Synthesis of Poly(L-lactide)-poly(ε-caprolactone)-poly(ethylene glycol) Terpolymer Grafted onto Partially Oxidized Carbon Nanotube Nanocomposites for Drug Delivery.

Nanocomposites prepared with a terpolymer of poly(L-lactide) (PLLA)-poly(ε-caprolactone) (PCL)-poly(ethylene glycol) (PEG) and partially oxidized carbon nanotubes (CNTspo) were synthesized and characterized to evaluate their ability to act as an effective nanocarrier of the anticancer drug methotrexate. The homopolymers of PLLA and PCL were synthesized through ring-opening polymerization (ROP) and characterized through gel permeation chromatography (GPC). The PLLA-PCL-PEG terpolymers were synthesized through a four-step chemical route using oxalyl chloride as a linker agent and analyzed with 1H-NMR, 13C-NMR, and FTIR spectroscopies. Additionally, the nanocomposites were characterized through FTIR, and X-ray photoelectron spectroscopy (XPS), as well as the differential scanning calorimetry (DSC) technique. XPS analysis revealed that PLLA-PCL-PEG terpolymer chains are grafted onto CNTspo. Moreover, evaluations through FTIR and DSC strongly suggest that the PCL-rich domains are preferentially oriented toward CNTspo. The release tests exhibited a "burst effect" profile, which was more evident in the terpolymers than in the nanocomposites. Five models were used to assess methotrexate's in vitro release. For the nanocomposites, the best fit to the experimental data was obtained using the first-order model, whereas the results obtained from the Korsmeyer-Peppas model indicated that Fickian diffusion drives methotrexate's release.

Interplay between mucus mobility and alveolar macrophage targeting of surface-modified liposomes.

Alveolar macrophages play a crucial role in the initiation and resolution of the immune response in the lungs. Pro-inflammatory M1 alveolar macrophages are an interesting target for treating inflammatory and infectious pulmonary diseases. One commune targeting strategy is to use nanoparticles conjugated with hyaluronic acid, which interact with CD44 overexpressed on the membrane of those cells. Unfortunately, this coating strategy may be countered by the presence on the surface of the nanoparticles of a poly(ethylene glycol) corona employed to improve nanoparticles' diffusion in the lung mucus. This study aims to measure this phenomenon by comparing the behavior in a murine lung inflammation model of three liposomal platforms designed to represent different poly(ethylene glycol) and hyaluronic acid densities (Liposome-PEG, Liposome-PEG-HA and Liposome-HA). In this work, the liposomes were obtained by a one-step ethanol injection method. Their interaction with mucin and targeting ability toward pro-inflammatory macrophages were then investigated in vitro and in vivo in a LPS model of lung inflammation. In vitro, poly(ethylene glycol) free HA-liposomes display a superior targeting efficiency toward M1 macrophages, while the addition of poly(ethylene glycol) induces better mucus mobility. Interestingly in vivo studies revealed that the three liposomes showed distinct cell specificity with alveolar macrophages demonstrating an avidity for poly(ethylene glycol) free HA-liposomes, while neutrophils favored PEGylated liposomes exempt of HA. Those results could be explained by the presence of two forces exercising a balance between mucus penetration and receptor targeting. This study corroborates the importance of considering the site of action and the targeted cells when designing nanoparticles to treat lung diseases.

Chitosan as a matrix of nanocomposites: A review on nanostructures, processes, properties, and applications.

Chitosan is a biopolymer that is natural, biodegradable, and relatively low price. Chitosan has been attracting interest as a matrix of nanocomposites due to new properties for various applications. This study presents a comprehensive overview of common and recent advances using chitosan as a nanocomposite matrix. The focus is to present alternative processes to produce embedded or coated nanoparticles, and the shaping techniques that have been employed (3D printing, electrospinning), as well as the nanocomposites emerging applications in medicine, tissue engineering, wastewater treatment, corrosion inhibition, among others. There are several reviews about single chitosan material and derivatives for diverse applications. However, there is not a study that focuses on chitosan as a nanocomposite matrix, explaining the possibility of nanomaterial additions, the interaction of the attached species, and the applications possibility following the techniques to combine chitosan with nanostructures. Finally, future directions are presented for expanding the applications of chitosan nanocomposites.

Docetaxel in chitosan-based nanocapsules conjugated with an anti-Tn antigen mouse/human chimeric antibody as a promising targeting strategy of lung tumors.

The aim of this work was to evaluate the physicochemical and biological properties of docetaxel (DCX) loaded chitosan nanocapsules (CS Nc) functionalized with the monoclonal antibody Chi-Tn (CS-PEG-ChiTn mAb Nc) as a potential improvement treatment for cancer therapy. The Tn antigen is highly specific for carcinomas, and this is the first time that such structure is targeted for drug delivery. The nanocapsules (Ncs), formed as a polymeric shell around an oily core, allowed a 99.9% encapsulation efficiency of DCX with a monodispersity particle size in the range of 200 nm and a high positive surface charge that provide substantial stability to the nanosystems. Release profile of DCX from Ncs showed a sustained and pH dependent behavior with a faster release at acidic pH, which could be favorable in the intracellular drug delivery. We have designed PEGylated CS Nc modified with a monoclonal antibody which recognize Tn antigen, one of the most specific tumor associated antigen. A biotin-avidin approach achieved the successful attachment of the antibody to the nanocapsules. Uptake studies and viability assay conducted in A549 human lung cancer cell line in vitro demonstrate that ChiTn mAb enhance nanoparticles internalization and cell viability reduction. Consequently, these ChiTn functionalized nanocapsules are promising carriers for the active targeting of DCX to Tn expressing carcinomas.

Small interfering RNA for cancer treatment: overcoming hurdles in delivery.

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

A carbon paste electrode improved with poly(ethylene glycol) for tannic acid surveillance in beer samples.

Tannic acid is often used as additive in beers and is an important parameter to be evaluated in quality control of beverages. Thus, this paper describes the improvement of a carbon paste electrode through its modification with poly(ethylene glycol) for determination of tannic acid in beers. Microscopic and electrochemical techniques were used to characterize the modified surface. The electrochemical behavior of tannic acid and the optimization of experimental parameters (pH, supporting electrolyte and accumulation step) on the modified surface were performed by cyclic voltammetry. The calibration plot for tannic acid by differential pulse voltammetry was linear in the range of 0.08-2.10 µmol L-1 with limits of detection and quantification of 72.6 and 220 nmol L-1, respectively. Lastly, the carbon paste electrode improved with poly(ethylene glycol) was effectively implemented in the quantification of tannic acid in beer samples. The results were similar to those furnished by the Folin-Ciocalteu method.

Co-Loaded Curcumin and Methotrexate Nanocapsules Enhance Cytotoxicity against Non-Small-Cell Lung Cancer Cells.

Background: As part of the efforts to find natural alternatives for cancer treatment and to overcome the barriers of cellular resistance to chemotherapeutic agents, polymeric nanocapsules containing curcumin and/or methotrexate were prepared by an interfacial deposition of preformed polymer method. Methods: Physicochemical properties, drug release experiments and in vitro cytotoxicity of these nanocapsules were performed against the Calu-3 lung cancer cell line. Results: The colloidal suspensions of nanocapsules showed suitable size (287 to 325 nm), negative charge (-33 to -41 mV) and high encapsulation efficiency (82.4 to 99.4%). Spherical particles at nanoscale dimensions were observed by scanning electron microscopy. X-ray diffraction analysis indicated that nanocapsules exhibited a non-crystalline pattern with a remarkable decrease of crystalline peaks of the raw materials. Fourier-transform infrared spectra demonstrated no chemical bond between the drug(s) and polymers. Drug release experiments evidenced a controlled release pattern with no burst effect for nanocapsules containing curcumin and/or methotrexate. The nanoformulation containing curcumin and methotrexate (NCUR/MTX-2) statistically decreased the cell viability of Calu-3. The fluorescence and morphological analyses presented a predominance of early apoptosis and late apoptosis as the main death mechanisms for Calu-3. Conclusions: Curcumin and methotrexate co-loaded nanocapsules can be further used as a novel therapeutic strategy for treating non-small-cell lung cancer.

Synthesis, characterization, and in vitro evaluation of gamma radiationinduced PEGylated isoniazid

Background: The search for innovative anti-tubercular agents has received increasing attention in tuberculosis chemotherapy because Mycobacterium tuberculosis infection has steadily increased over the years. This underlines the necessity for new methods of preparation for polymer-drug adducts to treat this important infectious disease. The use of poly(ethylene glycol)(PEG) is an alternative producing anti-tubercular derivatives. However, it is not yet known whether PEGylated isonicotinylhydrazide conjugates obtained by direct links with PEG are useful for therapeutic applications. Results: Here, we synthesized a PEGylated isoniazid (PEG-g-INH or PEG­INH) by gamma radiation-induced polymerization, for the first time. The new prodrugs were characterized using Raman and UV/Vis spectrometry. The mechanism of PEGylated INH synthesis was proposed. The in vitro evaluation of a PEGylated isonicotinylhydrazide macromolecular prodrug was also carried out. The results indicated that PEG­INH inhibited the bacterial growth above 95% as compared with INH, which showed a lower value (80%) at a concentration of 0.25 µM. Similar trends are observed for 0.1, 1, and 5 µM. Conclusions: In summary, the research suggests that it is possible to covalently attach the PEG onto INH by the proposed method and to obtain a slow-acting isoniazid derivative with little toxicity in vitro and higher antimycobacterial potency than the neat drug.

PLA/PGA and its co-Polymers in Alveolar Bone Regeneration. A Systematic Review / PLA/PGA y sus Copolímeros en Regeneración Ósea Alveolar. Una Revisión Sistemática

ABSTRACT: The aim of this research was to perform a systematic review to identify the most frequent uses of PLA/ PGA in alveolar bone regeneration and their results. A study was designed to answer the question: What are the most frequent uses of PLA/PLGA and their copolymers in alveolar bone regeneration?. A systematic search was done on MEDLINE, EMBASE and LILACS from April 1993 to December 2017. The search string used on MEDLINE was: (((polylactic acid) OR PLA) OR PLA-based copolymers) OR PLA blends) OR PLA scaffolds)) AND ((("Bone Regeneration"[Mesh]) OR bone regeneration) OR guided bone regeneration). The search was complemented by a manual review of the references from the articles included. Most of the studies selected were weak and, regarding the most frequent uses of PLA/PGA, 13 studies used it as a resorbable membrane, two as an absorbable mesh, one as an absorbable screw and three as filling material. Based on our results, the authors consider that PLA/PGA requires a delicate relation between the mechanical resistance and the degradation process. PLA/PGA does not interrupt bone regeneration; however, the influence in cellular events related to bone regeneration and later osseointegration have not been identified.

RESUMEN: El objetivo de esta revisión fue realizar una revisión sistemática de la literatura para identificar los usos más frecuentes de PLA/PGA en regeneración ósea en área maxilofacial y sus resultados. Se diseñó un estudio para responder a la pregunta: ¿Cuáles son los usos más frecuentes de PLA/PLGA y sus copolímeros en regeneración ósea en el sector maxilofacial?. Los estudios seleccionados fueron en su mayoría débiles y sobre los usos más frecuentes de PLA/PGA, 13 estudios lo utilizaron como membrana reabsorbible, 2 estudios como malla absorbible, un estudio como tornillo absorbible y 3 estudios como material de relleno. En base a nuestros resultados, los autores estiman que PLA/PGA requiere una delicada relación entre la resistencia mecánica que ofrece y la degradación que se produce; PLA/ PGA no interrumpe la regeneración ósea, sin embargo, no se ha identificado la potencialidad o influencia que presenta en los eventos celulares de la regeneración y posterior oseointegración.

Synthesis of Controlled-Size Silica Nanoparticles from Sodium Metasilicate and the Effect of the Addition of PEG in the Size Distribution.

Silica nanoparticles are widely studied in emerging areas of nanomedicine because they are biocompatible, and their surface can be modified to provide functionalization. The size is intrinsically related to the performance of the silica nanoparticles; therefore, it is important to have control over the size. However, the silica nanoparticles obtained from sodium metasilicate are less studied than those obtained from tetraethyl orthosilicate. Moreover, the methods of surface modification involve several steps after the synthesis. In this work, the effect of different concentrations of sodium metasilicate on the size of silica nanoparticles was studied. In the same way, we studied the synthesis of organically modified silica nanoparticles in a one-step method, using poly(ethylene glycol). The nanoparticles were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. It was found that the size distribution of the silica nanoparticles could be modified by changing the initial concentration of sodium metasilicate. The one-step surface-modification method caused a significant decrease in size distribution.

Poly(ethylene glycol) and Cyclodextrin-Grafted Chitosan: From Methodologies to Preparation and Potential Biotechnological Applications.

Chitosan, a polyaminosaccharide obtained by alkaline deacetylation of chitin, possesses useful properties including biodegradability, biocompatibility, low toxicity, and good miscibility with other polymers. It is extensively used in many applications in biology, medicine, agriculture, environmental protection, and the food and pharmaceutical industries. The amino and hydroxyl groups present in the chitosan backbone provide positions for modifications that are influenced by factors such as the molecular weight, viscosity, and type of chitosan, as well as the reaction conditions. The modification of chitosan by chemical methods is of interest because the basic chitosan skeleton is not modified and the process results in new or improved properties of the material. Among the chitosan derivatives, cyclodextrin-grafted chitosan and poly(ethylene glycol)-grafted chitosan are excellent candidates for a range of biomedical, environmental decontamination, and industrial purposes. This work discusses modifications including chitosan with attached cyclodextrin and poly(ethylene glycol), and the main applications of these chitosan derivatives in the biomedical field.

Validation of high performance liquid chromatography method for determination of meloxicam loaded PEGylated nanocapsules

abstract A method to ensure that an analytical method will produce reliable and interpretable information about the sample must first be validated, making sure that the results can be trusted and traced. In this study, we propose to validate an analytical high performance liquid chromatography (HPLC) method for the quantitation of meloxicam loaded PEGylated nanocapsules(M-PEGNC). We performed a validation study, evaluated parameters including specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. PEGylated nanocapsules were prepared by interfacial deposition of preformed polymer, and the particle size, polydispersity index, zeta potential, pH value and encapsulation efficiency were characterized. The proposed HPLC method provides selective, linear results in the range of 1.0-40.0 μg/mL; quantification and detection limits were 1.78 μg/mL and 0.59 μg/mL, respectively; relative standard deviation for repeatability was 1.35% and intermediate precision was 0.41% and 0.61% for analyst 1 and analyst 2, respectively; accuracy between 99.23 and 101.79%; robustness between 97.13 and 98.45% for the quantification of M-PEGNC. Mean particle diameters were 261 ± 13 nm and 249 ± 20 nm, polydispersity index was 0.15 ± 0.07 and 0.17 ± 0.06, pH values were 5.0 ± 0.2 and 5.2 ± 0.1, and zeta-potential values were -37.9 ± 3.2 mV e -31.8 ± 2.8 mV for M-PEGNC and placebo(B-PEGNC), respectively. In conclusion, the proposed analytical method is suitable for the quality control of M-PEGNC. Moreover, suspensions showed monomodal size distributions and low polydispersity index indicating high homogeneity of formulations with narrow size distributions, and appropriate pH and zeta potential. The extraction process was efficient for release of meloxicam from nanostructured systems.

resumo Para se assegurar que um método analítico produzirá informação confiável e interpretável sobre a amostra este deve ser inicialmente validado, tornando claro que os resultados podem ser confiados e rastreados. Neste estudo, propomos validar um método de cromatografia líquida de alta eficiência (CLAE) para a quantificação do meloxicam encapsulado em nanocápsulas PEGuiladas (M-PEGNC). Efetuamos a validação, avaliando parâmetros de especificidade, linearidade, limite de quantificação, limite de detecção, exatidão, precisão e robustez. As nanocápsulas PEGuiladas foram preparadas por deposição interfacial do polímero pré-formado e caracterizaram-se o tamanho da partícula, índice de polidispersão, potencial zeta, pH e eficiência de encapsulação. O método de CLAE proposto fornece resultados seletivos e lineares na faixa de 1,0-40,0 mg/mL; limites de quantificação e detecção de 1,78 mg/mL e 0,59 mg/mL, respectivamente; desvio padrão relativo para a repetibilidade de 1,35% e precisão intermediária de 0,41% e 0,61% para o analista 1 e analista 2, respectivamente; exatidão entre 99,23 e 101,79%; robustez entre 97,13 e 98,45% para a quantificação de M-PEGNC. Os diâmetros médios das partículas foram 261 ± 13 nm e 249 ± 20 nm; índice de polidispersão de 0,15 ± 0,07 e 0,17 ± 0,06, valores de pH de 5,0 ± 0,2 e 5,2 ± 0,1 e valores do potencial zeta de -37,9 ± 3,2 mV e -31,8 ± 2,8 mV para o M-PEGNC e o placebo(B-PEGNC), respectivamente. Concluindo, o método analítico proposto é adequado para o controle de qualidade do M-PEGNC. Além disso, suspensões mostraram distribuição de tamanho monomodal e baixo índice de polidispersão, indicando alta homogeneidade das formulações com distribuição estreita de tamanho, pH e potencial zeta apropriados. O processo de extração foi eficiente para a liberação do meloxicam dos sistemas nanoestruturados.

Antioxidant Capacity of Poly(Ethylene Glycol) (PEG) as Protection Mechanism Against Hydrogen Peroxide Inactivation of Peroxidases.

The ability of poly(ethylene glycol) (PEG) to protect enzymatic peroxidase activity was determined for horseradish peroxidase (HRP), versatile peroxidase (VP), commercial Coprinus peroxidase (BP), and chloroperoxidase (CPO). The operational stability measured as the total turnover number was determined for the four peroxidases. The presence of PEG significantly increased the operational stability of VP and HRP up to 123 and 195%, respectively, and dramatically increased the total turnover number of BP up to 597%. Chloroperoxidase was not protected by PEG, which may be due to the different oxidation mechanism, in which the oxidation is mediated by hypochlorous ion instead of free radicals as in the other peroxidases. The presence of PEG does not protect the enzyme when incubated only in the presence of H2O2 without reducing substrate. The catalytic constants (k cat) are insensitive to the presence of PEG, suggesting that the protection mechanism is not due to a competition between the PEG and the substrate as electron donors. On the other hand, PEG showed to have a significant antioxidant capacity. Thus, we conclude that the protection mechanism for peroxidases of PEG is based in its antioxidant capacity with which it is able scavenge or drain radicals that are harmful to the protein.

Extraction of natural red colorants from the fermented broth of Penicillium purpurogenum using aqueous two-phase polymer systems.

Safety concerns related to the increasing and widespread application of synthetic coloring agents have increased the demand for natural colorants. Fungi have been employed in the production of novel and safer colorants. In order to obtain the colorants from fermented broth, suitable extraction systems must be developed. Aqueous two-phase polymer systems (ATPPS) offer a favorable chemical environment and provide a promising alternative for extracting and solubilizing these molecules. The aim of this study was to investigate the partitioning of red colorants from the fermented broth of Penicillium purpurogenum using an ATPPS composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA). Red colorants partitioned preferentially to the top (PEG-rich phase). In systems composed of PEG 6,000 g/mol/NaPA 8,000 g/mol, optimum colorant partition coefficient (KC ) was obtained in the presence of NaCl 0.1 M (KC = 10.30) while the PEG 10,000 g/mol/NaPA 8,000 g/mol system in the presence of Na2 SO4 0.5 M showed the highest KC (14.78). For both polymers, the mass balance (%MB) and yield in the PEG phase (%ηTOP ) were close to 100 and 79%, respectively. The protein selectivity in all conditions evaluated ranged from 2.0-3.0, which shows a suitable separation of the red colorants and proteins present in the fermented broth. The results suggest that the partitioning of the red colorants is dependent on both the PEG molecular size and salt type. Furthermore, the results obtained support the potential application of ATPPS as the first step of a purification process to recover colorants from fermented broth of microorganisms.

Extraction protease expressed by Penicillium fellutanum from the Brazilian savanna using poly(ethylene glycol)/sodium polyacrylate/NaCl aqueous two-phase system.

The partitioning of protease expressed by Penicillium fellutanum from the Brazilian savanna in a novel inexpensive and stable aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and sodium polyacrylate (NaPA) was studied in this work using factorial design. The ATPS is formed by mixing both polymers with a salt (NaCl) and fermented broth of P. fellutanum. The effects of molar mass (2,000, 4,000, and 6,000 g ⋅ mol(-1)) and concentration (6, 8, and 10 wt%) of PEG and that of NaPA concentration (6, 8, and 10 wt%) on protease partitioning (K) at 25 °C were studied. A two-level factorial design (2(3)) was implemented. The effect of Na2 SO4 concentration (5, 10, and 15 wt%) on the reextraction of the enzyme was also analyzed. The partition coefficient K ranged from 77.51 to 1.21, indicating the versatility of the method. The reextraction was achieved with the addition of 5% Na2 SO4 , allowing the partitioning of the protease to the upper phase, whereas total proteins were directed to the bottom phase. The results of partitioning using the PEG/NaPA/NaCl system and that of the subsequent reextraction with Na2 SO4 suggest that this method can be used to purify proteases from fermented broth of P. fellutanum.

Research advances in major cereal crops for adaptation to abiotic stresses.

With devastating increase in population there is a great necessity to increase crop productivity of staple crops but the productivity is greatly affected by various abiotic stress factors such as drought, salinity. An attempt has been made a brief account on abiotic stress resistance of major cereal crops viz. In spite of good successes obtained on physiological and use molecular biology, the benefits of this high cost technology are beyond the reach of developing countries. This review discusses several morphological, anatomical, physiological, biochemical and molecular mechanisms of major cereal crops related to the adaptation of these crop to abiotic stress factors. It discusses the effect of abiotic stresses on physiological processes such as flowering, grain filling and maturation and plant metabolisms viz. photosynthesis, enzyme activity, mineral nutrition, and respiration. Though significant progress has been attained on the physiological, biochemical basis of resistance to abiotic stress factors, very little progress has been achieved to increase productivity under sustainable agriculture. Therefore, there is a great necessity of inter-disciplinary research to address this issue and to evolve efficient technology and its transfer to the farmers' fields.

Synthesis and MALDI-ToF characterization of dendronized poly(ethylene glycol)s

Well-defined hybrids of linear poly(ethylene glycol)s (PEGs) and dendritic polyesters were prepared via the dendronization of the alcohol end groups of the mono and difunctional linear PEGs. Though useful for rudimentary product characterization, GPC and NMR could not verify the overall structural purity of these linear-dendritic hybrids. On the other hand, the detailed data provided by MALDI-ToF mass spectrometry enabled confirmation of the high structural purity of the dendronized PEGs at each step of the dendronization procedure. The well-defined number of functionalities on these dendronized PEGs, renders them particularly useful for research in the biomedical sphere where functionality and purity are of the utmost importance. The MALDI-ToF mass spectrometric approach described herein represents a valuable technique for detailed monitoring of these dendronization reactions, as well as a variety of other polymer end group modifications.

Híbridos bem definidos de poli(etilenoglicol) lineares (PEGs) e poliésteres dendriméricos foram preparados via "dendronização" de álcool e grupos de PEGs lineares mono e bifuncionais. Embora úteis para a caracterização rudimentar de produtos, Cromatografia por Permeação em Gel e RMN podem não demonstrar a pureza estrutural global desses híbridos lineares dendríticos. Por outro lado, informações detalhadas provenientes de espectrometria de massas MALDI-ToF permitiram a confirmação de elevada pureza estrutural de PEGs "dendronizados" em cada passo do processo de "dendronização". O número de funcionalidades bem definidas destes PEGs "dendronizados", torna-os particularmente úteis para pesquisa na área biomédica, na qual funcionalidade e pureza são de grande importância. A abordagem de espectrometria de massas MALDI-ToF descrita aqui representa uma técnica valiosa para o monitoramento detalhado destas reações de "dendronização", bem como diversas modificações de outros polímeros e grupos.