Showing papers in "Journal of Nanoscience and Nanotechnology in 2016"

Nanotechnology Applied to Bio-Encapsulation of Pesticides.

Abstract: In recent years, many efforts have been made towards the application of nanotechnology in sustainable food production. In this context, the bio-encapsulation process has taken prominence in particular as an ecofriendly method for pest control while reducing the pesticide load in the environment considerably. By taking into consideration, here we are presenting an overview regarding the prospects for the development of nanoencapsulated pesticides in sustainable agriculture and highlight some challenges to be addressed in order to develop efficient nano-carrier systems that may arise as an alternative for conventional pesticide application. However, much research has to be done in this area in order to develop safe and promising pesticide delivery systems for increasing global food production by enhancing the selectivity, specificity and longevity of the encapsulated pesticides while reducing the negative environmental impacts to ecosystem and human beings.

Synergistic Nanomedicine: Passive, Active, and Ultrasound-Triggered Drug Delivery in Cancer Treatment.

Abstract: Nanocarriers are heavily researched as drug delivery vehicles capable of sequestering antineoplastic agents and then releasing their contents at the desired location. The feasibility of using such carriers stems from their ability to produce a multimodel delivery system whereby passive, ligand and triggered targeting can be applied in the fight against cancer. Passive targeting capitalizes on the leaky nature of tumor tissue which allows for the extravasation of particles with a size smaller than 0.5 µm into the tumors. Ligand targeting utilizes the concept of receptor-mediated endocytosis and involves the conjugation of ligands onto the surface of nanoparticles, while triggered targeting involves the use of external and internal stimuli to release the carriers contents upon reaching the diseased location. In this review, micelles and liposomes have been considered due to the promising results they have shown in vivo and in vitro and their potential for advancements into clinical trials. Thus, this review focuses on the most recent advancements in the field of micellar and liposomal drug delivery and considers the synergistic effect of passive- and ligand-targeting strategies, and the use of ultrasound in triggering drug release at the tumor site.

The Role of Mn(2+)-Doping on Structural, Morphological, Optical, Magnetic and Catalytic Properties of Spinel ZnFe2O4 Nanoparticles.

Abstract: Spinel Mn(x)Zn(1-x)Fe2O4 (0.0 ≤ x ≤ 1.0) nanoparticles (NPs) were successfully synthesized by a facile one-pot microwave combustion method using urea as the fuel. The formation of single phase cubic spinel structure was confirmed by powder X-ray diffraction (XRD), Rietveld analysis and Fourier transform infrared (FT-IR) spectroscopy and the calculated average crystallite size is in the range of 37.57 nm to 25.43 nm. The high resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscopy (HR-TEM) results indicated that the as-prepared spinel Mn(x)Zn(1-x)Fe2O4 NPs showed high crystallinity and uniform size distribution with particles-like morphologies. The energy dispersive X-ray (EDX) analysis was confirmed the elemental composition and purity of the samples. The estimated band gap energy from UV-Visible diffuse reflectance spectroscopy (UV-Vis. DRS) is about 1.88 eV to 2.35 eV. The broad visible emission band is observed in the entire photoluminescence (PL) spectroscopy for all compositions. The variation of magnetization (M(s)) value of the samples was studied by vibrating sample magnetometer (VSM) and the lower compositions (x = 0.0, 0.2 and 0.4) show a superparamagnetism and the higher composition (x = 0.6, 0.8 and 1.0) show a ferromagnetic behavior with hysteresis and that the M(s) values increased with increasing Mn2+ content to reach a maximum value of 60.99 emu/g for MnFe2O4. All composition of spinel Mn(x)Zn(1-x)Fe2O4 NPs were successfully tested as catalyst for the oxidation of benzyl alcohol into benzaldehyde, which has resulted 83.29 and 96.51% conversion efficiency of ZnFe2O4 and Mn0.6Zn0.4Fe2O4 respectively.

Advanced Gold Nanomaterials for Photothermal Therapy of Cancer

Abstract: Photothermal therapy represents a non-invasive therapeutic tool to eradicate cancer tumor with minimum toxic effects. In this ablative therapy, accurate delivery of efficient photothermal conversion agents followed by laser irradiation results in tumor ablation with lower toxicity compared to other cancer therapies. Gold nanomaterials are efficient to passively target and deliver photothermal agents to the cancer tumor. Through surface plasma resonance, gold nanomaterials including nanorods, nanostars, nanoflowers, nanocages and nanoshells exhibited strong NIR absorption and are widely utilized during photothermal ablative therapy of cancer. Currently, researchers have devoted their attention to minimize toxicity of photothermal agents using modified probe design. By developing this noninvasive cancer therapy, expectations to minimize toxicity of cancer treatment may become reality sooner.

Monodisperse Pt Nanoparticles Assembled on Reduced Graphene Oxide: Highly Efficient and Reusable Catalyst for Methanol Oxidation and Dehydrocoupling of Dimethylamine-Borane (DMAB).

Abstract: Herein, monodisperse platinum (0) nanocatalyst assembled on reduced graphene oxide (Pt(0)@RGO) was easily and reproducibly prepared by the double solvent reduction method at room temperature. Pt(0)@RGO was characterized by X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS) and transmission electron microscopy (TEM) measurements that verify the formation of monodisperse Pt (0) nanoparticles on RGO. The catalytic and electrocatalytic performances of Pt(0) @ RGO in terms of activity, isolability and reusability were investigated for both methanol oxidation and the dehydrocoupling of dimethylamine-borane (DMAB) in which Pt(0)@RGO was found to be highly active and reusable heterogeneous catalyst even at room temperature. The prepared nanoparticles can also electrocatalyze methanol oxidation with very high electrochemical activities (5.64 A/cm2 at 0.58 V for methanol). The activation energy (Ea), activation enthalpy (ΔH#), and activation entropy (ΔS#) for DMAB dehydrogenation were calculated to be 59.33 kJ mol(-1), 56.79 kJ mol(-1) and -151.68 J mol(-1) K(-1), respectively. The exceptional stability of new Pt(0) @ RGO nanoparticles towards agglomeration, leaching and CO poisoning allow these particles to be recycled and reused in the catalysis of DMAB dehydrogenation and methanol oxidation. After four subsequent reaction and recovery cycles, Pt(0) @ RGO retained ≥ 75% activity towards the complete dehydrogenation of DMAB.

Graphene Oxide as Highly Effective and Readily Recyclable Catalyst Using for the One-Pot Synthesis of 1,8-Dioxoacridine Derivatives.

Abstract: Graphene oxide as a highly stable, reusable, isolable, and efficient catalyst has been used for the first time for the synthesis of acridinedione derivatives from dimedone, aromatic aldehydes and various amines with great catalytic performance. One pot synthesis of acridinedione compounds were performed using highly efficient graphene oxide.

Synthesis and Characterization of Nearly Monodisperse Pt Nanoparticles for C1 to C3 Alcohol Oxidation and Dehydrogenation of Dimethylamine-borane (DMAB).

Abstract: Highly efficient nearly monodisperse Pt NPs catalyze C1 to C3 alcohol oxidation with very high electrochemical activities and provides one of the highest catalytic activities (TOF = 21.50 h(-1)) in the dehydrogenation of DMAB at room temperature. The exceptional stability towards agglomeration, leaching and CO poisoning for the prepared catalyst allow these particles to be recycled and reused in the catalysis of both DMAB dehydrogenation and C1 to C3 alcohol oxidation. After four subsequent reaction and recovery cycles, catalyst retained ≥ 80% activity towards the complete dehydrogenation of DMAB. The prepared catalyst structures were determined by the X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM) respectively.

Sesamum indicum Plant Extracted Microwave Combustion Synthesis and Opto-Magnetic Properties of Spinel MnxCo₁₋xAl₂O₄Nano-Catalysts.

Abstract: Spine Mn(x)Co₁₋xAl₂O₄ (x = 0, 0.3 and 0.5) nanoparticles were synthesized using Sesamum indicum (S. indicum) plant extracted microwave-assisted combustion method. S. indicum plant extract simplifies the process, provides an alternative process for a simple, economical and environment friendly synthesis. The absence of surfactant/catalysts has led to a simple, cheap and fast method of synthesis of spinel nanoparticles. The as-synthesized spinel nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, high resolution scanning electron microscopy (HR-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), Brunauer Emmett Teller (BET) surface area analysis, UV-Visible diffuse reflectance spectroscopy (DRS), Photoluminescence (PL) spectroscopy, and vibrating sample magnetometer. The formation of spinel nanoparticles was confirmed by HR-SEM and HR-TEM and their possible formation mechanisms were also proposed. Powder XRD, FT-IR, SAED and EDX results confirmed the formation of pure and single cubic phase CoAl₂O₄ with well-defined crystalline. The optical property was determined by DRS and PL spectra. VSM measurements revealed that pure and Mn-doped CoAl₂O₄ samples have weak ferromagnetic behavior and the magnetization values increases with increasing the concentration of Mn²⁺ ions in the CoAl₂O₄ lattice. The sample Mn₀.₅Co₀.₅Al₂O₄ possessed higher surface area and smaller crystallite size than other samples, which led to enhance the performance toward the selective oxidation of benzyl alcohol into benzaldehyde.

Synthesis, Characterizations of Superparamagnetic Fe3O4-Ag Hybrid Nanoparticles and Their Application for Highly Effective Bacteria Inactivation.

Abstract: In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic activity of Ag-NPs with good dispersion and aggregation stability due to the iron oxide magnetic carrier, and (iii) large direct physical contacts between the bacterial cell membrane and the hybrid nanoparticles. The superparamagnetic hybrid nanoparticles of iron oxide magnetic nanoparticles decorated with silver nanoparticles can be a potential candidate to effectively treat infectious MRSA pathogen with recyclable capability, targeted bactericidal delivery and minimum release into environment.

Synergy Between Polyvinylpyrrolidone-Coated Silver Nanoparticles and Azole Antifungal Against Drug-Resistant Candida albicans.

Abstract: In the clinical practice, resistance of Candida albicans to antifungal agents has frequently emerged. Silver-nanoparticles (Ag-NPs) have been demonstrated to have the antifungal property. We investigated the potential for synergy between polyvinylpyrrolidone (PVP)-coated Ag-NPs and azole antifungal, such as fluconazole or voriconazole, against drug-resistant C. albicans strain CA10. When antifungal agent was examined alone, fluconazole and voriconazole did not kill drug-resistant C. albicans, and PVP-coated Ag-NPs had only the moderate killing ability. In contrast, the combinational treatment of PVP-coated Ag-NPs with fluconazole or voriconazole was effective in being against the drug-resistant C. albicans. After the combinational treatment, we detected the disruption of cell membrane integrity, the tendency of PVP-coated Ag-NPs to adhere to cell membrane, and the inhibition of budding process. Moreover, after the combinational treatment, the defects in ergosterol signaling and efflux pump functions were detected. Our results suggest that the combinational use of engineered nanomaterials (ENMs), such as PVP-coated Ag-NPs, with the conventional antifungal may be a viable strategy to combat drug-resistant fungal infection.

Nanomaterial Induced Immune Responses and Cytotoxicity.

Abstract: Nanomaterials are utilized in a wide array of end user products such as pharmaceuticals, electronics, clothes and cosmetic products. Due to its size (< 100 nm), nanoparticles have the propensity to enter through the airway and skin, making its path perilous with the potential to cause damages of varying severity. Once within the body, these particles have unconstrained access to different tissues and organs including the brain, liver, and kidney. As a result, nanomaterials may cause the perturbation of the immune system eliciting an inflammatory response and cytotoxicity. This potential role is dependent on many factors such as the characteristics of the nanomaterials, presence or absence of diseases, and genetic predisposition. Cobalt and nickel nanoparticles, for example, were shown to have inflammogenic properties, while silver nanoparticles were shown to reduce allergic inflammation. Just as asbestos fibers, carbon nanotubes were shown to cause lungs damage. Some nanomaterials were shown, based on animal studies, to result in cell damage, leading to the formation of pre-cancerous lesions. This review highlights the impact of nanomaterials on immune system and its effect on human health with toxicity consideration. It recommends the development of suitable animal models to study the toxicity and bio-clearance of nanomaterials and propose safety guidelines.

Using Gold Nanoparticles as Delivery Vehicles for Targeted Delivery of Chemotherapy Drug Fludarabine Phosphate to Treat Hematological Cancers.

Abstract: Nanotechnology is an emerging paradigm for creating functional nanoscale materials for various biomedical applications. In this study, a new nanotechnology-based drug delivery method was developed using gold nanoparticles (GNPs) as a delivery vehicle to reduce adverse drug side effects. Fludarabine Phosphate is a commercial chemotherapy drug used in cancer treatment, and has ability to kill various cancer cells. KG-1 cell, a type of acute cancer leukemia cell, was selected as a proof-of-concept target in this study. Due to the small size of GNPs, they can help Fludarabine Phosphate enter cancer cells more efficiently and better interfere with DNA synthesis in the cancer cells. To enhance targeting ability, folic acid molecules were also covalently linked to GNPs, resulting in GNP-Fludarabine-folic acid (GNP-F/f). Compared to treatments with GNP-F or drugs on its own (Fludarabine Phosphate), the GNP-F/f achieves much improved cell-killing effects. The UV-Vis spectra results also revealed that the drugs had successfully bonded covalently to the GNPs. The higher cell-killing efficiency of GNP-F/f compared with GNP-Fludarabine (GNP-F) or drugs on their own further validates the effectiveness of both the vectors (GNPs) and folic acid in enhancing the drug delivery to the cancer cells. The MTT viability tests showed that the GNPs had no cytotoxicity.

CO2 Adsorption Over Metal-Organic Frameworks: A Mini Review.

Abstract: Metal-organic frameworks (MOFs) are a class of porous materials that are comprised of metal ion-containing nodes linked by multi-dentate organic ligand bridges principally through coordination bonding. Over the last few decades, MOFs have been studied widely as CO2 adsorbents. CO2 adsorption in MOFs can be enhanced by tuning their physicochemical properties. This short review discusses CO2 adsorption over MOFs with particular focus on the contributory effects of (1) inherent textural properties, (2) coordinatively unsaturated open metal sites, (3) surface functionalization, (4) structural interpenetration (catenation), and (5) ion-exchange.

In Vitro Uptake of Silver Nanoparticles and Their Toxicity in Human Mesenchymal Stem Cells Derived from Bone Marrow.

Abstract: During the last decade, the usage of silver nanoparticles in biomedical fields has increased rapidly, mainly due to their excellent antibacterial effects. They are used in many medical products such as wound dressings, catheters, bone cement and artificial cardiac valves. In tissue engineering, silver nanoparticles are often loaded as a filler for fabrication of nanocomposite scaffolds which subsequently are seeded with human mesenchymal stem cells. Thus, possible adverse effects of silver nanoparticles on human stem cells should be investigated carefully to ensure a safe usage. In this study, silver nanoparticles with a mean diameter of ~30 nm were prepared and their toxicity in human mesenchymal stem cells was investigated. Transmission electron microscopic images reveal the uptake and localization of the silver nanoparticles in the cytoplasm. Upon internalization of Ag NPs inside the cells, an increase in the release of lactate dehydrogenase and the production of reactive oxygen species was quantified. Furthermore, they caused a reduction in both cell viability and mitochondrial membrane potential in a dose-dependent manner. Annexin V-FITC/PI staining implied that silver nanoparticles did not only induce apoptosis but also cause necrosis. Based on cell cycle analysis, G2/M arrest was detected in cells treated with silver nanoparticles, implicating DNA damage. The high level of reactive oxygen species induced by nanoparticles is considered to be the main cause of their toxicity.

Enhanced Cytotoxicity of Biomolecules Loaded Metallic Silver Nanoparticles Against Human Liver (HepG2) and Prostate (PC3) Cancer Cell Lines.

Abstract: Green nanoparticle synthesis was achieved using environmentally acceptable plant extracts reducing and capping agents. The present study was based on assessments to the anticancer activities to determine the effect of synthesized silver nanoparticles (AgNPs) from three medicinal plants on human liver (HepG2) and prostate (PC3) cancer cell lines. The synthesis of AgNPs using Plumbago zeylanica (Pz), Semecarpus anacardium (Sa) and Terminalia arjuna (Ta) plant extracts in the reaction mixture was monitored by UV-visible spectroscopy. FTIR results clearly illustrated that the plant extracts containing prominent peaks of functional groups and biomolecules viz., tannins, phenols, flavonoids and triterpenoids those act as capping agents and involved in the stabilization of the synthesised silver nanoparticles. Synthesized AgNPs were spherical and cuboid in shape which is determined by SEM. Average size of the AgNPs were between 80-98, 60-95 and 34-70 nm for PzAgNPs, SaAgNPs and TaAgNPs, respectively. Further, the synthesized AgNPs were characterized by XRD, EDX, DLS and Zeta potential analysis. Moreover, the synthesized AgNPs exhibited a dose-dependent cytotoxicity against human liver and prostate cancer cell lines. The inhibitory concentration (IC50) values of HepG2, PC3 and Vero cells were found to be 70.97, 58.61, 96.41; 10.04, 42.77, 83.86; and 28.42, 41.78, 69.48 μg/ml for PzAgNPs, SaAgNPs and TaAgNPs at 48 h incubation. An induction of apoptosis was confirmed by DNA fragmentation, Hoechst, Rhodamine and AO/EtBr staining. The present results strongly suggested that the AgNPs synthesized using P. zeylanica, S. anacardium and T. arjuna extracts showed potential anticancer activity of HepG2 and PC3 cell lines.

Bovine Serum Albumin Nanoparticles Containing Quercetin: Characterization and Antioxidant Activity.

Abstract: Quercetin is a flavonoid reported as anti-allergic, anti-inflammatory, antiplatelet, anti-microbial, antioxidant, antineurodegenerative and antitumoral. However, due to its low water solubility, its efficacy is restricted. Nanotechnology can be an importante tool to improve the quercetin properties and increase its bioavailability. In this study, bovine serum albumin (BSA) nanoparticles containing quercetin were developed by desolvation technique, characterized the mean particle size, polydispersity, zeta potential, encapsulation efficiency, physical state of drug in nanoparticles and drug release profile as well as their antioxidant activity was evaluated. The influence of glutaraldehyde percentage in nanoparticles properties was evaluated and did not influence the nanoparticles parameters. Nanoparticles presented a mean size around 130 nm and encapsulation efficiency around 85%. Results from X-ray diffractometry showed that the crystal of the drug was converted to an amorphous state in polymeric matrix. Quercetin release profile demonstrated a biphasic pattern and after 96 h approximately 18% of drug was released. Kinetic models demonstrated that the quercetin release followed a second-order model and the release was governed by Fickian diffusion. After 96 h, quercetin-loaded nanoparticles were more effective than free quercetin for scanvenger of radical ABTS + and hypochlorous acid. BSA nanoparticles represents potential carriers for improve quercetin properties.

Development and Evaluation of Lipid Nanoparticles for Drug Delivery: Study of Toxicity In, Vitro and In Vivo.

Abstract: Lipid nanoparticles have received considerable attention in the field of drug delivery, due their ability to incorporate lipophilic drugs and to allow controlled drug release. Solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nanoemulsion (NE) are three different lipid nanostructured systems presenting intrinsically physical properties, which have been widely studied in recent years. Despite the extensive applicability of lipid nanoparticles, the toxicity of these systems has not been sufficiently investigated thus far. It is generally believed that lipids are biocompatible. However, it is known that materials structured in nanoscale might have their intrinsic physicochemical properties modified. Thus, the aim of this study was to evaluate the cytotoxicity of these three nanoparticle systems. To this end, in vitro and in vivo toxicity studies were carried out. Our results indicate that nanoparticles containing the solid lipid GMS (SLN and NLC) induced an important cytotoxicity in vitro, but showed minimal toxicity in vivo--evidenced by the body weight analysis. The NE did not induce in vitro toxicity and did not induce body weight alteration. On the contrary, the SLN and NLC possibly induce an inflammatory process in vivo. All nanoparticle systems induced lipid peroxidation in the animals' livers, but only SLN and NLC induced a decrease of antioxidant defences indicating that the main mechanism of toxicity is the induction of oxidative stress in liver. The higher toxicity induced by SLN and NLC indicates that the solid lipid GMS could be the responsible for this effect. Nevertheless, this study provides important insights for toxicological studies of different lipid nanoparticles systems.

Application of Molecular Imprinted Magnetic Fe3O4@SiO2 Nanoparticles for Selective Immobilization of Cellulase.

Abstract: Magnetic Fe3O4@SiO2 nanoparticles were prepared with molecular imprinting method using cellulase as the template. And the surface of the nanoparticles was chemically modified with arginine. The prepared nanoparticles were used as support for specific immobilization of cellulase. SDS-PAGE results indicated that the adsorption of cellulase onto the modified imprinted nanoparticles was selective. The immobilization yield and efficiency were obtained more than 70% after the optimization. Characterization of the immobilized cellulase revealed that the immobilization didn't change the optimal pH and temperature. The half-life of the immobilized cellulase was 2-fold higher than that of the free enzyme at 50 degrees C. After 7 cycles reusing, the immobilized enzyme still retained 77% of the original activity. These results suggest that the prepared imprinted nanoparticles have the potential industrial applications for the purification or immobilization of enzymes.

Cationic Polymeric Nanocapsules as a Strategy to Target Dexamethasone to Viable Epidermis: Skin Penetration and Permeation Studies.

Abstract: The present work aimed to evaluate the behavior of dexamethasone-loaded cationic polymericnanocapsules in hydrogels, regarding their in vitro drug release and skin drug retention and per- meation. Cationic polymeric nanocapsules prepared with Eudragit RS 100 as the polymeric wall had mean particle size of 139 +/- 3.6 nm, positive zeta potential (+11.38 +/- 1.7 mV), and high encapsulation efficiency (81 +/- 2%). After preparation, they were formulated as hydrogels, which showed non-Newtonian, plastic behavior, and acidic pH. Photon correlation spectroscopy analysis of these hydrogels demonstrated the presence of particles with mean particle size close to that of the original colloidal suspensions. The presence of dexamethasone-loaded nanocapsules in hydrogels promoted controlled drug release and an increase in the amount of drug delivered into viable epidermis, the main target tissue to topical glucocorticoid action. Moreover, the formulation did not increase the risk of drug penetration to dermis and permeation to the receptor compartment.

Neuroprotective Potential of Superparamagnetic Iron Oxide Nanoparticles Along with Exposure to Electromagnetic Field in 6-OHDA Rat Model of Parkinson's Disease.

Abstract: Parkinson's disease (PD) is a progressive neurodegenerative disorder affecting mainly the dopaminergic neurons of the substantia nigra leading to various motor and non-motor deficits. We explored the neuroprotective potential of superparamagnetic iron oxide nanoparticles (IONPs) along with exposure to EMF in 6-OHDA rat model of PD. IONPs were implanted at the site of lesion and 24 h thereafter the rats were exposed to magnetic fields 2 h/day for one week. Bilateral lesions of the striatum were made with 6-OHDA. The rats in all the intervention groups improved progressively over the days and by post-surgery day 4 they were active and bright. We observed a significant beneficial effect of the IONPs implantation and MF exposure on feeding behavior, gait and postural stability. There was a significant enhancement of mitochondrial function and attenuation of lesion volume in all the intervention groups as compared to PD. The results demonstrate neuroprotective effect of iron oxide nanoparticle implantation and magnetic field exposure in an in vivo 6-OHDA rat model of PD.

Tubular Tissues and Organs of Human Body--Challenges in Regenerative Medicine.

Abstract: Tissue engineering of tubular organs such as the blood vessel, trachea gastrointestinal tract, urinary tract are of the great interest due to the high amount of surgeries performed annually on those organs. Development in tissue engineering in recent years and promising results, showed need to investigate more complex constructs that need to be designed in special manner. Stent technology remain the most widely used procedure to restore functions of tubular tissues after cancer treatment, or after organ removal due to traumatic accidents. Tubular structures like blood vessels, intestines, and trachea have to work in specific environment at the boundary of the liquids, solids or air and surrounding tissues and ensure suitable separation between them. This brings additional challenges in tissue engineering science in order to construct complete organs by using combinations of various cells along with the support material systems. Here we give a comprehensive review of the tubular structures of the human body, in perspective of the current methods of treatment and progress in regenerative medicine that aims to develop fully functioning organs of tubular shape. Extensive analysis of the available literature has been done focusing on materials and methods of creations of such organs. This work describes the attempts to incorporate growth factors and drugs within the scaffolds to ensure localized drug release and enhance vascularization of the organ by attracting blood vessels to the site of implantation.

Paclitaxel-Loaded TPGS-b-PCL Nanoparticles: In Vitro Cytotoxicity and Cellular Uptake in MCF-7 and MDA-MB-231 Cells versus mPEG-b-PCL Nanoparticles and Abraxane®.

Abstract: Nanomedicines have become an attractive platform for the development of novel drug delivery systems in cancer chemotherapy. Polymeric nanoparticles (NPs) represent one of the best well-investigated nanosized carriers for delivery of antineoplastic compounds. The "Pegylation strategy" of drug delivery systems has been used in order to improve carrier biodistribution, however, some nanosized systems with PEG on their surface have exhibited poorly-cellular drug internalization. In this context, the purpose of the present study was to compare in vitro performance of two paclitaxel (PTX)-loaded NPs systems based on two biocompatible copolymers of alpha tocopheryl polyethylene glycol 1000 succinate-block-poly(e-caprolactone) (TPGS-b-PCL) and methoxyPEG- block-poly(e-caprolactone) (mPEG-b-PCL) in terms of citotoxicity and PTX cellular uptake. Fur- thermore, TPGS-b-PCL NPs were also copared with the commercially available PTX nano-sized formulation Abraxane®. Both TPGS-b-PCL and mPEG-b-PCL derivates were synthesized by ring opening polymerization of e-caprolactone employing microwaved radiation. NPs were obtained by a solvent evaporation technique where the PTX content was determined by reverse-phase HPLC. The resulting NPs had an average size between 200 and 300 nm with a narrow size distribution. Also both NPs systems showed a spherical shape. The in vitro PTX release profile from the NPs was characterized employing the dialysis membrane method where all drug-loaded formulations showed a sustained and slow release of PTX. Finally, in vitro assays demonstrated that PTX-loaded TPGS- b-PCL exhibited a significant higher antitumor activity than PTX-loaded mPEG-b-PCL NPs and Abraxane® against an estrogen-dependent (MCF-7) and an estrogen independent (MDA-MB-231) breast cancer cells lines. Furthermore TPGS-b-PCL NPs showed a significant increase on PTX cellular uptake, for both breast cell lines, in comparison with mPEG-b-PCL NPs and Abraxane®. Overall findings confirmed that NPs based on TPGS-b-PCL as biomaterial demonstrated a better in vitro performance than NPs with PEG, representing an attractive alternative for the development of novel nanosized carriers for anticancer therapy.