Biodegradable Nanocomposites Research Articles

Controlled release of amoxicillin and antioxidant potential of gold nanoparticles-xanthan gum/poly (Acrylic acid) biodegradable nanocomposite

In the present study, the green microwave assisted synthesis of gold nanoparticles imbedded in XG/Poly(AA) biodegradable nanocomposite for controlled delivery of amoxicillin has been reported. The evidence of in-situ synthesis of gold nanoparticles by plant extract of Nepeta leucophylla as reducing agent inside the polymer matrix, grafting of acrylic acid (AA) onto backbone XG, surface morphology, crystallinity, thermal properties and loading of amoxicillin inside the MW-AuNPs/XG/Poly(AA) nanocomposite are investigated using various characterization techniques, such as, UV–Vis, XRD, FTIR, TGA/DSC, FE-SEM, EDX, TEM, DLS and Nitrogen adsorption-desorption isotherms (BET studies). The biodegradation test of synthesized nanocomposite has been performed by soil burial method for 75 days. The evidence of biodegradability of MW-AuNPs/XG/Poly(AA) nanocomposite is confirmed by FTIR and FE-SEM micrographs. The release profiles of amoxicillin drug from synthesized nanocomposite has been investigated for different pH (2.4, 7.0 and 9.2) at 37°C using Korsmeyer–Peppas model. Here, the maximum drug loading efficiency is found to be about 85% and release of drug is large in basic medium as compare to acidic and neutral. It is expected that the present work may provide a noble method for synthesis of biodegradable nanocomposite with decent antioxidant potential for controlled release of amoxicillin.

Creep behavior of Biodegradable Triple-component Nanocomposites Based on PLA/PCL/bioactive Glass for ACL Interference Screws.

Short-time creep behaviorfor aseries of biodegradable nanocomposites, which areused as implantable devices inthe body, is a crucial factor.The present study aimed to investigate the effect of bioactive glass nanoparticles (BGn) on creep and creep-recovery behaviors of polylactic acid/polycaprolactone (PLA/PCL) blends at different given loads and different applied temperatures. A series of biodegradable nanocomposites consisted of PLA/PCL blends (comprising 80 parts PLA and 20 parts PCL) with different amounts of modified-BGn (m-BGn) fillers were prepared using the evaporated solvent casting technique. Creep and creep-recovery behaviors of all specimens were studied at different valuable stressesof 3 and 6 MPa and different given temperatures of 25 and 37°C. In all cases, m-BGn improved the creep resistance of the nanocomposites due to the retardation effect during the creep behaviors of the nanocomposite systems. The obtained results in terms of creep and creep-recovery properties determined that the nanocomposites of PLA/PCL/m-BGn can satisfy the required conditions of an appropriate anterior cruciate ligament reconstruction (ACL-R) screw. The obtained results confirmed that the BGn plays an impeding role in the movement of PLA/PCL chains leading to in increase the creep resistance. According to the results, it was determined that the nanocomposites of PLA/PCL and m-BGn can satisfy the required circumstances of a proper ACL-R screw.

Full biodegradable elastomeric nanocomposites fabricated by chitin nanocrystal and poly(caprolactone-diol citrate) elastomer

Chitin nanocrystal is a biocompatible and biodegradable nanofiller, with great potential in enhancing the mechanical and biological properties of polymers. Poly(caprolactone-diol citrate) is a kind of citrate-based biodegradable elastomer prepared by an additive-free melt polycondensation of polycaprolactone-diol and citric acid coupled with subsequent thermocuring. Here, a facile casting/evaporation method was utilized to prepare full biodegradable poly(caprolactone-diol citrate)/chitin nanocrystal nanocomposites, and their structure and properties were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, uniaxial tensile test, dynamic mechanical analysis, surface wettability and swelling analysis, thermogravimetric analysis, in vitro degradation, and cytocompatibility test. The results showed the chitin nanocrystals were uniformly distributed in the poly(caprolactone-diol citrate) matrix; with increasing chitin nanocrystal loading, the tensile modulus and strength significantly increased; furthermore, the incorporation of chitin nanocrystals endowed the poly(caprolactone-diol citrate) with more hydrophilicity, lower swelling in phosphate buffered saline solution, slow degradation rate, and greatly improved cytocompatibility. Thus, the chitin nanocrystal was a good bio-based nanofiller that could be used to tune the properties of poly(caprolactone-diol citrate) degradable bioelastomer.

Selective localization of starch nanocrystals in the biodegradable nanocomposites probed by crystallization temperatures

Starch nanocrystal (SNC), was used as the third component to prepare nanocomposites with biodegradable poly(β-hydroxybutyrate)/poly(butylene succinate) (PHB/PBS) blend. The results reveal that SNC shows strong nucleation to the two matrix polymers. However, the crystallization temperature of PHB is highly dependent on the SNC loadings, whereas that of PBS not. This is because SNCs have preferential localization in the immiscible matrix polymers: mainly dispersed in the continuous PHB phase and on PHB/PBS phase interfaces. Therefore, alteration trend of crystallization temperatures can be used as good probe to evaluate selective localization of SNCs in the immiscible blends containing two semicrystalline polymers. The nucleation activities of SNCs, and their interaction energy densities in the two polyesters, as well as the tensile behaviors of ternary nanocomposites, were then detected, aiming at establishing a simple route to prepare green nanocomposites with tailorable multi-phase morphology and balanced mechanical properties using starch and biodegradable aliphatic polyester blends.

The optimization of physico-mechanical properties of bionanocomposite films based on gluten/ carboxymethyl cellulose/ cellulose nanofiber using response surface methodology

Abstract In the present study, new biodegradable nanocomposite films were produced. The effect of wheat gluten (WG) (1–2.5 wt%), carboxymethyl cellulose (CMC) (0.5–1 wt%) and cellulose nanofiber (CNF) (0-10 wt% based on gluten and CMC biopolymers solid matter in each formula) concentration on water vapor permeability (WVP), mechanical and color properties of the biodegradable nanocomposites were investigated using response surface methodology (RSM). Regression models were also developed for all responses as a function of linear, interaction and quadratic terms of WG/CMC/CNF concentrations. The optimum point with 1 wt% gluten, 0.686 wt% CMC and 8.549 wt% CNF for a maximum desirability of 0.878 was obtained. Furthermore, the microstructure, surface topography and the distribution quality of cellulose nanofiber in the biopolymer matrix were evaluated by scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X ray diffraction (XRD) analysis.

Graphene-Reinforced Biodegradable Resin Composites for Stereolithographic 3D Printing of Bone Structure Scaffolds

A biodegradable UV-cured resin has been fabricated via stereolithography apparatus (SLA). The formulation consists of a commercial polyurethane resin as an oligomer, trimethylolpropane trimethacrylate (TEGDMA) as a reactive diluent and phenylbis (2, 4, 6-trimethylbenzoyl)-phosphine oxide (Irgacure 819) as a photoinitiator. The tensile strength of the three-dimensional (3D) printed specimens is 68 MPa, 62% higher than that of the reference specimens (produced by direct casting). The flexural strength and modulus can reach 115 MPa and 5.8 GPa, respectively. A solvent-free method is applied to fabricate graphene-reinforced nanocomposite. Porous bone structures (a jawbone with a square architecture and a sternum with a round architecture) and gyroid scaffold of graphene-reinforced nanocomposite for bone tissue engineering have been 3D printed via SLA. The UV-crosslinkable graphene-reinforced biodegradable nanocomposite using SLA 3D printing technology can potentially remove important cost barriers for personalized biological tissue engineering as compared to the traditional mould-based multistep methods.

A novel electromagnetic biodegradable nanocomposite based on cellulose, polyaniline, and cobalt ferrite nanoparticles

Biodegradable, antimicrobial, and semiconducting cellulosic composite was synthesized by in-situ polymerization of polyaniline in the presence of cellulose. The cobalt ferrite nanoparticles (CFO-NPs) were added during the polymerization process to acquire this composite magnetic property. The CFO-NPs were prepared by sol–gel method with average particles size less than 50 nm. The nanocomposites were characterized by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). In addition, their magnetic, dielectric constant, dielectric loss, and conductivity behaviors were studied. The magnetization (Ms) and conductivity increased up to 3.7 emu/g and 3.5 × 10−3 S/cm, respectively, with increasing CFO-NPs content. The prepared electromagnetic nanocomposite exhibits highly efficient biodegradability and antimicrobial activity against Escherichia coli, Bacillus subtilis, and Candida albicans. The antimicrobial activity increased with increasing CFO-NPs while the biodegradability decreased.

Fabricating Hybrid Microsphere Substrate Based PLGA‐CNT with In Situ Drug Release: Characterization and In Vitro Evaluation

AbstractA drug loaded hard tissue nanocomposite with poly‐lactic‐co‐glycolic acid (PLGA) and multi‐walled carbon nanotubes (MWCNT's) fabricated using emulsification‐evaporation and subsequent sintering techniques. Desirable strength via presence of optimum amount and good dispersion of carbon nanotubes was achieved. Results show that by adding only 3% MWCNT's, the compressive strength and modulus was significantly increased compared to pure PLGA composite. SEM images showed adequate CNTs attachment and diffusion in the surfaces of nano and microspheres with uniform orientation. FTIR and X‐ray analyses firmly verified ingredients combination in substrates and evidenced drug and CNTs in their structure. This study explains the possibility of fabricating multifunctional, biocompatible, biodegradable nanocomposites as a hard tissue with controlled drug release.

Biodegradable PBAT-Based Nanocomposites Reinforced with Functionalized Cellulose Nanocrystals from Pseudobombax munguba: Rheological, Thermal, Mechanical and Biodegradability Properties

Cellulose nanocrystals (CNC) were isolated from Munguba (Pseudobombax munguba) fibers and then functionalized with octadecyl isocyanate. Nanocomposites based on poly(butylene adipate-co-terephthalate) (PBAT) were prepared with different concentrations of cellulose nanocrystals (3, 5 and 7 wt%). We show that the addition of functionalized CNC leads to PBAT-based nanocomposites with enhanced thermal, rheological and mechanical performances, maintaining the biodegradability of the matrix. The better properties of the nanocomposites were related to the optimal amount and the uniform dispersion of CNC in PBAT. The study here presented expands the application of Munguba fibers, exploring their use to prepare PBAT-based biodegradable nanocomposites with improved properties. These nanocomposites have potential for replacement the conventional polymers in future applications with the advantage of exhibiting biodegradability.

Synthesis and study of mechanical and fire retardant properties of (carboxymethyl cellulose -g-polyacrylonitrile)/montmorillonite biodegradable nanocomposite

Despite abundant researches on petroleum based polymer nanocomposites over micro and macro composites, these nanocomposites suffer from deprived biodegradability, highly inherent flammability and less mechanical strength. The present work describes the preparation of a biodegradable nanocomposite based on carboxymethyl cellulose-g-polyacrylonitrile (CMC-g-PAN) and montmorillonite (MMT) nanoclay by using ammonium persulfate (APS) as an initiator, methylene bis-acrylamide (MBA) as a crosslinker via emulsifier free emulsion polymerisation. The formation of the nanocomposites was confirmed by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Transmission electron microscope (TEM) analysis. The formation of CMC-g-PAN copolymer was confirmed by means of proton nuclear magnetic resonance (1H NMR) spectra. The improvement in thermal stability of the nanocomposites over copolymer was outstanding. More importantly, incorporating MMT enables the nanocomposite to achieve a dramatically reduced peak heat release rate of 536 ± 03 kW m−2 shown in cone calorimetry tests and higher limiting oxygen index (LOI) value indicating improved fire retardancy. In addition, the tensile strength of the nanocomposite was also increased by around 41% with 5% w/v MMT contents. This is explained on the basis of strong interfacial adhesion between CMC and MMT through PAN. Meanwhile for its better commercialization, the eco-friendly nature was studied via biodegradation.

Effect of ZnO nanoparticles on the mechanical, barrier and optical properties of thermoplastic cationic starch/montmorillonite biodegradable films

In this study, various amounts of nanoclay montmorillonite (MMT) and ZnO nanopowders were used to analyze the properties of biodegradable nanocomposites of cationic starch (CS). Nanocomposites are produced by solvent casting method. The structure of CS-MMT nanocomposite films that contain 3% montmorillonite was exfoliated and was proved by XRD test. New hydrogen bonds were successfully formed between the CS hydroxyl groups and nanofillers and this was proved by FTIR test. The water vapor permeability and the UV light transmittance of the nanocomposites reduced after the contents of MMT and ZnO increased. ∆E and opacity of the nanocomposites enhanced after the amount of ZnO increased. Tensile strength (TS) of nanocomposites increased after the incorporation of ZnO and MMT nanoparticles although the elongation at break was diminished. Results showed that the 3 and 0.7 wt% amounts of montmorillonite and ZnO nanopowders were sufficient in order to acquire a well-moderated mechanical behavior in plastic and elastic regions, and they also cause good improvements in barrier and optical properties.

Polycaprolactone/organoclay biodegradable nanocomposites: dissimilar tendencies of different clay modifiers

In this work, biodegradable nanocomposites based on polycaprolactone (PCL) reinforced with 2.5, 5.0 and 7.5 wt.% of two different clays, a commercial organo-clay (Cloisite 20A, C20A) and a laboratory modified bentonite with tributylhexadecyl phosphonium bromide (bTBHP), were prepared by melt intercalation followed by compression molding. The study contemplates the analysis of chemical (Infrared Spectrometry, FTIR), morphological (X-Ray Diffractometry, XRD, Scanning Electron Microscopy, SEM, and Transmission Electron Microscopy, TEM), rheological, thermal (Differential Scanning Calorimetry, DSC, and Thermogravimetrical Analysis, TGA) and mechanical properties (tensile tests), which are important properties for packaging applications.In previous works, we concluded that higher clay dispersion degree inside the PCL matrix is expected when clays with large interlayer distance, strong hydrophobicity and strong processing stability are used. In the present work, the opposite result was obtained. Although the phosphonium treated clay (bTBHP) showed the largest interlayer distance (d001), strongest hydrophobicity and the best processing stability, the clay dispersion degree inside PCL was worse than in the case of the alkylammonium treated clay (C20A). PCL/bTBHP nanocomposites showed weaker mechanical properties in comparison with PCL/C20A ones, which is in accordance with the morphological analysis. On the other hand, the thermal properties of the matrix were not substantially affected by clay incorporation in both nanocomposites.

Recent Developments in Food Packaging Based on Nanomaterials.

The increasing demand for high food quality and safety, and concerns of environment sustainable development have been encouraging researchers in the food industry to exploit the robust and green biodegradable nanocomposites, which provide new opportunities and challenges for the development of nanomaterials in the food industry. This review paper aims at summarizing the recent three years of research findings on the new development of nanomaterials for food packaging. Two categories of nanomaterials (i.e., inorganic and organic) are included. The synthetic methods, physical and chemical properties, biological activity, and applications in food systems and safety assessments of each nanomaterial are presented. This review also highlights the possible mechanisms of antimicrobial activity against bacteria of certain active nanomaterials and their health concerns. It concludes with an outlook of the nanomaterials functionalized in food packaging.

Characterization, thermal degradation kinetics, and morphological properties of a graphene oxide/poly (vinyl alcohol)/starch nanocomposite

In this study, we synthesized a biodegradable nanocomposite containing starch, polyvinyl alcohol (PVA), and graphene oxide (GO). The non-isothermal degradation kinetics of this nanocomposite was investigated by thermogravimetric analysis. Accordingly, the kinetic parameters, such as activation energy (Ea), exponential factor (A), rate constant (k), and degradation time, were calculated. The calculated kinetic parameters are used to predict the lifetime. The master plot analysis showed that the kinetic function of the thermal degradation changed from A2 to A3 upon addition of GO to the PVA/starch blend. The reaction heat (ΔH), glass transition temperature (Tg), and melting point (Tm) of the PVA/starch film and PVA/starch/GO nanocomposite were determined by the differential scanning calorimetry analysis. Also, the Tg values were determined by dynamic mechanical thermal analyzer. The changes in peak bandwidth, strength, and frequency in the samples are identified by FTIR spectra. The structure and morphology of the nanocomposite were studied by X-ray diffraction analysis and field emission scanning electronic microscope.

Biodegradable nanocomposite of glycerol citrate polyester and ultralong hydroxyapatite nanowires with improved mechanical properties and low acidity

Glycerol citrate polyester based on the condensation of glycerol and citric acid has a great potential in biomedical applications owing to biocompatible monomers and biodegradation properties. However, the applications of glycerol citrate polyester are impaired by its poor mechanical properties and high acidity caused by citric acid produced in the degradation process. In this work, a new kind of nanocomposite has been developed using ultralong hydroxyapatite (HAP) nanowires as the “skeleton”, and strongly bound glycerol citrate polyester as the “muscle”. The ultralong HAP nanowires interweave with each other to form a three-dimensional nanoporous network, and glycerol citrate polyester is homogeneously distributed in the nanoporous network. Owing to the reinforcement of ultralong HAP nanowires, the mechanical properties of the as-prepared nanocomposite are significantly improved compared with the pure glycerol citrate polyester, and the tensile strength even reaches to the level of human cortical bones. Furthermore, the acidity of the aqueous solution after degradation is neutralized by the reaction between citric acid and ultralong HAP nanowires, and the pH value can be stabilized. The as-prepared nanocomposite can solve some problems of the pure glycerol citrate polyester, and shows promising applications in the biomedical field.

Fabrication and evaluation of a nerve guidance conduit capable of Ca2+ ion release to accelerate axon extension in peripheral nerve regeneration.

In this study, biodegradable nanocomposites consisting of poly (glycerol sebacate) (PGS) elastomeric matrix and the reinforcing phase of calcium titanate (CaTiO3 ) nanoparticles were fabricated as a nerve guidance conduit (NGC) for peripheral nerve regeneration. CaTiO3 nanoparticles were synthesized via the sol-gel method and calcined at 800°C for 60 min. PGS elastomer was synthesized via the polycondensation reaction of glycerol and sebacate (1:1) and 2.5 and 5 wt. percentages of the synthesized CaTiO3 nanoparticles were added to the PGS prepolymer solution. The composites obtained were heated in order to make crosslinks in the pre-polymer. CaTiO3 nanoparticles, PGS elastomer, and the composites fabricated were characterized in terms of their structural, chemical, physical, mechanical, and cell response properties to evaluate the feasibility of using the nanocomposite for NGC applications. The results indicated that CaTiO3 nanoparticles were 50 nm in size. When the nanoparticles were added to the PGS, the elastic modulus and tensile strength of the nanocomposite reached values of about 1 and 0.5 MPa, respectively that are near those of natural nerves. The degradation behavior and swelling of the nanocomposites, as compared with those of the PGS elastomer, were controlled by introducing CaTiO3 into the PGS, which swelling limitation could prevent nerve compression. It was observed that Ca2+ ions established chemical bonds with PGS, which led to high crosslink densities that, in turn, contribute to improved mechanical properties of the composite. The Ca2+ ions released from the nanocomposite samples were in the nontoxic range. The PC12 cell line on the surface of the nanocomposite specimens showed good cell adhesion and proliferation with improved axon outgrowth and extension. Based on the results obtained the fabricated PGS/CaTiO3 nanocomposite may be recommended as a suitable NGC with desirable effects on peripheral nerve regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2181-2189, 2018.

Effect of the addition of polyester-grafted-cellulose nanocrystals on the shape memory properties of biodegradable PLA/PCL nanocomposites

In this work the thermally-activated shape memory response of biodegradable nanocomposites based on PLA/PCL blend reinforced with different type of cellulose nanocrystals has been reported, and compared with those of the neat matrix, at the same transition temperature of 55 °C and at the same different deformations, 50%, 100% and 150%. In particular, cellulose nanocrystals have been synthesized and then functionalized by “grafting from” reaction by ring opening polymerization of both PLLA and PCL using the OH groups onto the cellulose nanocrystals surface as initiators for the reaction. The morphology, thermal and mechanical analysis have been performed in order to obtain the parameters for the thermo-mechanical shape memory cycles. Moreover, the addition of the CNC-based nanofillers on the compatibility of PLA-PCL blends in 70:30 proportion has been evaluated. All the biodegradable nanocomposite formulations showed excellent shape memory response, similar to those of the neat matrix, with strain recovery ratio and strain fixity ratio higher than 80% and 90%, respectively. This fact indicates that in this case, the shape memory response of the nanocomposites is mainly controlled by the response of the neat blend and they are slightly influenced by the increase of compatibility between the components of the blend. In addition, all nanocomposite films were fully disintegrated under composting conditions confirming their biodegradable nature, obtaining that the presence of CNC-based nanofillers speeds up the disintegration rate of the nanocomposites in comparison with the pure matrix.

Bilayer biocomposites based on coated cellulose paperboard with films of polyhydroxybutyrate/cellulose nanocrystals

Fil: Seoane, Irene Teresita. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingenieria. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales; Argentina

Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite

In this work, the effect of the addition of different amount of nanosized hydroxyapatite (nHA) on the shape memory behavior of blends based on poly (lactic acid) (PLA) and poly (ε-caprolactone) (PCL) has been studied. In particular PLA/PCL blend with 70 wt % PLA has been reinforced with 0.5, 1 and 3 wt % nHA. Moreover, the relationship between the morphology and the final properties of the nanocomposites has been investigated by field emission scanning electron microscopy, confocal Raman spectroscopy and atomic force microscopy. In particular, PeakForce has been used to study quantitative nanomechanical properties of the multifunctional materials leading to conclusion that nHA increase the phase separation between PLA and PCL as well as act as reinforcements for the PCL-rich phase of the nanocomposites. Furthermore, excellent thermally-activated shape memory response has been obtained for all the nanocomposites at 55 °C. Finally, the disintegration under composting conditions at laboratory scale level was studied in order to confirm the biodegradable character of these nanocomposites. Indeed, these materials are able to be used for biomedical issues as well as for packaging applications where both thermally-activated shape memory effect and biodegradability are requested.

Supramolecular Approach for Efficient Processing of Polylactide/Starch Nanocomposites.

All-biobased and biodegradable nanocomposites consisting of poly(l-lactide) (PLLA) and starch nanoplatelets (SNPs) were prepared via a new strategy involving supramolecular chemistry, i.e., stereocomplexation and hydrogen-bonding interactions. For this purpose, a poly(d-lactide)-b-poly(glycidyl methacrylate) block copolymer (PDLA-b-PGMA) was first synthesized via the combination of ring-opening polymerization and atom-transfer radical polymerization. NMR spectroscopy and size-exclusion chromatography analysis confirmed a complete control over the copolymer synthesis. The SNPs were then mixed up with the copolymer for producing a PDLA-b-PGMA/SNPs masterbatch. The masterbatch was processed by solvent casting for which a particular attention was given to the solvent selection to preserve SNPs morphology as evidenced by transmission electron microscopy. Near-infrared spectroscopy was used to highlight the copolymer–SNPs supramolecular interactions mostly via hydrogen bonding. The prepared masterbatch was melt-blended with virgin PLLA and then thin films of PLLA/PDLA-b-PGMA/SNPs nanocomposites (ca. 600 μm) were melt-processed by compression molding. The resulting nanocomposite films were deeply characterized by thermogravimetric analysis and differential scanning calorimetry. Our findings suggest that supramolecular interactions based on stereocomplexation between the PLLA matrix and the PDLA block of the copolymer had a synergetic effect allowing the preservation of SNPs nanoplatelets and their morphology during melt processing. Quartz crystal microbalance and dynamic mechanical thermal analysis suggested a promising potential of the stereocomplex supramolecular approach in tuning PLLA/SNPs water vapor uptake and mechanical properties together with avoiding PLLA/SNPs degradation during melt processing.