Pendant Carboxyl Research Articles

Electrochemical Impedance Analysis of Biofunctionalized Conducting Polymer-Modified Graphene-CNTs Nanocomposite for Protein Detection

We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen (cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, anti-troponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection. The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1 Hz, which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61 (n = 0.61), whereas, it is 0.88 (n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic (Ret) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL−1–10.0 ng mL−1. The sensitivity of the transducer is 167.8 ± 14.2 Ω cm2 per decade, and it also exhibits high specificity and good reproducibility.

Preparation and properties of crosslinked hybrid proton exchange membrane based on sulfonated poly (arylene ether nitrile) with improved selectivity for fuel cell application

Novel sulfonated poly (arylene ether nitrile) with pendant carboxylic group copolymers have been prepared as proton exchange membranes which were applied in direct methanol fuel cells (DMFCs). Compared with others, this work shows two main advantages: the crosslinked method is uncomplicated and the membranes were prepared via the hydroquinonesulfonic acid potassium salt (SHQ) as crosslinker mingled in sulfonated poly (arylene ether nitrile) (SPEN) to avoid the decrease of proton conductivity. The obtained crosslinked membranes exhibited improved dimensional stability; larger tensile strength than that of pure SPEN; and good thermal, mechanical properties. Furthermore, after crosslinking, the membranes had low methanol permeability values (0.78–3.4 × 10−7 cm2 s−1) and displayed good proton conductivities in the range of 0.0328–0.0385 S·cm−1 at room temperature. The sample of SPEN-SHQ-5 % showed highest selectivity value of 4.205 × 105 S·s cm−3, which was 11.9 times higher than that of Nafion 117. All of these results indicated that these membranes would be the potential candidates as proton exchange membranes (PEMs) in DMFCs.

Thermal and Dielectric Behavior Studies of Poly(Arylene Ether Sulfone)s with Sulfonated and Phosphonated Pendants

The present paper discusses the aspects of the synthesizing valeric acid based poly(ether sulfone)s with active carboxylic acid pendants (VALPSU) from solution polymerization technique via nucleophilic displacement polycondensation reaction among 4,4′-dichlorodiphenyl sulfone (DCDPS) and 4,4′-bis(4-hydroxyphenyl) valeric acid (BHPA). The conditions necessary to synthesize and purify the polymer were investigated in some detail. The synthesized poly(ether sulfone)s comprise sulfone and ether linkages in addition to reactive carboxylic acid functionality; these active carboxylic acid functional groups were exploited to hold the phenyl sulphonic acid and phenyl phosphonic acid pendants. The phenyl sulphonic acid pendants in VALPSU were easily constructed by altering active carboxylic acid moieties by sulfanilic acid using N,N′-dicyclohexylcarbodiimide (DCC) mediated mild synthetic route, whereas the latter one was built in two steps. Initially, polyphosphoric acid condensation with VALPSU by 4-bromoaniline and next straightforward palladium catalyzed synthetic route, in both of which acidic pendants are clenched by polymer backbone via amide linkage. Without impairing the primary polymeric backbone modified polymers were prepared by varying the stoichiometric ratios of respective combinations. All the polymers were physicochemically characterized and pressed into tablets; electrical contacts were established to study the dielectric properties. Finally, the influence of the acidic pendants on the dielectric properties was examined.

Pendant dual sulfonated poly(arylene ether ketone) proton exchange membranes for fuel cell application

Abstract Poly(arylene ether ketone) (PAEK) possessing carboxylic groups at the pendant position is synthesized, and the substitution degree of pendant carboxylic groups is controlled by adjusting the ratio of 4,4-bis(4-hydroxyphenyl)valeric acid and 2,2-bis(4-hydroxyphenyl)propane. Dual sulfonated 3,3-diphenylpropylamine (SDPA) is grafted onto PAEK as a proton-conducting moiety via the amidation reaction with carboxylic groups. The transparent and flexible membranes with different degrees of sulfonation are fabricated so that we can test and compare their structure and properties with a commercial Nafion ® 115 membrane for PEMFC applications. All prepared PAEK-SDPA membranes exhibit good oxidative and hydrolytic stability from Fenton's and high temperature water immersion test. SAXS analysis illustrates an excellent phase separation between the hydrophobic backbone and hydrophilic pendant groups, resulting in big ionic clusters. The proton conductivity was measured at different relative humidity, and its behavior was analyzed by hydration number of the membrane. Among a series of membranes, some samples (including B20V80-SDPA) show not only higher proton conductivity, but also higher integrated cell performance than those of Nafion ® 115 at 100% relative humidity, and thus we expect these to be good candidate membranes for proton exchange membrane fuel cells (PEMFCs).

A new entry to synthesis of neocryptolepine related skeletons. An unexpected behavior of 3-acety-2-ethoxyindole and isatins

An unexpected and intriguing reaction to the direct construction of indolo[2,3-b]quinoline ring system of neocryptolepine analogues was discovered through simple heating of 3-acetyl-2-ethoxyindole with isatins in 10% aqueous ethanol media with the presence of KOH as the base. The process is very clean and avoids the use of toxic organic solvent, thereby enhancing the greenness of the transformation. Moreover, the newly-synthesized compounds bearing a pendant carboxyl group at the C-11 position of indolo[2,3-b]quinoline skeleton could be potentially applied as useful synthetic building blocks for more complex indolo[2,3-b]quinoline alkaloid derivatives.

Synthesis, structure and stability of a chiral imine-based Schiff-based ligand derived from L-glutamic acid and its [Cu4] complex

Studies of the stability of a ligand derived from L-glutamic acid and ortho-vanillin and its new [Cu4] complex are presented. The [Cu4] complex contains a heterocubane [CuII4O4] core and pendant carboxylic groups increasing its solubility in water, also under basic conditions. The stability of the complex in different solvents is confirmed with ESI-MS studies and such experiments as successful recrystallization. The complex is stable also under physiological conditions whereas the ligand is partly decomposed to L-glutamic acid and ortho-vanillin.

Carboxylate-Functionalized Mesoionic Carbene Precursors: Decarboxylation, Ruthenium Bonding, and Catalytic Activity in Hydrogen Transfer Reactions

Metalation of a carboxylate-functionalized pyridyl-triazolium salt containing a N1-bound pyridyl substituent either by direct means with [RuCl2(cymene)]2 or via a transmetalation procedure involving Ag2O and [RuCl2(cymene)]2 induces rapid decarboxylation without concomitant metalation. Subsequent metalation of the formed C4- and C5-unsubstituted triazolium salt is selective and occurs at the C4 position, i.e. remote from the pyridyl substituent, when the reaction is under kinetic control and at the C5 position adjacent to the pyridyl group, when the reaction is performed under thermodynamic control. Preservation of the carboxylate functional group in the complex is achieved when the corresponding ester-functionalized pyridyl-triazolium salt is metalated first and then subjected to ester hydrolysis. The formed complex contains a N,C-bidentate chelating pyridyl-triazolylidene ligand with a pendant carboxylate unit that is not coordinating to the metal center. These new triazolylidene ruthenium complexes sho...

Functionalization of emissive conjugated polymer nanoparticles by coprecipitation: consequences for particle photophysics and colloidal properties

The functionalization of polyfluorene (PFO) nanoparticles by coprecipitation of the conjugated polymer with an amphiphilic comb polymer, consisting of a hydrophobic polystyrene backbone with hydrophilic, carboxylic acid-terminated polyethylene oxide side-chains (PS-PEG-COOH), is investigated. The comb polymer affects the properties of the formed hybrid nanoparticles. Non-functionalized particles are typically larger (28 nm) than functionalized ones (20 nm); peak molar extinction coefficients are found to differ in a similar trend. Zeta potentials are negative, consistent with negative surface charge on PFO particles due to chemical defect formation, with additional charge on functionalized particles due to the pendant carboxylic acid groups. Emission quantum yields of functionalized particles are typically larger, consistent with lower efficiency of energy transfer to quenchers in smaller particles and weaker PFO interchain interactions due to chain dilution. The trend in per-particle fluorescence brightness values, as confirmed by single particle fluorescence imaging, reflects the nanoparticle extinction coefficients. Photostability studies on aqueous dispersions of hybrid particles indicate mild photobrightening under continuous illumination while PFO particles exhibit slow exponential emission decay. Functionalized particles are also resistant to aggregation during exposure to adenocarcinoma cells. Generally, the hybrid particles exhibit more favorable time-, pH- and medium-dependent stabilities, likely due to steric and electrostatic stabilization by PEG-carboxylic acid functionalities. Overall, the functionalized particles exhibit attractive properties: Reasonably small size, tight size distribution, high absorption cross section, radiative rate and emission quantum yield, excellent brightness and photostability, and good colloidal stability.

Complexation of Bi3+, Ac3+, Y3+, Lu3+, La3+and Eu3+with benzo-diaza-crown ether with carboxylic pendant arms

AbstractPolyaminopolycarboxylates are attractive ligands for binding cationic radionuclides for synthesis of radiopharmaceuticals with target delivery to tumor cells. Nowadays beta emitting Y−90 and Lu−177 are used as therapeutic agents, while Ac−225 and Bi−213 are considered as perspective for alpha therapy. In the present study new data on complexation of Y3+, Lu3+, Ac3+and Bi3+with 2,2’-(15-formyl-2,3,5,6,8,9,11,12-octahydrobenzo [b][1,4,10,7,13]trioxadiazacyclopentadecine-4,10- diyl)diacetic acid are presented. For ligand and complexes characterization potentiometric titration, solvent extraction, chromatography and solubility techniques were applied. The highest values of stability constants within the range of logK= 5.8 – 7.5 were found for Ac3+and REE. Fast complex formation is established which is beneficial for practical applications in radiopharmaceutical synthesis.

Ultrasound Assisted Synthesis and Characterization of Polyurethane for Coating Applications

Objectives: Exceptional reaction conditions can be generated by ultrasonic irradiation via acoustic cavitation, which allows for the synthesis of new materials with unusual properties. Inspired by the importance of this efficient and environmentally friendly synthetic route, waterborne polyurethane copolymer with pendant carboxylate in the hard segment is prepared. In this current attempt, 2,2-bis(hydroxymethyl)-propionic acid was used to incorporate ionic groups into polyurethane polymer. Methods/Analysis: Factors affecting the sonochemical polymerization such acoustic power, type of solvent, using of catalyst, and monomers molar ratio were studied. The prepared waterborne polyurethanes were investigated by FTIR and GPC. Furthermore, in the construction of surfaces, the influence of the application of prepared waterborne polyurethane on the interaction of polyester fabrics with methylene blue as cationic dyes was assessed. For that purpose, color strength and fastness tests were carried out to prove the effectiveness of surface modification. Findings: The results indicated that the one-shot sonochemical polymerization by ultrasound at 100 W was more effective in N,Ndimethyl formamide (DMF) than thermally assisted polyurethane polymerization. Novelty/Improvement: The rate of sonochemical polymerization is much faster than thermal polymerization. Improvement in the printability of PET fabrics treated with the prepared polyurethanes.

Nanoparticle chemisorption printing technique for conductive silver patterning with submicron resolution.

Silver nanocolloid, a dense suspension of ligand-encapsulated silver nanoparticles, is an important material for printing-based device production technologies. However, printed conductive patterns of sufficiently high quality and resolution for industrial products have not yet been achieved, as the use of conventional printing techniques is severely limiting. Here we report a printing technique to manufacture ultrafine conductive patterns utilizing the exclusive chemisorption phenomenon of weakly encapsulated silver nanoparticles on a photoactivated surface. The process includes masked irradiation of vacuum ultraviolet light on an amorphous perfluorinated polymer layer to photoactivate the surface with pendant carboxylate groups, and subsequent coating of alkylamine-encapsulated silver nanocolloids, which causes amine–carboxylate conversion to trigger the spontaneous formation of a self-fused solid silver layer. The technique can produce silver patterns of submicron fineness adhered strongly to substrates, thus enabling manufacture of flexible transparent conductive sheets. This printing technique could replace conventional vacuum- and photolithography-based device processing.

Stimuli Responsive Self‐Assembly of 3‐(Octyloxy)‐3‐Oxopropyl Acrylate‐Co‐Acrylic Acid Polymer in Aqueous Media

AbstractA novel copolymer based on 3‐(alkyloxy)‐3‐oxopropyl acrylate and acrylic acid was synthesized and characterized. Surface tension and fluorescence probe techniques (using N‐phenyl‐1‐naphthylamine as a probe) were employed to evaluate the surface properties of the amphiphilic copolymer. The copolymer was found to reduce the surface tension of water to 40–46 mN/m depending on the pH of the medium. The critical aggregation concentration of the copolymer determined by surface tension measurements was found to be 0.28 mg/ml at pH 4, 1.13 mg/ml at pH 8, and 1.44 mg/ml at pH 10, very close to those obtained by steady state fluorescence probe techniques (0.21, 1.13 and 1.48 mg/ml, respectively, at pH 4, 8, and 10). The pH‐induced structural transitions of the copolymer were also studied using steady state fluorescence with pyrene and 1,6‐diphenyl‐1,3,5‐hexatriene as probes, dynamic light scattering and transmission electron microscopy. The protonation of pendant carboxylate groups at acidic pH makes the aggregate compact and rigid. Conversely, ionization of the carboxylate groups under alkaline conditions resulted in larger aggregates.

Environmentally Benign CO2-Based Copolymers: Degradable Polycarbonates Derived from Dihydroxybutyric Acid and Their Platinum-Polymer Conjugates.

(S)-3,4-Dihydroxybutyric acid ((S)-3,4-DHBA), an endogenous straight chain fatty acid, is a normal human urinary metabolite and can be obtained as a valuable chiral biomass for synthesizing statin-class drugs. Hence, its epoxide derivatives should serve as promising monomers for producing biocompatible polymers via alternating copolymerization with carbon dioxide. In this report, we demonstrate the production of poly(tert-butyl 3,4-dihydroxybutanoate carbonate) from racemic-tert-butyl 3,4-epoxybutanoate (rac-(t)Bu 3,4-EB) and CO2 using bifunctional cobalt(III) salen catalysts. The copolymer exhibited greater than 99% carbonate linkages, 100% head-to-tail regioselectivity, and a glass-transition temperature (Tg) of 37 °C. By way of comparison, the similarly derived polycarbonate from the sterically less congested monomer, methyl 3,4-epoxybutanoate, displayed 91.8% head-to-tail content and a lower Tg of 18 °C. The tert-butyl protecting group of the pendant carboxylate group was removed using trifluoroacetic acid to afford poly(3,4-dihydroxybutyric acid carbonate). Depolymerization of poly(tert-butyl 3,4-dihydroxybutanoate carbonate) in the presence of strong base results in a stepwise unzipping of the polymer chain to yield the corresponding cyclic carbonate. Furthermore, the full degradation of the acetyl-capped poly(potassium 3,4-dihydroxybutyrate carbonate) resulted in formation of the biomasses, β-hydroxy-γ-butyrolacetone and 3,4-dihydroxybutyrate, in water (pH = 8) at 37 °C. In addition, water-soluble platinum-polymer conjugates were synthesized with platinum loading of 21.3-29.5%, suggesting poly(3,4-dihydroxybutyric acid carbonate) and related derivatives may serve as platinum drug delivery carriers.

A Novel Acetylcholinesterase Biosensor: Core–Shell Magnetic Nanoparticles Incorporating a Conjugated Polymer for the Detection of Organophosphorus Pesticides

To construct a sensing interface, in the present work, a conjugated polymer and core-shell magnetic nanoparticle containing biosensor was constructed for the pesticide analysis. The monomer 4,7-di(furan-2-yl)benzo[c][1,2,5]thiadiazole (FBThF) and core-shell magnetic nanoparticles were designed and synthesized for fabrication of the biosensing device. The magnetic nanoparticles were first treated with silica and then modified using carboxyl groups, which enabled binding of the biomolecules covalently. For the construction of the proposed sensor a two-step procedure was performed. First, the poly(FBThF) was electrochemically generated on the electrode surface. Then, carboxyl group modified magnetic nanoparticles (f-MNPs) and acetylcholinesterase (AChE), the model enzyme, were co-immobilized on the polymer-coated surface. Thereby, a robust and novel surface, conjugated polymer bearing magnetic nanoparticles with pendant carboxyl groups, was constructed, which was characterized using Fourier transform infrared spectrometer, cyclic voltammetry, scanning electron microscopy, and contact angle measurements. This novel architecture was then applied as an immobilization platform to detect pesticides. To the best of our knowledge, a sensor design that combines both conjugated polymer and magnetic nanoparticles was attempted for the first time, and this approach resulted in improved biosensor characteristics. Hence, this approach opens a new perspective in the field of enzyme immobilization and sensing applications. Paraoxon and trichlorfon were selected as the model toxicants. To obtain best biosensor performance, optimization studies were performed. Under optimized conditions, the biosensor in concern revealed a rapid response (5 s), a low detection limit (6.66 × 10(-3) mM), and high sensitivity (45.01 μA mM(-1) cm(-2)). The KM(app) value of poly(FBThF)/f-MNPs/AChE were determined as 0.73 mM. Furthermore, there was no considerable activity loss for 10 d for poly(FBThF)/f-MNPs/AChE biofilm.

CB-TE2A(+)·Cl(-)·3H2O: a short intermolecular hydrogen bond between zwitterionic bicyclo[6.6.2]tetraamine macrocycles.

1,4,8,11-Tetraazabicyclo[6.6.2]hexadecane-4,11-diacetic acid (CB-TE2A) is of much interest in nuclear medicine for its ability to form copper complexes that are kinetically inert, which is beneficial in vivo to minimize the loss of radioactive copper. The structural chemistry of the hydrated HCl salt of CB-TE2A, namely 11-carboxymethyl-1,8-tetraaza-4,11-diazoniabicyclo[6.6.2]hexadecane-4-acetate chloride trihydrate, C16H31N4O4(+)·Cl(-)·3H2O, is described. The compound crystallized as a positively charged zwitterion with a chloride counter-ion. Two of the amine groups in the macrocyclic ring are protonated. Formally, a single negative charge is shared between two of the carboxylic acid groups, while one chloride ion balances the charge. Two intramolecular hydrogen bonds are observed between adjacent pairs of N atoms of the macrocycle. Two intramolecular hydrogen bonds are also observed between the protonated amine groups and the pendant carboxylate groups. A short intermolecular hydrogen bond is observed between two partially negatively charged O atoms on adjacent macrocycles. The result is a one-dimensional polymeric zigzag chain that propagates parallel to the crystallographic a direction. A second intermolecular interaction is a hydrogen-bonding network in the crystallographic b direction. The carbonyl group of one macrocycle is connected through the three water molecules of hydration to the carbonyl group of another macrocycle.

Synthesis of Functional Polyester Based on Polylactic Acid and Its Effect on PC12 Cells after Coupling with Small Peptides

Polyesters containing functional groups are a suitable candidate matrix for cell culture in tissue engineering. Three types of semicrystalline copolymer poly(L-lactide-co-β-malic acid) [P(LA-co-BMD)] with pendent carboxyl groups were synthesized in this study. The functional monomer 3(S)-[(benzyloxycarbonyl)methyl]-1,4-dioxane-2,5-dione (BMD) was synthesized usingL-aspartic acid. The copolymer P(LA-co-BMD) was then synthesized through ring-opening copolymerization ofL-LA and BMD, with dodecanol as initiator and stannous octoate as catalyst. Copolymer structure was characterized by1H nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) analyses. Results of1H NMR and GPC analyses showed that the copolymers were synthesized successfully. DSC curves showed that the crystal melting peak and enthalpy decreased with increased BMD. The crystallinity of the copolymer was destroyed by the presence of the functional monomer. After deprotection, carboxyl groups were coupled with the isoleucine-lysine-valine-alanine-valine peptide throughN-hydroxysuccinimide/dicyclohexylcarbodiimide method. The small peptide was beneficial to the axon growth of PC12 cells.

Methoxy poly (ethylene glycol)-block-poly (glutamic acid)-graft-6-(2-nitroimidazole) hexyl amine nanoparticles for potential hypoxia-responsive delivery of doxorubicin

Tumor microenvironment-responsive nano drug delivery vehicles are gaining mounting attention in the field of biomedical sciences. The hypoxic response of the tumorous cells due to very low partial pressure of oxygen (some time less than 2.5 mm of Hg) in the tumor tissues makes hypoxia-responsive drug delivery system as the more appealing in cancer chemotherapy. Based on these considerations, we synthesized hypoxia-responsive polymeric materials methoxy poly (ethylene glycol)-block-poly (glutamic acid)-graft-6-(2-nitroimidazole) hexyl amine (mPEG-b-PLG-g-NID) by conjugation of the hydrophobic nitro imidazole derivative (NID)[6-(2-nitroimidazole) hexyl amine] with the pendant carboxylic group of poly (ethylene glycol)-block-poly (L-glutamic acid)(mPEG-b-PLG). The structure and degree of substitution were confirmed by proton NMR, FTIR, and UV–Vis spectroscopy. The degree of substitution was found to enhance with the increase in NID to polymer ratio. The hypoxia response of the material was evaluated by UV–Vis spectroscopy and zeta potential measurements. Doxorubicin was hydrophobically encapsulated in the micellar core of the hypoxia-responsive nanoparticles. The drug-loaded micelles showed faster release in hypoxic condition as compared to normoxic conditions. Moreover, the developed polymeric system was found non-toxic to MCF-7 cell line, thus suggesting its biocompatibility and suitability as drug delivery device.

PEG–PLGA copolymers bearing carboxylated side chains: Novel hydrogels with enhanced crosslinking via ionic interactions

ABSTRACTNovel water‐soluble amphiphilic block copolymers with pendant carboxylic acid groups are synthesized and used for the preparation of ionically crosslinked hydrogels. d,l‐Lactide (DLLA) and l−3‐(2‐benzyloxycarbonyl)ethyl‐1,4‐dioxane‐2,5‐dione (BED) are copolymerized at different ratios via organo‐catalyzed ring‐opening polymerization using a hydroxyl‐terminated poly(ethylene glycol) (PEG–OH) macroinitiator. Dynamic light‐scattering experiments show that, at low concentrations, aqueous solutions of these PEG‐P(BED‐DLLA) copolymers form micelles and aggregates. At higher concentrations, thermo‐sensitive gels are obtained, exhibiting a reversible gel‐to‐sol transition upon a temperature increase. Ionic interactions between the COOH groups and metal ions (Cu2+ or Ca2+) are shown to significantly shift the gel–sol transition to higher temperatures. Thus, the introduction of COOH groups significantly enhances the water solubility of the amphiphilic PEG–polyester copolymer and allows additional crosslinking interactions to form functionalized hydrogels with improved physical properties, making this new class of hydrogels interesting for various applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1222–1227

Properties and morphology study of proton exchange membranes fabricated from the pendant sulfonated poly(arylene ether ketone) copolymers composed of hydrophobic and hydrophilic multi-blocks for fuel cell

Polymer electrolyte membranes are prepared from poly(arylene ether ketone) composed of hydrophobic and hydrophilic multi-blocks. 4,4′-bis(4-hydroxyphenyl)-valeric acid and 4,4′-difluorobenzophenone are used for the synthesis of hydrophilic oligomers, while bisphenol A and 4,4′-difluorobenzophenone are used for hydrophobic oligomers. The proton conducting property is provided by sulfonation of the pendant carboxylic groups in hydrophilic blocks. The chemical structure of the oligomers and polymer synthesized is identified using 1H- and 19F- nuclear magnetic resonance (NMR) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopies as well as gel permeation chromatography (GPC). The development of distinguished hydrophobic-hydrophilic phase separation is confirmed by small-angle X-ray scattering (SAXS) spectroscopy and atomic force microscope (AFM). The thermal, mechanical, and chemical stabilities are endowed by the hydrophobic segment, whereas the proton conducting and water uptake properties are provided by the hydrophilic segment. The proton conductivity of the prepared membrane is comparable to that of Nafion 115 when the hydrophobic and hydrophilic block molecular weights are 3000 g mol−1 and 18,000 g mol−1, respectively. The block length effect on the membrane properties can be explained by the ion cluster dimension and structure examined by SAXS and AFM.

Micellar formulation of indocyanine green for phototherapy of melanoma

Phototherapy (PT), a light activated treatment modality, is a potential therapeutic option for the treatment of melanoma. In spite of the excellent safety profile and absorption in the near infrared (NIR) range, clinical potential of indocyanine green (ICG) as PT is limited by its short half-life and inefficient tumor accumulation. In this study, we have covalently conjugated ICG-NH2 to the pendant carboxyl groups of poly (ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate) (PEG-PCC) copolymer using carbodiimide coupling, which self-assembled into micelles with a particle size of 30–50nm and high ICG loading. These ICG conjugated micelles exhibited significant in vitro photodynamic cytotoxicity. Use of sodium azide and NIR radiation at 4°C revealed photodynamic and photothermal as mechanism of cytotoxicity of ICG solution and ICG conjugated micelles, respectively. In vivo NIR imaging demonstrated that ICG conjugated micelles prolonged its circulation and increased tumor accumulation through enhanced permeability and retention (EPR) effect. Enhanced tumor accumulation improved therapeutic efficacy with complete tumor regression in NIR irradiated ICG conjugated micelles compared to ICG solution and control in a A375 human melanoma tumor model in athymic nude mice. These results suggest that ICG conjugated micelles can be potentially utilized for PT and imaging of melanoma.