Intelligent anticancer drug delivery performances of two poly(N-isopropylacrylamide)-based magnetite nanohydrogels.

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 Fe3O4 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.

A comprehensive review on nanocomposite biomaterials based on gelatin for bone tissue engineering.

The creation of a suitable scaffold is a crucial step in the process of bone tissue engineering (BTE). The scaffold, acting as an artificial extracellular matrix, plays a significant role in determining the fate of cells by affecting their proliferation and differentiation in BTE. Therefore, careful consideration should be given to the fabrication approach and materials used for scaffold preparation. Natural polypeptides such as gelatin and collagen have been widely used for this purpose. The unique properties of nanoparticles, which vary depending on their size, charge, and physicochemical properties, have demonstrated potential in solving various challenges encountered in BTE. Therefore, nanocomposite biomaterials consisting of polymers and nanoparticles have been extensively used for BTE. Gelatin has also been utilized in combination with other nanomaterials to apply for this purpose. Composites of gelatin with various types of nanoparticles are particularly promising for creating scaffolds with superior biological and physicochemical properties. This review explores the use of nanocomposite biomaterials based on gelatin and various types of nanoparticles together for applications in bone tissue engineering.

Self-activating chitosan-based nanoparticles for sphingosin-1 phosphate modulator delivery and selective tumor therapy.

This study reports on the design and synthesis of hypoxia responsive nanoparticles (HRNPs) composed of methoxy polyethylene glycol-4,4 dicarboxylic azolinker-chitosan (mPEG-Azo-chitosan) as ideal drug delivery platform for Fingolimod (FTY720, F) delivery to achieve selective and highly enhanced TNBC therapy in vivo. Herein, HRNPs with an average size of 49.86 nm and a zeta potential of +3.22 mV were synthetized, which after PEG shedding can shift into a more positively-charged NPs (+30.3 mV), possessing self-activation ability under hypoxia situation in vitro, 2D and 3D culture. Treatment with lower doses of HRNPs@F significantly reduced MDA-MB-231 microtumor size to 15 %, induced apoptosis by 88 % within 72 h and reduced highly-proliferative 4 T1 tumor weight by 87.66 % vs. ∼30 % for Fingolimod compared to the untreated controls. To the best of our knowledge, this is the first record for development of hypoxia-responsive chitosan-based NPs with desirable physicochemical properties, and selective self-activation potential to generate highly-charged nanosized tumor-penetrating chitosan NPs. This formulation is capable of localized delivery of Fingolimod to the tumor core, minimizing its side effects while boosting its anti-tumor potential for eradication of TNBC solid tumors.

Extracellular matrix-mimetic electrically conductive nanofibrous scaffolds based on polyaniline-grafted tragacanth gum and poly(vinyl alcohol) for skin tissue engineering application.

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.

Stimuli-responsive natural gums-based drug delivery systems for cancer treatment.

Chemotherapy as the main cancer treatment method has non-specific effects and various side-effects. Accordingly, significant attempts have been conducted to enhance its efficacy through design and development of "smart" drug delivery systems (DDSs). In this context, natural gums, as a nice gift by the nature, can be exploited as stimuli-responsive DDSs for cancer treatment in part due to their renewability, availability, low cost, bioactivity, biocompatibility, low immunogenicity, biodegradability, and acceptable stability in both in vitro and in vivo conditions. However, some shortcomings (e.g., poor mechanical properties and high hydration rate) restrict their biomedical application ranges that can be circumvented through modification process (e.g., grafting of stimuli-responsive polymers or small molecules) to obtain tailored biomaterials. This review article aimed to compile the stimuli-responsive DDSs based on natural gums. In addition, different types of stimuli, the fundamental features of natural gums, as well as their chemical modification approaches are also shortly highlighted.

Preparation, physicochemical characterization, and anti-proliferative properties of Lawsone-loaded solid lipid nanoparticles.

Lawsone (LWS) is a naphthoquinone-type dye with potential antitumor activity. LWS is used in cosmetics for coloring hair, skin, and nails. In this study, solid lipid nanoparticles (SLNs) containing LWS were prepared using a hot homogenization technique. Physicochemical properties of LWS-SLNs including encapsulation efficiency (EE), drug loading (DL), size, zeta potential, homogeneity, in vitro release, and kinetics of release were determined. The potential cytotoxic properties of LWS-SLNs were investigated. Comet assay was done to assess the genotoxicity of LWS-SLNs. The scanning electron microscopy (SEM) images revealed that LWS-SLNs were spherical and homogeneously dispersed. The average diameter of free SLNs and LWS-SLNs were 97 ± 1.4 and 127 ± 3.1 nm, respectively with high EE% (95.88 ± 3.29) and a DL of 22.72 ± 1.39 mg/mL of LWS-SLNs. The plain LWS could induce growth inhibition of A549 cells with IC50 of 17.99 ± 1.11, 13.37 ± 1.22, and 9.21 ± 1.15 µg/mL after 24, 48, and 72 h, respectively, while LWS-SLNs had more cytotoxic effects after 48 h (9.81 ± 1.3 µg/mL). Comet assay represented clear fragmentation in the chromatin of the treated cells. Besides, LWS-SLNs (13.37 ± 1.22 µg/mL) induced ∼52 % apoptosis and even necrosis after 48 h. The qPCR results showed an enhanced downregulation of Bcl-2 and upregulation of Casp 9 due to the treatment of A549 cells with LSW-SLNs. In conclusion, a stable formulation of LWS-SLN was prepared with good physicochemical features and long-term biological effects that candidate it for in vivo trials.

Hyaluronic acid-based drug nanocarriers as a novel drug delivery system for cancer chemotherapy: A systematic review.

Chemotherapy is the most common treatment strategy for cancer patients. Nevertheless, limited drug delivery to cancer cells, intolerable toxicity, and multiple drug resistance are constant challenges of chemotherapy. Novel targeted drug delivery strategies by using nanoparticles have attracted much attention due to reducing side effects and increasing drug efficacy. Therefore, the most important outcome of this study is to answer the question of whether active targeted HA-based drug nanocarriers have a significant effect on improving drug delivery to cancer cells.This study aimed to systematically review studies on the use of hyaluronic acid (HA)-based nanocarriers for chemotherapy drugs. The two databases MagIran and SID from Persian databases as well as international databases PubMed, WoS, Scopus, Science Direct, Embase, as well as Google Scholar were searched for human studies and cell lines and/or xenograft mice published without time limit until 2020. Keywords used to search included Nanoparticle, chemotherapy, HA, Hyaluronic acid, traditional medicine, natural medicine, chemotherapeutic drugs, natural compound, cancer treatment, and cancer. The quality of the studies was assessed by the STROBE checklist. Finally, studies consistent with inclusion criteria and with medium- to high-quality were included in the systematic review.According to the findings of studies, active targeted HA-based drug nanocarriers showed a significant effect on improving drug delivery to cancer cells. Also, the use of lipid nanoparticles with a suitable coating of HA have been introduced as biocompatible drug carriers with high potential for targeted drug delivery to the target tissue without affecting other tissues and reducing side effects. Enhanced drug delivery, increased therapeutic efficacy, increased cytotoxicity and significant inhibition of tumor growth, as well as high potential for targeted chemotherapy are also reported to be benefits of using HA-based nanocarriers for tumors with increased expression of CD44 receptor.

Chemically Modified Natural Polymer-Based Theranostic Nanomedicines: Are They the Golden Gate toward a de Novo Clinical Approach against Cancer?

It is an unquestionable fact that cancer, also called malignancy, has or will soon become the major global health care problem with an increasing incidence worldwide. Conventional treatment approaches (e.g., radiation or chemotherapy) treat both cancerous and surrounding normal tissues simultaneously, which leads to a poor therapeutic effect on tumors and severe toxic side effects on healthy tissues. Considering these thematic issues, the design and development of more efficient treatment approaches is one of the most important demands of health care in the near future. In this context, the emergence of nanotechnology opens new opportunities for addressing the issues of conventional drug delivery systems (DDSs) for cancer therapy. Theranostic nanomedicines are indebted to the advent of nanotechnology and were introduced by Funkhouser in 2002. These nanomedicines are the newest DDSs that combine diagnostic and therapeutic properties into a single platform. Theranostic nanomedicines are generally composed of targeting agents, diagnostic tracers, effective drug(s), and biomaterial(s) as the matrix to the formulation. Among these, biomaterials have a pivotal role in theranostic nanomedicines due to their direct influence on the system effectiveness. In this context, natural polymers can be considered as potential candidates, mainly due to their inherent physicochemical as well as biological advantages. However, natural polymers have some drawbacks, which can be addressed through the chemical modification approach. In this review, we will highlight the recent progress in the development of theranostic nanomedicines based on chemically modified natural polymers as well as research prospects for the future.

Naturally occurring biological macromolecules-based hydrogels: Potential biomaterials for peripheral nerve regeneration.

Despite the recent advances in the treatment strategies of peripheral nerve system defects, peripheral nerve injury (PNI) is still one of the most important health issues with increasing incidence worldwide. The most commonly used treatment approaches are allografts, xenografts, and autologous, which have some drawbacks, including complications, limited source of the donor tissue, tubular collapse, and scar tissue formation. In this context, regenerative medicine has been introduced as a powerful approach to improve the healing process and obtain acceptable functional recovery in the injury site using living cells, scaffold, and bioactive (macro-) molecules. Amongst them, scaffold as a three-dimensional (3D) support biomaterial, structurally bridged the gap or site of injury in order to provide physical and chemical cues to promote correct reinnervation and functional regeneration. Amongst different scaffolding biomaterials, naturally occurring biological macromolecules (more especially proteins and polysaccharides)-based hydrogels exhibited promising results due to their fascinating physicochemical, as well as physiologically relevant properties. This review highlights the recent progress in the development of natural hydrogels-based neural scaffolds. Furthermore, PNI healing process, current status, and challenges are also shortly discussed.

A novel bio-inspired conductive, biocompatible, and adhesive terpolymer based on polyaniline, polydopamine, and polylactide as scaffolding biomaterial for tissue engineering application.

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.

Electrically conductive nanofibrous scaffold composed of poly(ethylene glycol)-modified polypyrrole and poly(ε-caprolactone) for tissue engineering applications.

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 AB4 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.

Scaffolding polymeric biomaterials: Are naturally occurring biological macromolecules more appropriate for tissue engineering?

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.

A starch-based stimuli-responsive magnetite nanohydrogel as de novo drug delivery system.

A novel starch-based stimuli-responsive magnetite nanohydrogel (MNHG), namely Fe3O4-g-[poly(N-isopropylacrylamide-co-maleic anhydride)]@strach; Fe3O4-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 Fe3O4-g-(PNIPAAm-co-PMA) nanocomposite was crosslinked through the reaction between the anhydride group of MA and hydroxyl groups of starch to afford a Fe3O4-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.

Chitosan-grafted-poly(methacrylic acid)/graphene oxide nanocomposite as a pH-responsive de novo cancer chemotherapy nanosystem.

The aim of this study was the design and development of a novel de novo drug delivery system for cancer chemotherapy. For this purpose, chitosan (CS) functionalized using phthalic anhydride followed by 4-cyano, 4-[(phenylcarbothioyl) sulfanyl] pentanoic acid as a chain transfer agent (CTA) to afford CS-CTA macroinitiator. The synthesized CS-CTA macroinitiator was then copolymerized with methacrylic acid (MAA) monomer using reversible addition-fragmentation chain transfer (RAFT) polymerization technique to produce chitosan-graft-poly(methacrylic acid) (CS-g-PMAA) graft copolymer. Afterward, graphene oxide (GO) nanosheets were incorporated into the synthesized copolymer through the physical interactions. The CS-g-PMAA/GO nanocomposite was loaded with doxorubicin hydrochloride (DOX) as a universal anticancer drug. The biocompatibility, DOX-loading capacity, and pH dependent drug release behavior of the developed nanocomposite were also investigated. As the experimental results, as well as superior biological and physicochemical features of CS and GO, we envision that the developed CS-g-PMAA/GO nanocomposite may be applied as de novo drug delivery nanosystem for cancer chemotherapy.

A novel gold-based stimuli-responsive theranostic nanomedicine for chemo-photothermal therapy of solid tumors.

The chemo-photothermal therapy performance of a novel theranostic nanoparticles that fabricated through the conjugation of HS-poly(ε-caprolactone)-block-poly(N-isopropylacrylamide)-block-poly(acrylic acid) (HS-PCL-b-PNIPAAm-b-PAA) and gold nanoparticles (GNPs) was extensively investigated. The GNPs@polymer conjugate theranostic NPs was loaded with doxorubicin hydrochloride (DOX) as an anticancer drug through electrostatic interactions to afford GNPs@polymer-DOX theranostic nanomedicine. Temperature and pH-triggered in vitro drug release behavior of the developed theranostic nanomedicine were also examined. The biocompatibility of the synthesized GNPs@polymer theranostic NPs was confirmed through the assessing survival rate of breast cancer cell line (MCF7) using MTT assay. In vitro cytotoxic effects of the GNPs@polymer-DOX theranostic nanomedicine was also evaluated against MCF7 cells in both with or without laser irradiation (532 nm, 145 mJ per pulse, 5 min) conditions, and the results obtained were compared with free DOX as the reference. As the results, the developed GNPs@polymer-DOX can be considered as theranostic nanomedicine for chemo-photothermal therapy of solid tumors.

PEGylated graphene oxide/Fe3O4 nanocomposite: Synthesis, characterization, and evaluation of its performance as de novo drug delivery nanosystem.

This paper describes the development of mitoxantrone-loaded PEGylated graphene oxide/magnetite nanoparticles (PEG-GO/Fe3O4-MTX), and investigation of its preliminary drug delivery performance. For this, the GO was synthesized through oxidizing graphite powder, and subsequently carboxylated using a substitution nucleophilic reaction. The carboxylated GO (GO-COOH) was then conjugated with amine end-caped PEG chains by Steglich esterification. Afterward, GO-PEG/Fe3O4 nanocomposite was synthesized through the anchoring of Fe3O4 nanoparticles onto the surface of GO-PEG during the sonication. The biocompatibility and MTX-loading capacity of the synthesized GO-PEG/Fe3O4 nanocomposite were evaluated. The pH dependent drug release behavior and cytotoxicity effect of the MTX-loaded GO-PEG/Fe3O4 nanocomposite were also studied. According to biocompatibility, pH dependent drug release behavior as well as superior physicochemical and biological characteristics of graphene and magnetite nanoparticles, it is expected that the GO-PEG/Fe3O4 nanocomposite may be applied as de novo drug delivery system (DDS) for cancer therapy using both chemo- and photothermal therapy approaches.

A novel starch-based stimuli-responsive nanosystem for theranostic applications.

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 (Fe3O4 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/Fe3O4 MNHG may be find theranostic applications, in part due to its smart physicochemical properties.

Novel dual stimuli-responsive ABC triblock copolymer: RAFT synthesis, "schizophrenic" micellization, and its performance as an anticancer drug delivery nanosystem.

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 (1H 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 1H 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.

Grafting of poly[(methyl methacrylate)-block-styrene] onto cellulose via nitroxide-mediated polymerization, and its polymer/clay nanocomposite.

For the first time, nitroxide-mediated polymerization (NMP) was used for synthesis of graft and block copolymers using cellulose (Cell) as a backbone, and polystyrene (PSt) and poly(methyl metacrylate) (PMMA) as the branches. For this purpose, Cell was acetylated by 2-bromoisobutyryl bromide (BrBiB), and then the bromine group was converted to 4-oxy-2,2,6,6-tetramethylpiperidin-1-oxyl group by a substitution nucleophilic reaction to afford a macroinitiator (Cell-TEMPOL). The macroinitiator obtained was subsequently used in controlled graft and block copolymerizations of St and MMA monomers to yield Cell-g-PSt and Cell-g-(PMMA-b-PSt). The chemical structures of all samples as representatives were characterized by FTIR and (1)H NMR spectroscopies. In addition, Cell-g-(PMMA-b-PSt)/organophilic montmorillonite nanocomposite was prepared through a solution intercalation method. TEM was used to evaluate the morphological behavior of the polymer-clay system. It was demonstrated that the addition of small percent of organophilic montmorillonite (O-MMT; 3wt.%) was enough to improve the thermal stability of the nanocomposite.

Development of novel electrically conductive scaffold based on hyperbranched polyester and polythiophene for tissue engineering applications.

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.