMAIPS/AdMAI)]. The reduced viscosity of the copolymers revealed that both zwitterionic and hydrophobic associations were important in polymer aggregation. The aromatic hydrophobic units of the copolymer [poly(DMAPAMAIPS/NaMAI)] were more strongly associated than the units of aliphatic hydrophobic copolymer [poly(DMAPAMAIPS/AdMAI)] due to the stronger hydrophobic aggregation of naphthyl groups. The fluorescence experiment showed that when the hydrophobic adamantyl group was ...

The relationship between the structure and property of polyurethane elastomer derived from bisphenol-S derivatives/diisocyanate system was studied. The effects of the amount of soft segment of diol, including ester and ether, as well as the effects of structure of diisocyanate on the mechanical properties of elastomer were discussed on the basis of the results obtained from the hardness, tensile strength, elongation, swelling, dynamic mechanical analysis, and X-ray diffraction. Also, the thermal properties of polyurethane elastomer were also investigated by d.s.c. and t.g.a. analyses. The d.s.c. and dynamic properties results demonstrated that the new polyurethanes exhibit a range of glass transition temperatures from − 25 to 48°C, and temperature at loss tan δ peak from 81.0 to 13.7°C. Moreover, t.g.a. results showed that the addition of an ester group increased the thermal stability of polyurethanes.

The aqueous solution properties of an ampholytic naphthalene-labelled acrylamide/N,N-dimethyl maleimido propyl ammonium propane sulphonate copolymer, poly(ADMMAPS)/NA, are examined in this study by measuring reduced and intrinsic viscosities. The intrinsic viscosity of the poly(ADMMAPS)/NA is related to the type and concentration of the salt added. This behaviour, resulting from the associations of the polymer chains, is in contrast with cationic and anionic polyelectrolytes. Smaller anions, such as F-, with a common cation (K+) are found to be the most difficult to be bound to the sulphonate group, indicating that a lower intrinsic viscosity of the poly(ADMMAPS)/NA would be found in aqueous KF solution. Smaller cations, such as Li+, with a common anion (Cl-) are found to be the most difficult to be bound to the quaternary ammonium group, indicating that a lower intrinsic viscosity of the poly(ADMMAPS)/NA would be found in LiCl salt aqueous solution. Because a naphthalene label was introduced into the polymer, the behaviour of the solution properties of the poly(ADMMAPS)/NA could be clearly defined in term of macroscopic and microscopic analysis. The models proposed in this study can account for the poly(ADMMAPS)/NA solution viscosities. © 1998 SCI.

The photophysical and solution properties of naphthalene-labeled styrene/N,N-dimethyl maleimido propylammonium propane sulfonate copolymer, poly(SDMPAPS)/NA, were studied in terms offluorescence, cloud point, and viscosity measurements. The ratio of intensities of the excimer and monomer fluorescence (I E /I M ) was shown as a function of polymer concentration in deionized water. The value of I E /I M decreases with an increase in the salt concentration. The addition of anionic surfactants to the aqueous solution of poly(SDMPAPS)/NA can either induce or break the interpolymer aggregation. When the electrolyte concentration increases, the Stern-Volmer quenching constant (K sv ) also increases. The phase behavior of poly(SDMPAPS)/NA shows an upper critical solution temperature around 17 °C. The intrinsic viscosity of the poly(SDMPAPS)/NA in the presence of different salts reflects the influence of these salts on the hydrodynamic volume of the polymer chain for poly(SDMPAPS)/NA. A model of the interaction between poly(SDMPAPS)/NA and surfactant in aqueous solution is proposed.

Two types of carboxybetaines and their corresponding cationic monomers and polymers are synthesized in this study. Comparing the chemical shifts of the methylene groups in the cationic monomers and carboxybetaines in both 1H- and 13C-NMR spectra reveal that the respective methylene groups are clearly distinguished from their chemical shifts in 1H- and 13C-NMR spectra. The solubilities, moisture regain properties, and solution properties of the poly(carboxybetaine)s and cationic polymers are investigated in relation to their molecular structures. Because the cationic polymers were ionized in an aqueous solution, the cationic polymers were more soluble than the poly(carboxybetaine). For the various functional groups of poly(carboxybetaine)s and cationic polymers, the order of tendency for moisture regain is COO > CONH. Results obtained from the reduced viscosity for cationic poly(TMMPAMS) are reversed from that for zwitterionic poly(DMAEAPL). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3527–3536, 1997

Numerous materials have been proposed for bone tissue engineering. In this study, a newly designed hybrid composite scaffold composed of poly (D,L-lactide-co-glycolide) and a naturally bioceramic hybrid material, nanonized pearl powder, were prepared and the biological activities and physical properties of the scaffold for bone tissue engineering were evaluated. It is a composite consisting calcium carbonate crystal in an aragonite structure, embedded in an organic matrix. Peral contains one or more signal molecules capable of stimulating bone formation. The nanonized pearl powder is considered as a promising osteoinductive biomaterial. This biomaterial is biocompatible and shows osteogenic activity. In this study, the designed biohybrid of nanonized pearl powder/poly (lactide-co-glycolide) (NPP/PLGA) biocomposite scaffolds would employ biodegradable material as MC3T3-E1 cells seeded scaffolds. Therefore, the biocomposite scaffolds would be used to culture with MC3T3-E1 cells under spinner bioreactor in vitro. Furthermore, it also detailed how these tissues were characterized, qualitatively and quantitatively, with scanning electron microscopy and biochemical testing. The identity and the mode of action of these molecules on the osteoblast differentiation were analyzed. This study indicates that the efficiency of nanonized pearl powders in bone cell differentiation are certainly different from that of proteins. Further sudy will look forward to manufacturing the promising new generation bone substitute, three dimensional biocomposite scaffolds to replace the implant and autogeneous bone graft, which combines basic research and clinical application.

New designed combined products and its determination for pain management and cancer treatment were studied. A rapid and sensitive stability indicating HPLC method had been developed and validated for the determination of Indometha- cin(IDM) in a transdermal patch. This analytical method was successfully applied to the determination of Indomethacin in a transdermal patch and can be used for routine quality control analysis. Chromatographic separation was achieved isocratical- ly on an Inertsil ® C8-3 column utilizing a mobile phase of acetonitrile / 0.01 M monobasic sodium phosphate and 0.01M dibasic sodium phosphate buffer (pH 3) (65:35, v/v) at the flow rate of 1 mL/min with UV detection at the wavelength of 210 nm. The system suitability was performed, and the result showed that Indomethacin(IDM) and its impurity were separated. The calibration curve of Indomethacin(IDM) was linear in the range of 0.1~15 ppm (r = 0.9989, n = 3).

The dilute solution properties of an anionic polyelectrolyte, poly(potassium-2-sulphopropylacrylate) (poly(SPA)) are studied by measurements of intrinsic viscosity, degree of binding, ionic strength and critical micelle concentration. The intrinsic viscosity of this polyelectrolyte is related to the type and concentration of the salt added. The intrinsic viscosity behaviour of an anionic polyelectrolyte resulting from the electrostatic repulsive force of the polymer chain is in contrast to that of a polyampholyte. The polyelectrolyte in high concentration of NaCl has a low degree of binding, indicating that the proton ion (H + ) is relatively difficult to bind to the sulphonate group (SO 3 - ) at the polymer end. An increase in ionic strength causes the pK a to decrease at the half-neutralization point. The monomer solutions exhibit a plot typical of those observed for detergents, with a break in the curve occurring at the critical micelle concentration. For the polymer solutions, no break in the equivalent conductance curve was found for the concentrations studied.