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As pivotal role of scaffold in tissue engineering (TE), the aim of present study was to design and development of extracellular matrix (ECM)-mimetic electrically conductive nanofibrous scaffolds composed of polyaniline-grafted tragacanth gum (TG-g-PANI) and poly(vinyl alcohol) (PVA) with different PANI content for skin tissue engineering (STE) application. The fabricated scaffolds were preliminary evaluated in terms of some physicochemical and biological properties. Cytocompatibility and cells proliferation properties of the scaffolds were examined with the well-known MTT assay, and it was found that the developed scaffolds have proper cytocompatibilities and can enhances the mouse fibroblast L929 cells adhesion as well as proliferation, which confirm their potential for STE applications. Hemocompatibility assay revealed that the hemolysis rate of the fabricated scaffolds were <2 % even at a relatively high concentration (200 μgmL -1 ) of samples, therefore, these scaffolds can be considered as safe. Human serum albumin (HSA) protein adsorption capacities of the fabricated scaffolds were quantified as 42 and 49 μgmg -1 that represent suitable values for a successful TE. Overall, the fabricated scaffold with 20 wt% of TG-g-PANI showed higher potential in both physicochemical and biological features than scaffold with 30 wt% of mentioned copolymer for STE application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2023 Elsevier B.V. All rights reserved.)

A dual stimuli-responsive magnetic nanohydrogel was fabricated as a potent drug delivery system (DDS) for 'smart' treatment of cancer by chemo/hyperthermia approach. For this objective, Fe 3 O 4 nanoparticles (NPs) were produced via a co-precipitation approach and then modified by 3-(trimethoxysilyl) propylmethacrylate (MPS) moiety. The modified NPs were copolymerized with N , N '-(dimethylamino)ethyl methacrylate (DMAEMA), and maleic anhydride (MA) monomers by a free radical polymerization approach to afford a Fe 3 O 4 @P(DMAEMA- co -MA) core-shell NPs. Afterward, the NPs were shell crosslinked by the reaction of anhydride unites with neutralized cystamine (Cys). The fabricated pH- and reduction-responsive magnetic nanohydrogel was physically loaded with methotrexate (MTX), as an anticancer drug, and its drug loading efficiency (LE) was calculated as 64 ± 2.7%. The developed nanohydrogel/MTX exhibited proper stimuli-triggered drug release behavior that qualified it as an efficient DDS according to the abnormal micro-environment of cancerous tumors. The anticancer activity investigation using chemo/hyperthermia therapy approach by MTT-assay revealed that the nanohydrogel/MTX might show better clinical outcomes than those of the free MTX.

In this study a novel pH-responsive magnetic nanocomposite based on reduced graphene oxide was developed for combination of doxorubicin (Dox)-cisplatin (Cis) delivery to destroy the MCF-7 cell line. For this purpose, polyhydroxyethyl methacrylate (PHEMA) was bonded to the reduced graphene oxide through ATRP polymerization using grafting from method. Then the PHEMA hydroxy groups were converted to succinyloxy groups by polyesterification with succinic anhydride. The physicochemical properties of the nanocomposite were investigated via FTIR, SEM, XRD, DLS and TGA analysis. Unique structure of nanocomposite led to simultaneous encapsulation of Dox (75%) and Cis (82%) through ionic interaction, π-π stacking and hydrogen bonding. The obtained nanocomposite was uptake by MCF-7 cells at early first hour because of nanocomposite small size (below 70 nm). Cell viability assay results revealed that the Dox&Cis-loaded nanocomposite showed the highest rate of MCF-7 cells at lowest concentration (IC50 = 0.798 µg/mL) compared to treatment groups received single drug-loaded nanocomposite and free drugs. Dox&Cis-loaded nanocomposite exhibited a synergistic influence with the combination index (CI) value <1. The cell cycle analysis results revealed that the highest amount of apoptosis (cells population in sub G1 was 75%) was observed in the Dox&Cis-loaded nanocomposite treatment group compared with the single drug-loaded nanocomposite and free drugs. Our findings confirmed that combinational therapy by Dox and Cis graphene oxide-based nanocomposite has increased the cytotoxicity in MCF-7 cells by stimulating the apoptotic response.

A novel multi-stimuli-responsive theranostic nanomedicine was designed and fabricated by the conjugation of a thiol end-capped poly( N -isopropylacrylamide- block -acrylic acid) (HS-PNIPAAm- b -PAA) onto Fe 3 O 4 @Au nanoparticles (NPs) followed by physical loading of doxorubicin hydrochloride (Dox) as a general anticancer drug. For this purpose, Fe 3 O 4 @Au NPs were fabricated through small Au nanolayer grown on larger magnetic NPs. A HS-PNIPAAm- b -PAA was synthesized through an atom transfer radical polymerization (ATRP) approach, and then conjugated with as-synthesized Fe 3 O 4 @Au NPs by Au-S bonding. The Dox loading capacity of the synthesized Fe 3 O 4 @Au/Polymer theranostic NPs was calculated to be 81%. The theranostic nanomedicine exhibited excellent in vitro drug release behavior under pH and thermal stimuli. The anticancer activity evaluation using MTT assay (against MCF7 cells) revealed that the fabricated Fe 3 O 4 @Au/Polymer has high potential as theranostic nanomedicine for cancer therapy of solid tumors. This nanosystem can also applied in photothermal therapy, hyperthermia therapy, and their combination with chemotherapy due to presence of gold and Fe 3 O 4 nanomaterials in its structure.

This study aimed to design and development of a magnetic natural hydrogel based on alginate (Alg), gelatin (Gel), and Fe 3 O 4 magnetic nanoparticles (MNPs) as an efficient and "smart" drug delivery system (DDS) for cancer therapy. First, Alg was partially oxidized (OAlg), and then the Alg-Gel chemical hydrogel was synthesized through "Shift-Base" condensation reaction. Afterward, Fe 3 O 4 NPs were incorporated into the hydrogel through in situ chemical co-precipitation approach. The scanning electron microscopy (SEM) image exhibited that the fabricated Alg-Gel hydrogel has porous microstructure without microphase separation. Transmission electron microscopy (TEM) revealed the well-defined formation of Fe 3 O 4 NPs throughout the Alg-Gel hydrogel with spherical shapes in the size range of 25 ± 10 nm. Saturation magnetization (δ s ) value of the Alg-Gel/Fe 3 O 4 was obtained to be 31 emu g -1 that represent proper magnetic property for "smart" drug delivery purposes. The obtained Alg-Gel/Fe 3 O 4 was loaded with doxorubicin hydrochloride (Dox), and its drug loading and encapsulation efficiencies as well as its anticancer activity was investigated against Hela cells. The formulated Alg-Gel/Fe 3 O 4 -Dox exhibited pH-dependent drug release behavior due to presence of carboxylic acid groups in the DDS. According to the results, the Alg-Gel/Fe 3 O 4 magnetic hydrogel can be considered as an efficient and "smart" DDS for cancer therapy and diagnosis., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2020. Published by Elsevier B.V.)

A novel electrically conductive nanofibrous scaffold based on polyaniline-co-(polydopamine-grafted-poly(d,l-lactide)) [PANI-co-(PDA-g-PLA)] was fabricated using electrospinning technique and its physicochemical as well as biological characteristics toward bone tissue engineering (TE) were investigated extensively. In detail, PANI-co-PDA was synthesized via a one-step chemical oxidization approach. Then, d,l-lactaide monomer was grafted onto PDA segment using a ring opening polymerization (ROP) to afford PANI-co-(PDA-g-PLA) terpolymer. The successful synthesis of PANI-co-(PDA-g-PLA) terpolymer was confirmed using FTIR spectroscopy as well as TGA analysis. Finally, a solution of the synthesized terpolymer was electrospun to fabricate a conductive nanofibrous scaffold. Some physicochemical features such as mechanical, conductivity, electroactivity, hydrophobicity, and morphology as well as biological characteristics including biocompatibility, biodegradability, as well as enhancing the cells adhesion and proliferation were investigated. According to the above-mentioned experimental results, the fabricated electrospun nanofibers can be considered as a potential scaffold for TE application, mainly due to its proper physicochemical and biological properties., Competing Interests: Note The authors declare no competing financial interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Nowadays, tissue and organ failures resulted from injury, aging accounts, diseases or other type of damages is one of the most important health problems with an increasing incidence worldwide. Current treatments have limitations including, low graft efficiency, shortage of donor organs, as well as immunological problems. In this context, tissue engineering (TE) was introduced as a novel and versatile approach for restoring tissue/organ function using living cells, scaffold and bioactive (macro-)molecules. Among these, scaffold as a three-dimensional (3D) support material, provide physical and chemical cues for seeding cells and has an essential role in cell missions. Among the wide verity of scaffolding materials, natural or synthetic biopolymers are the most commonly biomaterials mainly due to their unique physicochemical and biological features. In this context, naturally occurring biological macromolecules are particular of interest owing to their low immunogenicity, excellent biocompatibility and cytocompatibility, as well as antigenicity that qualified them as popular choices for scaffolding applications. In this review, we highlighted the potentials of natural and synthetic polymers as scaffolding materials. The properties, advantages, and disadvantages of both polymer types as well as the current status, challenges, and recent progresses regarding the application of them as scaffolding biomaterials are also discussed., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of this study was to developing two novel nanofibrous scaffolds composed of poly(ethylene glycol)-modified polypyrrole [PEG-b-(PPy) 4 ] and poly(ε-caprolactone) (PCL) for tissue engineering (TE) applications. For this purpose, pyrrole-functionalized PEGs AB 4 macromonomers (PyPEGsM) were synthesized through the Steglich esterification of PEGs ends-caped tetraol [PEGs(OH) 4 ] using pyrrole-2-carboxylic acid. These macromonomers were subsequently copolymerized with pyrrole monomer using chemical oxidation polymerization approach to produce PEGs-b-(PPy) 4 copolymers. A solution of PCL and the synthesized PEGs-b-(PPy) 4 copolymers were electrospun to fabricate uniform, conductive, and biocompatible nanofibrous scaffolds. The performances of the fabricated nanofibers as TE scaffolds were examined in terms of biological (biocompatibility and biodegradability) as well as physicochemical (electroactivity, conductivity, mechanical properties, and morphology) features. As the results, the fabricated electrospun nanofibers were found as proper scaffolds for use in TE applications that require electroactivity., (Copyright © 2018. Published by Elsevier B.V.)

Although the traditional hydrogels have shown great potential applications in designing drug delivery systems, the burst release of drugs remains an issue. In this work, we develop and evaluate a sustained release of ciprofloxacin using chitosan/hydroxyapatite/κ-carrageenan complexes. The size and structure of HA nanoparticles were characterized by X-ray diffraction, transmittance electron microscopy, and Fourier-transform infrared spectroscopy. The ciprofloxacin-loaded hydrogel nanocomposites exhibited antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. Due to the introduced HA, the release of ciprofloxacin occurred in a sustained release manner. While the pristine chitosan/κ-carrageenan complex released about 98% of ciprofloxacin during 120 h, only 52 and 66% of the loaded drug was released from hydrogel nanocomposites containing high and low content of HA, respectively. The sustained release of ciprofloxacin from the hydrogel nanocomposites identifies them as a potential candidate for designing drug delivery systems with prolonged release ability., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The main objective of this work was to develop κ-carrageenan-crosslinked magnetic chitosan with different molecular weights as pH-responsive carriers for controlled release of anticancer drug sunitinib. The characterization of magnetic carriers revealed that the size of magnetic nanoparticles is affected by the molecular weight of chitosan. Drug encapsulation efficiency and release performance influenced by the size of magnetic nanoparticles. Encapsulation efficiencies of sunitinib by low, medium and high molecular weights of magnetic chitosan carriers were found to be 62.38, 69.57 and 78.42%, respectively. The in vitro sunitinib release from magnetic chitosan/κ-carrageenan carriers was pH-dependent and followed a Fickian release mechanism. Sunitinib was efficiently released from magnetic carriers into environment under acidic pHs and the release rate was size- and molecular weight-dependent. The pH-dependent release of sunitinib with a minimal release content at pH = 7.4 makes the present magnetic carriers as promising candidate for anticancer drugs with reduced side effects., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A novel starch-based stimuli-responsive magnetite nanohydrogel (MNHG), namely Fe 3 O 4 -g-[poly(N-isopropylacrylamide-co-maleic anhydride)]@strach; Fe 3 O 4 -g-(PNIPAAm-co-PMA)@starch, was successfully developed for targeted delivery of doxorubicin (DOX) as an anticancer drug. First, magnetite nanoparticles (MNPs) was modified using chloroacetyl chloride moiety followed by grafting of NIPAAm and MA monomers through ATRP technique. The resultant Fe 3 O 4 -g-(PNIPAAm-co-PMA) nanocomposite was crosslinked through the reaction between the anhydride group of MA and hydroxyl groups of starch to afford a Fe 3 O 4 -g-(PNIPAAm-co-PMA)@starch MNHG. The chemical structure of the synthesized materials were confirmed using Fourier transform infrared (FTIR) spectroscopy. Furthermore, morphology, size, thermal property, and magnetic properties of the synthesized MNHG were studied. This MNHG was loaded with DOX, and drug loading and encapsulation efficiencies as well as pH- and temperature-responsive drug release behavior of the fabricated MNHG were also evaluated. As results, we envision that the developed MNHG has potential as de novo drug delivery system (DDS) due to its smart physicochemical features., (Copyright © 2018. Published by Elsevier B.V.)

This article evaluates the anticancer drug delivery performances of two nanohydrogels composed of poly(N-isopropylacrylamide-co-itaconic anhydride) [P(NIPAAm-co-IA)], poly(ethylene glycol) (PEG), and Fe 3 O 4 nanoparticles. For this purpose, the magnetite nanohydrogels (MNHGs) were loaded with doxorubicin hydrochloride (DOX) as a universal anticancer drug. The morphologies and magnetic properties of the DOX-loaded MNHGs were investigated using transmission electron microscopy (TEM) and vibrating-sample magnetometer (VSM), respectively. The sizes and zeta potentials (ξ) of the MNHGs and their corresponding DOX-loaded nanosystems were also investigated. The DOX-loaded MNHGs showed the highest drug release values at condition of 41 °C and pH 5.3. The drug-loaded MNHGs at physiological condition (pH 7.4 and 37 °C) exhibited negligible drug release values. In vitro cytotoxic effects of the DOX-loaded MNHGs were extensively evaluated through the assessing survival rate of HeLa cells using the MTT assay, and there in vitro cellular uptake into the mentioned cell line were examined using fluorescent microscopy and fluorescence-activated cell sorting (FACS) flow cytometry analyses. As the results, the DOX-loaded MNHG1 exhibited higher anticancer drug delivery performance in the terms of cytotoxic effect and in vitro cellular uptake. Thus, the developed MNHG1 can be considered as a promising de novo drug delivery system, in part due to its pH and thermal responsive drug release behavior as well as proper magnetite character toward targeted drug delivery.

Magnetic bioadsorbents based on chitosan with different molecular weights were prepared. To stabilize under acidic condition the synthesized magnetic chitosan was crosslinked with κ-carrageenan. The characterization of magnetic bioadsorbents revealed that the size of magnetic nanoparticles is affected by the chitosan molecular weight. Magnetic nanoparticles with larger sizes were obtained with the high molecular weight of chitosan. The removal of eriochrome black-T (EBT) by the magnetic bioadsorbents was investigated. The equilibrium adsorption isotherm data of EBT on bioadsorbents were found to be well explained through Langmuir isotherm model, from which the maximum adsorption capacities were found to be 280, 235, and 199mg/g for bioadsorbents prepared with low, medium, and high molecular weights of chitosan, respectively. A remarkable reduction in adsorption capacities of bioadsorbents was observed as the pH of dye solution was increased. The reduction in the dye adsorption under basic media suggested using a mild condition (pH=9) to recycle and reuse the bioadsorbents. Cyclic experiments indicated that current bioadsorbents can be effectively reused to remove anionic EBT from aqueous solutions. The removal efficiencies remained >93% even after five adsorption-desorption cycles, which suggest the present bioadsorbents as a great candidate in the wastewater treatment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, a novel thermo-responsive Fe 3 O 4 /poly(methylmethacrylate-b-N-isopropylacrylamide-b-acrylic acid) magnetic composite nanosphere was synthesized for anticancer drug delivery applications. For this propose, the poly(methylmethacrylate-b-N-isopropylacrylamide-b-acrylic acid) [poly (MMA-b-NIPAAm-b-AAc)] was synthesized via reversible addition-fragmentation transfer method. The physic-chemical characterization of the Fe 3 O 4 /poly(MMA-b-NIPAAm-b-AAc) magnetic composite nanosphere was investigated by FTIR, HNMR spectroscopies and GPC, FESEM, XRD, VSM and DLS. The thermo-sensitivity of the Fe 3 O 4 /P(MMA-b-NIPAAm-b-AAc) magnetic composite nanosphere was confirmed via DLS at 40 °C. DOX encapsulation efficiency was calculated to be 98.2%. The effect of temperature and pH on release behaviors of stimuli responsive DOX-loaded Fe 3 O 4 /P(MMA-b-NIPAAm-b-AAc)] magnetic composite nanosphere were investigated. The release rate at pH 7.4, 5.4 and 4 (T = 37 °C) was reached about 24.4, 42.4 and 57.5 wt%, after 4-5 day. The release rate improved at tumor simulated environment (t:40 °C and pH ≤ 5.4). The cytotoxic effects of the magnetic composite nanosphere were appraised by MTT assay and the results indicated that novel developed smart nanocomposite here was nontoxic to MCF-7 cells and can be applied as anti-cancer drug delivery system. Also, the results of the Cellular uptake of MCF7 cells treated with rhodamine labeled DOX-loaded nanocarrier for 2 h have indicated that DOX can be applied as cytotoxic agent and targeting ligand.

In this paper, an effective method was employed for preparation of nanofibers using conducting polymer-functionalized reduced graphene oxide (rGO). First, graphene oxide (GO) was obtained from graphite by Hommer method. GO was reduced to rGO by NaBH 4 and covalently functionalized with a 3-thiophene acetic acid (TAA) by an esterification reaction to reach 3-thiophene acetic acid-functionalized reduced graphene oxide macromonomer (rGO-f-TAAM). Afterward, rGO-f-TAAM was copolymerized with 3-dodecylthiophene (3DDT) and 3-thiophene ethanol (3TEt) to yield rGO-f-TAA-co-PDDT (rGO-g-PDDT) and rGO-f-TAA-co-P3TEt (rGO-g-PTEt), which were confirmed by Fourier transform infrared spectra. The grafted materials depicted better electrochemical properties and superior solubilities in organic solvents compared to GO and rGO. The soluble rGO-g-PDDT and rGO-g-PTEt composites blended with polycaprolactone were fabricated by electrospinning, and then cytotoxicity, hydrophilicity, biodegradability and mechanical properties were investigated. The grafted rGO composites exhibited a good electroactivity behavior, mainly because of the enhanced electrochemical performance. The electrospun nanofibers underwent degradation about 7 wt% after 40 days, and the fabricated scaffolds were not able to induce cytotoxicity in mouse osteoblast MC3T3-E1 cells. The soluble conducting composites developed in this study are utilizable in the fabrication of nanofibers with tissue engineering application.

The aim of this study was to synthesis and characterization of a novel stimuli-responsive polymeric nanosystem for theranostic applications. For this purpose, starch was modified by itaconic anhydride to afford an itaconat-functionalized starch macromonomer (starch-IA). This macromonomer with carboxylic functional groups was subsequently adsorbed onto the surface of iron oxide nanoparticles (Fe 3 O 4 NPs), and then copolymerized with N-isopropylacrylamide (NIPAAm) monomer via a 'free' radical initiated polymerization technique to produce a temperature-responsive magnetic nanohydrogel (MNHG). The chemical structures of all samples as representatives were characterized by means of Fourier transform infrared (FTIR) spectroscopy. The lower critical solution temperature (LCST), thermal responsibility, morphology, elemental composition, thermal stability, and magnetic properties of the synthesized MNHG were investigated. In addition, the methotrexate (MTX)-loading capacity (∼74%) and stimuli-responsive drug release ability of the synthesized MNHG were also evaluated. As results, we envision that the synthesized starch-g-PNIPAAm/Fe 3 O 4 MNHG may be find theranostic applications, in part due to its smart physicochemical properties., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A novel pH- and thermo-responsive ABC triblock copolymer {poly[(2-succinyloxyethyl methacrylate)-b-(N-isopropylacrylamide)-b-[(N-4-vinylbenzyl),N,N-diethylamine]]} [P(SEMA-b-NIPAAm-b-VEA)] was successfully synthesized via reversible addition of fragmentation chain transfer (RAFT) polymerization technique. The molecular weights of PHEMA, PNIPAAm, and PVEA segments in the synthesized triblock copolymer were calculated to be 10,670, 6140, and 9060gmol -1 , respectively, from proton nuclear magnetic resonance ( 1 H NMR) spectroscopy. The "schizophrenic" self-assembly behavior of the synthesized P(SEMA-b-NIPAAm-b-VEA) triblock copolymer under pH and thermal stimulus were investigated by means of 1 H NMR and ultraviolet-visible (UV-vis) spectroscopies as well as dynamic light scattering (DLS) and zeta potential (ξ) measurements. The doxorubicin hydrochloride (DOX)-loading capacity, and stimuli-responsive drug release ability of the synthesized triblock copolymer were also investigated. The biocompatibility of the synthesized triblock copolymer was confirmed through the assessing survival rate of breast cancer cell line (MCF7) using MTT assay. In contrast, DOX-loaded triblock copolymer exhibited an efficient anticancer performance in comparison with free DOX verified by MTT and DAPI staining assays. As the results, we envision that the synthesized P(SEMA-b-NIPAAm-b-VEA) triblock copolymer can be applied as an enhanced anticancer drug delivery nanosystem, mainly due to its smart physicochemical and biocompatibility properties., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A novel electrically conductive scaffold containing hyperbranched aliphatic polyester (HAP), polythiophene (PTh), and poly(ε-caprolactone) (PCL) for regenerative medicine application was succesfully fabricated via electrospinning technique. For this purpose, the HAP (G4; fourth generation) was synthesized via melt polycondensation reaction from tris(methylol)propane and 2,2-bis(methylol)propionic acid (bis-MPA). Afterward, the synthesized HAP was functionalized with 2-thiopheneacetic acid in the presence of N,N-dicyclohexyl carbodiimide, and N-hydroxysuccinimide as coupling agent and catalyst, respectively, to afford a thiophene-functionalized G4 macromonomer. This macromonomer was subsequently used in chemical oxidation copolymerization with thiophene monomer to produce a star-shaped PTh with G4 core (G4-PTh). The solution of the G4-PTh, and PCL was electrospun to produce uniform, conductive, and biocompatible nanofibers. The conductivity, hydrophilicity, and mechanical properties of these nanofibers were investigated. The biocompatibility of the electrospun nanofibers were evaluated by assessing the adhesion and proliferation of mouse osteoblast MC3T3-E1 cell line and in vitro degradability to demonstrate their potential uses as a tissue engineering scaffold. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2673-2684, 2016., (© 2016 Wiley Periodicals, Inc.)

This article describes the synthesis and characterization of a novel 'schizophrenic' diblock copolymer [poly(2-succinyloxyethyl methacrylate)- b -poly[( N -4-vinylbenzyl), N , N -diethylamine)]; PSEMA- b -PVEA] via reversible addition of fragmentation chain transfer (RAFT) polymerization technique. The chemical structures of all samples as representatives were characterized by means of Fourier transform infrared (FTIR), and 1 H nuclear magnetic resonance (NMR) spectroscopies. The molecular weights of PHEMA and PVEA segments were calculated to be 9770 and 12,630 gmol -1 , respectively, from 1 H NMR spectroscopy. The self-assembly behavior of the synthesized PSEMA- b -PVEA diblock copolymer was investigated by means of 1 H NMR spectroscopy, dynamic light scattering (DLS) measurements, and transmission electron microscopy (TEM) observation. The average sizes of the PSEMA- b -PVEA micelles at pHs 3.0, 6.0, and 10.0 were obtained to be 294, 237, and 201 nm, respectively, from DLS analysis. The zeta potential measurements at various pHs demonstrated that the synthesized PSEMA- b -PVEA diblock copolymer has zwitterionic properties, and the range of isoelectric point's (IEP's) was determined as 5.8-7.3. It is expected that the synthesized PSEMA- b -PVEA diblock copolymer considered as a prospective candidate in nanomedicine applications such as drug delivery, mainly due to its excellent 'schizophrenic' micellization behavior.

This study aims to explore an effective route for the preparation of conductive N -substituted polyaniline by incorporation of hexadecyl side chains into the fully reduced form of nano-structured polyaniline leucoemeraldine base. For this purpose, at first nano-structured emeraldine salt polyaniline was synthesized by interfacial chemical oxidative polymerization. The dark green product salt was neutralized by an ammonia solution in order to give us an emeraldine base (EB). Thereafter, the reduced form of nano-structured polyaniline was prepared by treating the obtained EB with phenylhydrazine in methanol. The excess amount of butyllithium was applied to abstract protons from the amine nitrogens of nano-structured LEB polyaniline chains. Thereafter, deprotonated polyaniline was reacted with hexadecylbromide to prepare poly( N- hexadecylaniline) through N -grafting reaction. The obtained poly( N- hexadecylaniline) was characterized using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry, and thermal gravimetry analysis (TGA). The average diameters of unsubstituted and substituted polyaniline particles were determined by particle size analyzer. The optical properties of the poly( N- hexadecylaniline) in the undoped and doped state were obtained using UV-vis spectroscopy and the electrical conductivity of the sample was measured using sample in which the conductive materials were sandwiched between two Ni electrodes at room temperature. Also, electroactivity of the synthesized polymer was investigated under cyclic voltammetric conditions on the surface of the working glassy carbon electrode. The solubility of the obtained polymer was examined in common organic solvents., (© 2012 Taylor & Francis.)