21 research outputs found

    Biomaterials Based on Organic Polymers and Layered Double Hydroxides Nanocomposites: Drug Delivery and Tissue Engineering

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    The development of biomaterials has a substantial role in pharmaceutical and medical strategies for the enhancement of life quality. This review work focused on versatile biomaterials based on nanocomposites comprising organic polymers and a class of layered inorganic nanoparticles, aiming for drug delivery (oral, transdermal, and ocular delivery) and tissue engineering (skin and bone therapies). Layered double hydroxides (LDHs) are 2D nanomaterials that can intercalate anionic bioactive species between the layers. The layers can hold metal cations that confer intrinsic biological activity to LDHs as well as biocompatibility. The intercalation of bioactive species between the layers allows the formation of drug delivery systems with elevated loading capacity and modified release profiles promoted by ion exchange and/or solubilization. The capacity of tissue integration, antigenicity, and stimulation of collagen formation, among other beneficial characteristics of LDH, have been observed by in vivo assays. The association between the properties of biocompatible polymers and LDH-drug nanohybrids produces multifunctional nanocomposites compatible with living matter. Such nanocomposites are stimuli-responsive, show appropriate mechanical properties, and can be prepared by creative methods that allow a fine-tuning of drug release. They are processed in the end form of films, beads, gels, monoliths etc., to reach orientated therapeutic applications. Several studies attest to the higher performance of polymer/LDH-drug nanocomposite compared to the LDH-drug hybrid or the free drug

    Limiting content of trivalent iron to form organic-inorganic single-phase layered double hydroxides hybrids by coprecipitation

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    International audienceThe diterpenoid abietate (ABI) ion, the conjugate base of the phytochemical abietic acid, was intercalated into a series of layered double hydroxides (LDH) with Mg2FeyAl(1-y) composition envisioning the preparation of drug delivery systems. Experimental parameters were evaluated to achieve organic-inorganic hybrid iron-based LDH as single-phases enriched with such endogenous metal, by coprecipitation method. A set of multiple physicochemical techniques was used for a detailed characterization of the hybrid materials. The assignment of ABI anions spectroscopic signals was inspected by density functional theory (DFT) calculations to address the ABI structural integrity after intercalation. Single-phase LDH-ABI materials having 41–48 wt% of the bioactive species were formed for compositions with y ≤ 0.5. Above the threshold Fe3+/Al3+ molar ratio equal to 1 (y > 0.5), multi-phases were observed in LDH-ABI samples, with the ABI amount corresponding to 33–22 wt%. Higher loading values were hindered by considering the steric constraint of ABI. Thermal analysis and spectroscopic data indicated that the chemical integrity of the sensitive abietic acid was preserved after its intercalation. These results should be inspiring for the design of delivery systems with multiple bio-functionalities based on iron-enriched LDH carriers

    Thermal decomposition of a layered double hydroxide as a bottom up approach for the synthesis of metallic nanoparticles embedded in carbon structures

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    International audienceIn the present study, the thermal behaviour of a layered double hydroxide (LDH) intercalated with a carboxymethylcellulose (CMC) polymer was evaluated to inspect the effect of the temperature on the chemical processes that occur during its decomposition under a nitrogen atmosphere, ranging from 500 to 1000 1C, as well as the product properties. The intercalation compound (LDH-CMC) proved to be a suitable precursor to develop inorganic nanocomposites based on Ni metallic nanoparticles (Ni-MNPs) embedded in a carbonaceous matrix by a bottom-up strategy involving a carbothermal reaction. Considering the temperature effect on the LDH-CMC decomposition processes, as well as the dispersion of metallic and carbon sources at the nanoscale level favoured by the intercalated structure, the simple synthetic approach reported in this work permits fine tuning of the production of valuable phases. The nanocomposites with ordered carbonaceous structures and transition metallic nanoparticles are interesting functional materials for electrocatalysis

    New insights into two ciprofloxacin-intercalated arrangements for layered double hydroxide carrier materials

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    International audienceThis paper describes the intercalation of ciprofloxacin (CIP), a bactericidal antibiotic, into the interlayer space of layered double hydroxides (LDHs). To counter the problem of bacterial resistance and also to improve the properties of the CIP drug, the drug carrier approach promises significant benefits. Through the tight control over the synthesis parameters, particularly the amounts of CIP with respect to aluminum ions, two different LDH-CIP-intercalated structures were obtained with significantly different interlayer distances, namely, 21 and 32 Å. The samples were fully characterized in terms of composition, structure, and morphology. Interestingly, the structure with the largest interlayer distance incorporated both CIP anions and Al(CIP)3 complex, exhibiting the possibility to increase the CIP drug loading beyond the anionic-exchange capacity of the LDH carrier. In vitro release in a simulated intestinal fluid (phosphate-buffered solution at pH 7.5) confirmed that LDH was a potentially efficient carrier to deliver CIP in a sustained manner via the anion- exchange mechanism. Different release rates were observed depending on the intercalated structure, which were also influenced by the morphological characteristics

    Special session in honor of Antonio Carlos Massabni

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    The present issue of International Journal of Advances in Medical Biotechnology (IJAMB) introduces a set of five papers elaborated by Prof. Antonio Carlos Massabni and students that have attended a graduate course nominated Seminars of Integration from the Postgraduate Program in Biotechnology of the University of Araraquara (UNIARA), Araraquara, Brazil. The authors have focused on the impact of Industry 4.0 technologies on Biotechnology as well as the chance for future professionals and the work relations in this context. In other papers, the importance of biotechnology in the development of vaccines, antibiotics, hormones and scaffolds for regenerative medicine are discussed. This issue is dedicated in honor of Prof. Massabni for his commitment with teaching, research and administrative duties

    EXTRACTION AND CHARACTERIZATION OF BIOPOLYMERS FROM EXOSKELETON RESIDUES OF THE AMAZON CRAB DILOCARCINUS PAGEI

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    Chitin is the second most abundant biopolymer worldwide and is found in a large variety of animals. Besides shrimps, other species possess significant chitin contents in their external non-edible fraction, thus allowing them to be also economically viable sources of this macromolecule. According to mass-loss evaluation of crab residues, 78.4% of the mass is comprised of CaCO3 and 21.6% associated to the organic phase. The chitin content found was 8.0% of the residue’s initial mass and after the deacetylation step, the average chitosan yield was 5.0% of the initial residue mass. The thermal decomposition profiles of obtained chitin and chitosan samples were characteristic of biopolymers, exhibiting non-oxidative (190–360°C) and oxidative (340–670°C) events of mass loss. Vibrational spectroscopic analysis showed that the degrees of deacetylation of the obtained chitosan samples were time-dependent and between 68.4 and 81.9%

    Mesoporous carbon derived from a biopolymer and a clay: Preparation, characterization and application for an organochlorine pesticide adsorption

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    The production of carbon-based materials is a field of intense scientific research due to the diversity of potential applications that this kind of material presents. In this paper, it is reported the synthesis of porous carbonaceous material (PCM) based on the pyrolysis at 850 degrees C of a composite made of Laponite (commercially available synthetic clay) and Cassava starch, followed by clay removal through acid digestion. The Laponite presence influenced the structural order and textural properties of the pyrolytic carbon formed. After pyrolysis and acid digestion of clay, it was obtained a material with a partial graphitic structure containing majorly sp(2) bounded carbon atoms, that has almost twice the specific surface area and up to 20 times more mesopore volume than the carbonaceous material obtained without the clay. The adsorbent potential of PCM was evaluated by adsorption of Dicamba, an organochlorine pesticide, from aqueous solutions. The PCM exhibits a high Dicamba removal efficiency, with a maximum adsorption capacity of 251.9 mg g(-1) related to a pseudo-second-order kinetic adsorption model with a strong pH dependence. (C) 2016 Elsevier Inc. All rights reserved.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - CAPESFundacao de Amparo a Pesquisa do Estado de Minas Gerais - FapemigFundacao de Amparo a Pesquisa do Estado de Sao Paulo - FapespConselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPqFAPEMIGUniv Fed Vicosa, Inst Ciencias Exatas & Tecnol, Campus Rio Paranaiba,Rodovia BR 354,Km 310, BR-38810000 Rio Paranaiba, MG, BrazilUniv Sao Paulo, Inst Quim, Dept Quim Fundamental, Ave Lineu Prestes 748, BR-05508000 Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Exatas & Terra, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Exatas & Terra, Rua Sao Nicolau 210, BR-09913030 Diadema, SP, BrazilFAPEMIG: APQ-00706-11FAPEMIG: CEX - RED-00010-14FAPESP: 2011/50318-1CNPq: 312384/2013-0Web of Scienc
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