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PubMed2004

The small GTPase Cdc42 regulates actin polymerization and tension development during contractile stimulation of smooth muscle.

Contractile stimulation induces actin polymerization in smooth muscle tissues and cells, and the inhibition of actin polymerization depresses smooth muscle force development. In the present study, the role of Cdc42 in the regulation of actin polymerization and tension development in smooth muscle was evaluated. Acetylcholine stimulation of tracheal smooth muscle tissues increased the activation of Cdc42. Plasmids encoding wild type Cdc42 or a dominant negative Cdc42 mutant, Asn-17 Cdc42, were introduced into tracheal smooth muscle strips by reversible permeabilization, and tissues were incubated for 2 days to allow for protein expression. Expression of recombinant proteins was confirmed by immunoblot analysis. The expression of the dominant negative Cdc42 mutant inhibited contractile force and the increase in actin polymerization in response to acetylcholine stimulation but did not inhibit the increase in myosin light chain phosphorylation. The expression of wild type Cdc42 had no significant effect on force, actin polymerization, or myosin light chain phosphorylation. Contractile stimulation increased the association of neuronal Wiskott-Aldrich syndrome protein with Cdc42 and the Arp2/3 (actin-related protein) complex in smooth muscle tissues expressing wild type Cdc42. The agonist-induced increase in these protein interactions was inhibited in tissues expressing the inactive Cdc42 mutant. We conclude that Cdc42 activation regulates active tension development and actin polymerization during contractile stimulation. Cdc42 may regulate the activation of neuronal Wiskott-Aldrich syndrome protein and the actin related protein complex, which in turn regulate actin filament polymerization initiated by the contractile stimulation of smooth muscle.

Acetylcholine↗
PubMed2002

Influence of composition on rate of polymerization contraction of light-curing resin composites.

A slow contraction may result in reduced gap formation when a restorative resin polymerizes in a dental cavity. It was the aim in the present work to investigate the rate of contraction in relation to composition of experimental light-curing resin composites. The monomer of the resin composites consisted of mixtures of BisGMA, TEGDMA, and in one series HEMA. The resins contained varying amounts of initiators, co-initiators, and inhibitor, and were made composite by adding a silanized glass filler to a content of 74% by weight of the composite paste. The polymerization contraction up to 120 sec was determined by means of the bonded-disk method. Within the ranges studied, the concentration of initiator and co-initiator in the monomer mixture had only an insignificant influence on rate of polymerization. In comparison to camphorquinone, the initiators 1-phenyl-1,2-propanedione and benzil reduced the rate of polymerization without affecting the final contraction. In comparison to N,N-dimethyl-p-aminobenzoic acid ethyl ester, N,N-cyanoethyl methylaniline was as effective, while N,N-diethanol-p-toluidine was less effective as co-initiator. A relatively high content of the inhibitor methoxyhydroquinone reduced the initial rate but not the final polymerization contraction. The rate of polymerization increased with the level of HEMA and TEGDMA in the monomer mixture. It was concluded that intrinsic slow cure may be obtained with certain compositions of resin composites without impairing the final extent of polymerization.

4-Aminobenzoic Acid↗
PubMed2000

Effect of novel water-soluble polymeric forms of sorbic acid against Fusarium oxysporum f.sp. radicis-cucumerinum.

New controlled release water-soluble formulations of sorbic (2,4-hexadienoic) acid were prepared and their inhibitory activity on mycelium growth of Fusarium oxysporum f.sp. radicis-cucumerinum was evaluated. The new products are epoxidized polymers of polyvinylpyrrolidone (PVP) containing covalently bonded sorbic acid (polymeric esters of sorbic acid) and complexes of PVP with hydrogen bonded sorbic acid, characterized by controlled release of sorbic acid. It was shown that the polymeric complexes of sorbic acid with PVP were more effective fungicidal agents than sorbic acid polymeric esters. In all cases the activity of polymeric derivatives (esters and complexes) was increased by lowering the molecular weight of the polymeric carriers. Controlled release formulations of these polymeric derivatives are new promising products due to their low toxicity, wide range of efficient concentrations for application and ability to regulate lyophilicity. Our data contribute to the understanding of the action mechanism of various polymeric sorbic acid formulations and can result in products which are particularly suitable for food and feed protection applications.

Delayed-Action Preparations↗
PubMed2003

Growth enhancement in broiler chickens receiving CHEMEQRTM polymeric antimicrobial.

This study investigated the use of CHEMEQRTM polymeric antimicrobial as a means of enhancing health and growth rates in broiler chickens. One-day-old Cobb-500 broilers were reared to 42 days. In trial 1, 100 birds received CHEMEQRTM polymeric antimicrobial via water, and 100 birds were untreated. Treated birds had significantly greater (P<0.0001) average daily gain (ADG), significantly lower (P<0.0016) feed conversion ratios, significantly lower (P<0.05) mortality, and a significantly lower (P<0.0042) viscosity of their ileal contents. In trial 2, three groups of 40 birds received reducing dosages of CHEMEQRTM polymeric antimicrobial, and a fourth group remained untreated. Groups receiving CHEMEQRTM polymeric antimicrobial had significantly greater (P<0.05) ADG, and two groups had significantly lower (P<0.05) feed conversion ratios than the controls. In trial 3, groups of 40 birds received either CHEMEQRTM polymeric antimicrobial, Salinomycin or Lasalocid in-feed, or were untreated. Birds receiving CHEMEQRTM polymeric antimicrobial had significantly greater (P<0.05) ADG than those receiving Salinomycin. CHEMEQRTM polymeric antimicrobial helped to maintain the health and to improve the growth performance of broiler chickens.

Animals↗
PubMed1989

Identification of actin nucleation activity and polymerization inhibitor in ameboid cells: their regulation by chemotactic stimulation.

Actin polymerization occurs in amebae of Dictyostelium discoideum after chemotactic stimulation (Hall, A. L., A. Schlein, and J. Condeelis. 1988. J. Cell. Biochem. 37:285-299). When cells are lysed with Triton X-100 during stimulation, an actin nucleation activity is detected in lysates by measuring the rate of pyrene-labeled actin polymerization. This stimulated nucleation activity is closely correlated with actin polymerization observed in vivo in its kinetics, developmental regulation, and cytochalasin D sensitivity. Actin polymerization is coordinate with pseudopod extension in synchronized populations of cells and is correlated with the accumulation of F actin in pseudopods. The stimulated actin nucleation activity is present in low-speed pellets from Triton lysates (cytoskeletons) within 3 s of stimulation and is stable compared with the nucleation activity of whole cell lysates. Low-speed supernatants contain a reversible inhibitor of the actin nucleation activity that is itself regulated by chemotactic stimulation. Neither activity requires Ca2+ and both are fully expressed in 10 mM EGTA. Fractions containing the inhibitor do not sever actin filaments but do inhibit actin polymerization that is seeded by fragments of purified F actin. These results indicate that chemotactic stimulation of Dictyostelium discoideum generates both an actin-nucleating activity and an actin-polymerization inhibitor, and suggest that the parallel regulation of these two activities leads to the transient phases of actin polymerization observed in vivo. The different compartmentation of these two activities may account for polarized pseudopod extension in gradients of chemoattractant.

Actins↗
PubMed1993

Activation of actin polymerization by phosphatidic acid derived from phosphatidylcholine in IIC9 fibroblasts.

alpha-Thrombin induced a change in the cell morphology of IIC9 fibroblasts from a semiround to an elongated form, accompanied by an increase in stress fibers. Incubation of the cells with phospholipase D (PLD) from Streptomyces chromofuscus and exogenous phosphatidic acid (PA) caused similar morphological changes, whereas platelet-derived growth factor (PDGF) and phorbol 12-myristate 13-acetate (PMA) induced different changes, e.g., disruption of stress fibers and cell rounding. alpha-Thrombin, PDGF, and exogenous PLD increased PA by 20-40%, and PMA produced a smaller increase. alpha-Thrombin and exogenous PLD produced rapid increases in the amount of filamentous actin (F-actin) that were sustained for at least 60 min. However, PDGF produced a transient increase of F-actin at 1 min and PMA caused no significant change. Dioctanoylglycerol was ineffective except at 50 micrograms/ml. Phospholipase C from Bacillus cereus, which increased diacylglycerol (DAG) but not PA, did not change F-actin content. Down-regulation of protein kinase C (PKC) did not block actin polymerization induced by alpha-thrombin. H-7 was also ineffective. Exogenous PA activated actin polymerization with a significant effect at 0.01 microgram/ml and a maximal increase at 1 microgram/ml. No other phospholipids tested, including polyphosphoinositides, significantly activated actin polymerization. PDGF partially inhibited PA-induced actin polymerization after an initial increase at 1 min. PMA completely or largely blocked actin polymerization induced by PA or PLD. These results show that PC-derived PA, but not DAG or PKC, activates actin polymerization in IIC9 fibroblasts, and indicate that PDGF and PMA have inhibitory effects on PA-induced actin polymerization.

Actins↗
PubMed1998

Mechanism of Cdc42-induced actin polymerization in neutrophil extracts.

Cdc42, activated with GTPgammaS, induces actin polymerization in supernatants of lysed neutrophils. This polymerization, like that induced by agonists, requires elongation at filament barbed ends. To determine if creation of free barbed ends was sufficient to induce actin polymerization, free barbed ends in the form of spectrin-actin seeds or sheared F-actin filaments were added to cell supernatants. Neither induced polymerization. Furthermore, the presence of spectrin-actin seeds did not increase the rate of Cdc42-induced polymerization, suggesting that the presence of Cdc42 did not facilitate polymerization from spectrin-actin seeds such as might have been the case if Cdc42 inhibited capping or released G-actin from a sequestered pool. Electron microscopy revealed that Cdc42-induced filaments elongated rapidly, achieving a mean length greater than 1 micron in 15 s. The mean length of filaments formed from spectrin-actin seeds was <0.4 micron. Had spectrin-actin seeds elongated at comparable rates before they were capped, they would have induced longer filaments. There was little change in mean length of Cdc42-induced filaments between 15 s and 5 min, suggesting that the increase in F-actin over this time was due to an increase in filament number. These data suggest that Cdc42 induction of actin polymerization requires both creation of free barbed ends and facilitated elongation at these ends.

Actin Cytoskeleton↗
PubMed2004

Processive capping by formin suggests a force-driven mechanism of actin polymerization.

Regulation of actin polymerization is essential for cell functioning. Here, we predict a novel phenomenon-the force-driven polymerization of actin filaments mediated by proteins of the formin family. Formins localize to the barbed ends of actin filaments, but, in contrast to the standard capping proteins, allow for actin polymerization in the barbed direction. First, we show that the mechanism of such "leaky capping" can be understood in terms of the elasticity of the formin molecules. Second, we demonstrate that if a pulling force acts on the filament end via the leaky cap, the elastic stresses can drive actin polymerization. We estimate that a moderate pulling force of approximately 3.4 pN is sufficient to reduce the critical actin concentration required for barbed end polymerization by an order of magnitude. Furthermore, the pulling force increases the polymerization rate. The suggested mechanism of force-driven polymerization could be a key element in a variety of cellular mechanosensing devices.

Actins↗
PubMed1999

Dynamics of polymerization in polyacrylamide gel (PAG) dosimeters: (I) ageing and long-term stability.

Few quantitative data are available on the kinetics of polymerization reactions in polymer gel (PAG) dosimeters and their long-term stability. Post-irradiation polymerization reactions have been found to continue for several weeks, posing questions regarding dosimeter stability and its achievement. In this paper we report an investigation of polymerization kinetics in PAG dosimeters and the effect of diffusing oxygen into the dosimeter, post irradiation, as a potential method of inhibiting further polymerization and stabilizing the dose distribution. Results show continuous post-irradiation changes in transverse relaxation rate R2 with time over the five week study period and that a steady-state may not be reached for a period of months. An assessment is made of the appropriate time to image the dosimeter which shows that after three to four days the polymerization change is slow compared with imaging time. The implications of the time delay between irradiation and imaging are discussed in terms of the resultant sensitivity of the dosimeter and accuracy of the dose measured. In pairs of dosimeters, one sealed the other open to air, oxygen diffusing into the dosimeter arrests polymerization. However, the diffusion rate is too slow to make this method practicable. The slow diffusion means that while in regions near the air/gel interface polymerization is quickly arrested, in deeper regions it may continue for many hours, causing artefacts in the dose distribution. In the companion paper to this from a collaborating team, a study focusing on modelling oxygen diffusion in dosimeter gel will be presented.

Acrylic Resins↗
PubMed2004

Nonionic polymeric micelles for oral gene delivery in vivo.

The main aim of this study was to investigate the feasibility of using nonionic polymeric micelles of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) as a carrier for oral DNA delivery in vivo. The size and appearance of DNA/PEO-PPO-PEO polymeric micelles were examined, respectively, by dynamic light scattering and atomic force microscopy, and their zeta potential was measured. Expression of the delivered lacZ gene in various tissues of nude mice was assessed qualitatively by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining of sections and quantitatively by measuring enzyme activity in tissue extracts, using the substrate of beta-galactosidase, chlorophenol red-beta-D-galactopyranoside. In addition, the types of cells expressing the lacZ gene in the duodenum were identified by histological analysis. DNA/PEO-PPO-PEO polymeric micelles are a single population of rounded micelles with a mean diameter of 170 nm and a zeta potential of -4.3 mV. Duodenal penetration of DNA/PEO-PPO-PEO polymeric micelles was evaluated in vitro by calculating the apparent permeability coefficient. The results showed a dose-independent penetration rate of (5.75 +/- 0.37) x 10(-5) cm/sec at low DNA concentrations (0.026-0.26 microg/microl), but a decrease to (2.89 +/- 0.37) x 10(-5) cm/sec at a concentration of 1.3 microg/microl. Furthermore, when 10 mM RGD peptide or 10 mM EDTA was administered before and concurrent with the administration of DNA/PEO-PPO-PEO polymeric micelles, transport was inhibited ([0.95 +/- 0.57] x 10(-5) cm/sec) by blocking endocytosis or enhanced ([29.8 +/- 5.7] x 10(-5) cm/sec) by opening tight junctions, respectively. After oral administration of six doses at 8-hr intervals, the highest expression of transferred gene lacZ was seen 48 hr after administration of the first dose, with gene expression detected in the villi, crypts, and goblet cells of the duodenum and in the crypt cells of the stomach. Reporter gene activity was seen in the duodenum, stomach, and liver. Activity was also seen in the brain and testis when mice were administered 10 mM EDTA before and concurrent with DNA/PEO-PPO-PEO polymeric micelle administration. lacZ mRNA was detected in these five organs and in the blood by reverse transcription-polymerase chain reaction. Taken together, these results show efficient, stable gene transfer can be achieved in mice by oral delivery of PEO-PPO-PEO polymeric micelles.

Administration, Oral↗
PubMed2003

A redox-sensitive loop regulates plasminogen activator inhibitor type 2 (PAI-2) polymerization.

Plasminogen activator inhibitor type 2 (PAI-2) is the only wild-type serpin that polymerizes spontaneously under physiological conditions. We show that PAI-2 loses its ability to polymerize following reduction of thiol groups, suggesting that an intramolecular disulfide bond is essential for the polymerization. A novel disulfide bond was identified between C79 (in the CD-loop) and C161 (at the bottom of helix F). Substitution mutants in which this disulfide bond was broken did not polymerize. Reactive center loop peptide insertion experiments and binding of bis-ANS to hydrophobic cavities indicate that the C79-C161 disulfide bond stabilizes PAI-2 in a polymerogenic conformation with an open A-beta-sheet. Elimination of this disulfide bond causes A-beta-sheet closure and abrogates the polymerization. The finding that cytosolic PAI-2 is mostly monomeric, whereas PAI-2 in the secretory pathway is prone to polymerize, suggests that the redox status of the cell could regulate PAI-2 polymerization. Taken together, our data suggest that the CD-loop functions as a redox-sensitive switch that converts PAI-2 between an active stable monomeric and a polymerogenic conformation, which is prone to form inactive polymers.

Cysteine↗
PubMed1976

Abnormal fibrin polymerization in liver disease.

Although there have been isolated reports of an acquired abnormal fibrinogen in patients with liver disease, its frequency and clinical significance is not known. In this study 121 consecutive patients with a wide spectrum of hepatic disorders were screened for abnormal fibrin polymerization. A simple colorimetric method using Reptilase was employed. Of 32 patients with proven cirrhosis, 16 (50%) showed abnormal fibrin polymerization. The incidence in decompensated alcoholic cirrhosis was particularly high. The abnormality was also detected in all patients with acute liver failure and seven of 15 with chronic active liver disease. Clinical improvement often correlated with its disappearance. Two patients with primary liver cell tumours demonstrated the abnormal polymerization. In patients with bleeding oesophageal varices the detection of abnormal fibrin polymerization was associated with a poor prognosis. None of the patients with surgical obstructive jaundice (26) or miscellaneous liver disorders (37) had abnormal fibrin polymerization. The occurrence of abnormal fibrin polymerization in liver disease is more frequent than previously suspected and usually signifies severe primary hepatocellular dysfunction. Evidence is presented to support the presence of a primary abnormality of fibrinogen as the cause of impaired fibrin monomer polymerization.

Batroxobin↗
PubMed1986

Temperature control in Lowicryl K4M and glycol methacrylate during polymerization: is there a low-temperature embedding method?

An apparatus for embedding tissues at resin temperatures down to 228 K is described. By placing thermocouples in the resin the temperature has been monitored during embedding at low temperature with glycol methacrylate (GMA) and Lowicryl K4M. Even in this apparatus with a liquid cooling bath the heat of polymerization is not dissipated and the resin temperature rises. This rise is directly proportional to the resin temperature at the onset of polymerization and is higher in Lowicryl K4M than GMA. The initial resin temperature also affects the time taken for polymerization. The time to the onset of the peak and its duration are both increased as the temperature is lowered. This effect is more pronounced with GMA than Lowicryl K4M and polymerization of GMA is inhibited at the lowest temperature used. When Lowicryl K4M, polymerized at low temperature, is warmed up to ambient a further exothermic reaction occurs, which causes the resin temperature to rise well above ambient. Both this temperature peak and that during polymerization are reduced, but not totally eliminated, by reducing the resin volume. Air-cooled systems are inefficient compared with the low-temperature apparatus used here and the resin temperature rise is consequently greater and, even with small resin volumes, it can be very high. It is therefore unlikely for published methods that the temperature specified has been maintained in the resin during polymerization. The implications of these findings are discussed in relation to enzyme and antigen survival. Recommendations include use of very small volumes of resin, refrigerated liquid-bath rather than air-cooled systems and contact with a heat sink when specimens are warmed up to ambient temperature. Examples of enzyme reaction, antigen survival and structural preservation obtained with the method are presented.

Acrylates↗
PubMed2005

A new method to measure the polymerization shrinkage kinetics of light cured composites.

This study was undertaken to develop a new measurement method to determine the initial dynamic volumetric shrinkage of composite resins during polymerization, and to investigate the effect of curing light intensity on the polymerization shrinkage kinetics. The instrument was basically an electromagnetic balance that was constructed with a force transducer using a position sensitive photo detector (PSPD) and a negative feedback servo amplifier. The volumetric change of composites during polymerization was detected continuously as a buoyancy change in distilled water by means of the Archimedes' principle. Using this new instrument, the dynamic patterns of the polymerization shrinkage of seven commercial composite resins were measured. The polymerization shrinkage of the composites was 1.92 approximately 4.05 volume %. The shrinkage of a packable composite was the lowest, and that of a flowable composite was the highest. The maximum rate of polymerization shrinkage increased with increasing light intensity but the peak shrinkage rate time decreased with increasing light intensity. A strong positive relationship was observed between the square root of the light intensity and the maximum shrinkage rate. The shrinkage rate per unit time, dVol%/dt, showed that the instrument can be a valuable research method for investigating the polymerization reaction kinetics. This new shrinkage-measuring instrument has some advantages that it was insensitive to temperature changes and could measure the dynamic volumetric shrinkage in real time without complicated processes. Therefore, it can be used to characterize the shrinkage kinetics in a wide range of commercial and experimental visible-light-cure materials in relation to their composition and chemistry.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1981

Effects of formamide on the polymerization and depolymerization of muscle actin.

Formamide was found to interfere with the polymerization of electrophoretically pure rabbit skeletal muscle G-actin to F-actin in vitro. It decreased the rate as well as the extent of polymerization. However, this influence was dependent on the way the polymerization reaction was initiated. If polymerization of G-actin was induced by 2 mM MgCl2, formamide inhibited the rate and extent of the polymerization much less than if the polymerization was induced by either 2 mM CaCl2 or 0.1 M KCl. The critical protein concentration was increased when formamide was present. This effect was small in the presence of MgCl2 but an approximately tenfold increase in the critical value was observed for the CaCl2-induced or KCl-induced polymerization. Depolymerization of F-actin by molar amounts of formamide was faster and proceeded further when the polymer had been formed in the presence of KCl or CaCl2 than when it been formed in the presence of MgCl2. It is concluded that Mg2+ stabilizes the F-actin structure rendering it more resistant than either Ca2+ or K+ against the destabilizing action of formamide.

Actins↗
PubMed1981

Inhibition of lactate dehydrogenase activity by polymeric NAD derivatives with different NAD densities.

Polymeric NAD derivatives with different NAD densities were prepared by the copolymerization of NAD N6-[N-(N-acryloyl-1-methoxycarbonyl-5-aminopentyl)-propionamide] with acrylamide in different molar ratios, from 4 x 10(-4) to 1 x 10(-2). The cofactor activities of the polymeric NAD derivatives for lactate, yeast alcohol and horse liver alcohol dehydrogenases decreased with the increase in the NAD density of the polymer, and the lactate dehydrogenase showed no activity for the polymeric NAD derivatives with NAD densities of 2 x 10(-3) and 1 x 10(-2) mol/mol acrylamide polymerized. The polymeric NAD derivatives inhibited the activities of lactate and yeast alcohol dehydrogenases but did not inhibit those of horse liver alcohol and malate dehydrogenases. The polymeric NAD derivatives were competitive inhibitors with respect to NAD for the reaction of lactate dehydrogenase: the inhibition constant decreased from 2.2 microM to 0.02 microM with the increase in the NAD density from 4 x 10(-4) to 1 x 10(-2) mol/mol acrylamide polymerized.

Acrylic Resins↗
PubMed1985

Purification and characterization of a protein from chicken gizzard, which inhibits actin polymerization.

An actin-polymerization-inhibiting protein, that occurs in crude preparations of vinculin from chicken gizzard, has been purified by DEAE-cellulose and carboxymethyl ion-exchange chromatography. According to sodium dodecyl sulfate (SDS)/polyacrylamide gel electrophoresis and to gel filtration the polymerization-inhibiting protein is heterogeneous and the molecular mass ranges from 20 kDa to 80 kDa. After treatment with acid the polymerization-inhibiting activity was found to migrate on a SDS/polyacrylamide gel as a single band of molecular mass about 32 kDa. The mechanism of the action of the polymerization-inhibiting protein on actin assembly was investigated by the effect on the kinetics of actin polymerization. The polymerization-inhibiting protein blocks elongation of actin filaments at substoichiometric ratios but does not nucleate actin filaments. The equilibrium constant for binding of the polymerization-inhibiting protein to the barbed end of an actin filament was estimated to be 2 X 10(6) M-1 in 100 mM KCl and 2 mM MgCl2, and 35 X 10(6) M-1 in 2 mM MgCl2.

Actin Depolymerizing Factors↗
PubMed1998

Polymeric chitosan-based vesicles for drug delivery.

A simple carbohydrate polymer glycol chitosan (degree of polymerization 800 approx.) has been investigated for its ability to form polymeric vesicle drug carriers. The attachment of hydrophobic groups to glycol chitosan should yield an amphiphilic polymer capable of self-assembly into vesicles. Chitosan is used because the membrane-penetration enhancement of chitosan polymers offers the possibility of fabricating a drug delivery system suitable for the oral and intranasal administration of gut-labile molecules. Glycol chitosan modified by attachment of a strategic number of fatty acid pendant groups (11-16 mol%) assembles into unilamellar polymeric vesicles in the presence of cholesterol. These polymeric vesicles are found to be biocompatible and haemocompatible and capable of entrapping water-soluble drugs. By use of an ammonium sulphate gradient bleomycin (MW 1400), for example, can be efficiently loaded on to these polymeric vesicles to yield a bleomycin-to-polymer ratio of 0.5 units mg(-1). Previously polymers were thought to assemble into vesicles only if the polymer backbone was separated from the membrane-forming amphiphile by a hydrophilic side-arm spacer. The hydrophilic spacer was thought to be necessary to decouple the random motion of the polymer backbone from the ordered amphiphiles that make up the vesicle membrane. However, stable polymeric vesicles for use in drug delivery have been prepared from a modified carbohydrate polymer, palmitoyl glycol chitosan, without this specific architecture. These polymeric vesicles efficiently entrap water-soluble drugs.

Biocompatible Materials↗