In this study, silver nanoparticles (Ag-NPs) were synthesized using a green physical synthetic route into the lamellar space of montmorillonite (MMT)/chitosan (Cts) utilizing the ultraviolet (UV) irradiation reduction method in the absence of any reducing agent or heat treatment. Cts, MMT, and AgNO(3) were used as the natural polymeric stabilizer, solid support, and silver precursor, respectively. The properties of Ag/MMT/Cts bionanocomposites (BNCs) were studied as the function of UV irradiation times. UV irradiation disintegrated the Ag-NPs into smaller sizes until a relatively stable size and size distribution were achieved. Meanwhile, the crystalline structure and d-spacing of the MMT interlayer, average size and size distribution, surface morphology, elemental signal peaks, functional groups, and surface plasmon resonance of Ag/MMT/Cts BNCs were determined by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, Fourier transform infrared, and UV-visible spectroscopy. The antibacterial activity of Ag-NPs in MMT/Cts was investigated against Gram-positive bacteria, ie, Staphylococcus aureus and methicillin-resistant S. aureus and Gram-negative bacteria (ie, Escherichia coli) by the disk diffusion method on Muller-Hinton Agar at different sizes of Ag-NPs. All of the synthesized Ag/MMT/Cts BNCs were found to have high antibacterial activity. These results show that Ag/MMT/Cts BNCs can be useful in different biologic research and biomedical applications, such as surgical devices and drug delivery vehicles.
This study describes a sago starch-based film by incorporation of cinnamon essential oil (CEO) and nano titanium dioxide (TiO2-N). Different concentrations (i.e., 0%, 1%, 3%, and 5%, w/w) of TiO2-N and CEO (i.e., 0%, 1%, 2%, and 3%, v/w) were incorporated into sago starch film, and the physicochemical, barrier, mechanical, and antimicrobial properties of the bionanocomposite films were estimated. Incorporation of CEO into the sago starch matrix increased oxygen and water vapor permeability of starch films while increasing TiO2-N concentration decreased barrier properties. Moisture content also decreased from 12.96% to 8.04%, solubility in water decreased from 25% to 13.7%, and the mechanical properties of sago starch films improved. Sago starch bionanocomposite films showed excellent antimicrobial activity against Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus. Results also showed that incorporation of TiO2-N and CEO had synergistic effects on functional properties of sago starch films. In summary, sago starch films incorporated with both TiO2-N and CEO shows potential application for active packaging in food industries such as fresh pistachio packaging.
Combination of bioactive material such as hydroxyapatite (HAp) with antibacterial agents would have great potential to be used as bone implant materials to avert possible bacterial infection that can lead to implant-associated diseases. The present study aimed to develop an antibacterial silver nanoparticle-decorated hydroxyapatite (HAp/AgNPs) nanocomposite using chemical reduction and thermal calcination approaches. In this work, natural HAp that was extracted from chicken bone wastes is used as support matrix for the deposition of silver nanoparticles (AgNPs) to produce HAp/AgNPs nanocomposite. XRD, FESEM-EDX, HRTEM, and XPS analyses confirmed that spherical AgNPs were successfully synthesized and deposited on the surface of HAp particles, and the amount of AgNPs adhered on the HAp surface increased with increasing AgNO3 concentration used. The synthesized HAp/AgNPs nanocomposites demonstrated strong antibacterial activity against Staphylococcus aureus bacteria, where the antibacterial efficiency is relied on the amount and size of deposited AgNPs. In addition, the in vitro bioactivity examination in Hank's balanced salt solution showed that more apatite were grown on the surface of HAp/AgNPs nanocomposite when AgNO3 concentration used >1 wt.%. Such nanocomposite with enhanced bioactivity and antibacterial properties emerged as a promising biomaterial to be applied for dentistry and orthopedic implantology.
The efficiency of the extraction and removal of pollutants from food and the environment has been an important issue in analytical science. By incorporating inorganic species into an organic matrix, a new material known as an organic-inorganic hybrid material is formed. As it possesses high selectivity, permeability, and mechanical and chemical stabilities, organic-inorganic hybrid materials constitute an emerging research field and have become popular to serve as sorbents in various separaton science methods. Here, we review recent significant advances in analytical solid-phase extraction employing organic-inorganic composite/nanocomposite sorbents for the extraction of organic and inorganic pollutants from various types of food and environmental matrices. The physicochemical characteristics, extraction properties, and analytical performances of sorbents are discussed; including morphology and surface characteristics, types of functional groups, interaction mechanism, selectivity and sensitivity, accuracy, and regeneration abilities. Organic-inorganic hybrid sorbents combined with extraction techniques are highly promising for sample preparation of various food and environmental matrixes with analytes at trace levels.
In this study, tunable Schiff's base-cross-linked chitosan-glutaraldehyde (CS-GLA) was modified and applied to remove reactive red 120 (RR120) dye from an aqueous solution. Different ratios of TiO2 nanoparticles, such as 25% TiO2 nanoparticles (CS-GLA/TNC-25) and 50% TiO2 nanoparticles (CS-GLA/TNC-50), were loaded into the CS-GLA's molecular structure. The adsorptive properties of CS-GLA, CS-GLA/TNC-25, and CS-GLA/TNC-50 for the RR120 dye in the aqueous solution were evaluated. CS-GLA/TNC-25 exhibited the best adsorptive property possibly because of the perfect balancing between the surface area and available amine (NH2) groups in the composite formulation. The impact of adsorption key parameters, such as adsorbent dosage (0.01-1.2 g), RR120 dye concentration (30-400 mg/L), solution pH (3-12), and contact time (0-400 min) were explored by batch adsorption mode. The adsorption was well described by the Freundlich model and pseudo-second order kinetic model. The adsorption capacity of CS-GLA/TNC-25 for RR120 dye was 103.1 mg/g at 303K. The adsorption mechanism of RR120 on the CS-GLA/TNC-25 surface can be assigned to various interactions, such as electrostatic attraction, n-π stacking, and H-bonding. Results indicate the potential application of CS-GLA/TNC-25 as environment-friendly biosorbent for removing acid and/or textile dyes, such as RR120, from aqueous environments.
The use of chemical modification of cellulosic fibre is applied in order to increase the hydrophobicity, hence improving the compatibility between the fibre and matrix bonding. In this study, the effect of propionic anhydride modification of kenaf fibre was investigated to determine the role of bionanocarbon from oil palm shell agricultural wastes in the improvement of the functional properties of bionanocomposites. The vinyl esters reinforced with unmodified and propionic anhydride modified kenaf fibres bio nanocomposites were prepared using 0, 1, 3, 5 wt% of bio-nanocarbon. Characterisation of the fabricated bionanocomposite was carried out using FESEM, TEM, FT-IR and TGA to investigate the morphological analysis, surface properties, functional and thermal analyses, respectively. Mechanical performance of bionanocomposites was evaluated according to standard methods. The chemical modification of cellulosic fibre with the incorporation of bionanocarbon in the matrix exhibited high enhancement of the tensile, flexural, and impact strengths, for approximately 63.91%, 49.61% and 54.82%, respectively. The morphological, structural and functional analyses revealed that better compatibility of the modified fibre-matrix interaction was achieved at 3% bionanocarbon loading, which indicated improved properties of the bionanocomposite. The nanocomposites exhibited high degradation temperature which signified good thermal stability properties. The improved properties of the bionanocomposite were attributed to the effect of the surface modification and bionanocarbon enhancement of the fibre-matrix networks.
In recent years, nanotechnology in merging with biotechnology has been employed in the area of cancer management to overcome the challenges of chemopreventive strategies in order to gain promising results. Since most biological processes occur in nano scale, nanoparticles can act as carriers of certain drugs or agents to deliver it to specific cells or targets. In this study, we intercalated Epigallocatechin-3-Gallate (EGCG), the most abundant polyphenol in green tea, into Ca/Al-NO3 Layered double hydroxide (LDH) nanoparticles, and evaluated its efficacy compared to EGCG alone on PC3 cell line. The EGCG loaded LDH nanohybrids were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM) and nanosizer analyses. The anticancer activity of the EGCG-loaded LDH was investigated in prostate cancer cell line (PC3) while the release behavior of EGCG from LDH was observed at pH 7.45 and 4.25. Besides enhancing of apoptotic activity of EGCG, the results showed that intercalation of EGCG into LDH can improve the anti- tumor activity of EGCG over 5-fold dose advantages in in-vitro system. Subsequently, the in-vitro release data showed that EGCG-loaded LDH had longer release duration compared to physical mixture, and the mechanism of diffusion through the particle was rate-limiting step. Acidic attack was responsible for faster release of EGCG molecules from LDH at pH of 4.25 compared to pH of 7.4. The results showed that Ca/Al-LDH nanoparticles could be considered as an effective inorganic host matrix for the delivery of EGCG to PC3 cells with controlled release properties.
Novel bio-based polyurethane (PU) nanocomposites composed of cellulose nanofiller extracted from the rachis of date palm tree and polycaprolactone (PCL) diol based PU were prepared by casting/evaporation. Two types of nanofiber were used: cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs). The mechanical and thermal properties of the nanocomposite films were studied by DMA, DSC, and tensile tests and the morphology was investigated by SEM. Bionanocomposites presented good mechanical properties in comparison to neat PU. While comparing both nanofillers, the improvement in mechanical and thermal properties was more pronounced for the nanocomposites based on CNF which could be explained, not only by the higher aspect ratio of CNF, but also by their better dispersion in the PU matrix. Calculation of the solubility parameters of the nanofiller surface polymers and of the PU segments portend a better interfacial adhesion for CNF based nanocomposites compared to CNC.
The current research discusses the development of poly (lactic acid) (PLA) and poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) reinforced nanocrystalline cellulose bionanocomposites. The nanocrystalline cellulose was derived from waste oil palm empty fruit bunch fiber by acid hydrolysis process. The resulting nanocrystalline cellulose suspension was then surface functionalized by TEMPO-mediated oxidation and solvent exchange process. Furthermore, the PLA/PHBV/nanocrystalline cellulose bionanocomposites were produced by solvent casting method. The effect of the addition of nanocrystalline cellulose on structural, morphology, mechanical and barrier properties of bionanocomposites was investigated. The results revealed that the developed bionanocomposites showed improved mechanical properties and decrease in oxygen permeability rate. Therefore, the developed bio-based composite incorporated with an optimal composition of nanocrystalline cellulose exhibits properties as compared to the polymer blend.
A very simple and low-cost procedure has been adopted to synthesize efficient copper (Cu), silver (Ag) and copper-silver (Cu-Ag) mixed nanoparticles on the surface of pure cellulose acetate (CA) and cellulose acetate-copper oxide nanocomposite (CA-CuO). All nanoparticles loaded onto CA and CA-CuO presented excellent catalytic ability, but Cu-Ag nanoparticles loaded onto CA-CuO (Cu0-Ag0/CA-CuO) exhibited outstanding catalytic efficiency to convert 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of NaBH4. Additionally, the Cu0-Ag0/CA-CuO can be easily recovered by removing the sheet from the reaction media, and can be recycled several times, maintaining high catalytic ability for four cycles.
Bionanocomposite films based on regenerated cellulose (RC) and incorporated with zeolite at different concentrations were fabricated by dissolving cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid using a simple green method. The interactions between the zeolite and the cellulose matrix were confirmed by Fourier transform infrared spectra. Mechanical properties of the nanocomposite films significantly improved as compared with the pure regenerated cellulose film, without the loss of extensibility. Zeolite incorporation enhanced the thermal stability and char yield of the nanocomposites. The scanning electron microscopy and transmission electron microscopy showed that zeolite was uniformly dispersed in the regenerated cellulose matrix. In vitro cytotoxicity test demonstrated that both RC and RC/zeolite nanocomposite films are cytocompatible. These results indicate that the prepared nanocomposites have potential applications in biodegradable packaging, membranes and biomedical areas.
The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3wt.% and 6wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900°C for 1h. The GNP (0.5-2wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15h. The sintering process was performed using hot isostatic pressing at processing conditions of 1150°C and 160MPa with a 1-h holding time. The results indicated that the phase compositions and structural features of the products were noticeably affected by the Ni and GNPs. The mechanical properties of Ni6 and 1.5Ni6 were increased by 55% and 75% in hardness, 59% and 163% in fracture toughness and 120% and 85% in elastic modulus compared with monolithic HA, respectively. The in-vitro biological behavior was investigated using h-FOB osteoblast cells in 1, 3 and 5days of culture. Based on the osteoblast results, the cytotoxicity of the products was indeed affected by the Ni doping. In addition, the effect of GNPs on the growth and proliferation of osteoblast cells was investigated in Ni6 composites containing different ratios of GNPs, where 1.5wt.% was the optimum value.
This work aims to shed light in the fabrication of poly(3-hydroxybutyrate-co-44%-4-hydroxybutyrate)[P(3HB-co-44%4HB)]/chitosan-based silver nanocomposite material using different contents of silver nanoparticle (SNP); 1-9 wt%. Two approaches were applied in the fabrication; namely solvent casting and chemical crosslinking via glutaraldehyde (GA). A detailed characterization was conducted in order to yield information regarding the nanocomposite material. X-ray diffraction analysis exhibited the nature of the three components that exist in the nanocomposite films: P(3HB-co-4HB), chitosan, and SNP. In term of mechanical properties, tensile strength, and elongation at break were significantly improved up to 125% and 22%, respectively with the impregnation of the SNP. The melting temperature of the nanocomposite materials was increased whereas their thermal stability was slightly changed. Scanning electron microscopy images revealed that incorporation of 9 wt% of SNP caused agglomeration but the surface roughness of the material was significantly improved with the loading. Staphylococcus aureus and Escherichia coli were completely inhibited by the nanocomposite films with 7 and 9 wt% of SNP, respectively. On the other hand, degradation of the nanocomposite materials outweighed the degradation of the pure copolymer. These bioactive and biodegradable materials stand a good chance to serve the vast need of biomedical applications namely management and care of wound as wound dressing.
This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO2. Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO2 nanoparticles onto functionalized-CNTs loaded TiO2, with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium.
In the present study, a nanocomposite of f-MWCNTs-chitosan-Co was prepared by the immobilization of Co(II) on f-MWCNTs-chitosan by a self-assembly method and used for the quantitative determination of paracetamol (PR). The composite was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). The electroactivity of cobalt immobilized on f-MWCNTs-chitosan was assessed during the electro-oxidation of paracetamol. The prepared GCE modified f-MWCNTs/CTS-Co showed strong electrocatalytic activity towards the oxidation of PR. The electrochemical performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under favorable experimental conditions, differential pulse voltammetry showed a linear dynamic range between 0.1 and 400 μmol L-1 with a detection limit of 0.01 μmol L-1 for the PR solution. The fabricated sensor exhibited significant selectivity towards PR detection. The fabricated sensor was successfully applied for the determination of PR in commercial tablets and human serum sample.
Alginate-based bipolymeric-nanobioceramic composite matrices for sustained drug release were developed through incorporation of nano-hydroxyapatite [nHAp] powders within ionotropically-gelled calcium ion-induced alginate-poly (vinyl pyrrolidone) blends polymeric systems. nHAp powders were synthesized by precipitation technique using calcium hydroxide [Ca(OH)2] and orthophosphoric acid [H3PO4] as raw materials. The average particle size of these was synthesized. nHAp powders was found as 19.04 nm and used to prepare nHAp-alginate-PVP beads containing DS. These beads exhibited drug entrapment efficiency (%) of 65.82±1.88 to 94.45±3.72% and average bead sizes of 0.98±0.07 to 1.23±0.15 mm. These beads were characterized by scanning electron microscopy (SEM) and Fourier transform-infra red (FTIR) spectroscopy analyses. Various nHAp-alginate-PVP beads containing DS exhibited prolonged sustained drug release and followed the Koresmeyer-Peppas model of drug release (R2=0.9908-0.9978) with non-Fickian release (anomalous transport) mechanism (n=0.73-0.84) for drug release over 8 h.
This article explains recent advances in the synthesis and characterization of novel titanium-based nanocomposite materials. Currently, it is a pressing concern to develop innovative skills for the fabrication of hybrid nanomaterials under varying experimental conditions. This review generally focuses on the adsorption behavior of nanocomposites for the exclusion of organic and inorganic pollutants from industrial effluents and their significant applications in various fields. The assessment of recently published articles on the conjugation of organic polymers with titanium has revealed that these materials may be a new means of managing aquatic pollution. These nanocomposite materials not only create alternative methods for designing novel materials, but also develop innovative industrial applications. In the future, titanium-based hybrid nanomaterials are expected to open new approaches for demonstrating their outstanding applications in diverse fields.
A new layered organic-inorganic nanocomposite material with an anti-parkinsonian active compound, L-3-(3,4-dihydroxyphenyl) alanine (levodopa), intercalated into the inorganic interlayers of a Zn/Al-layered double hydroxide (LDH) was synthesized using a direct coprecipitation method. The resulting nanocomposite was composed of the organic moiety, levodopa, sandwiched between Zn/Al-LDH inorganic interlayers. The basal spacing of the resulting nano-composite was 10.9 Å. The estimated loading of levodopa in the nanocomposite was approximately 16% (w/w). A Fourier transform infrared study showed that the absorption bands of the nanocomposite were characteristic of both levodopa and Zn/Al-LDH, which further confirmed intercalation, and that the intercalated organic moiety in the nanocomposite was more thermally stable than free levodopa. The resulting nanocomposite showed sustained-release properties, so can be used in a controlled-release formulation. Cytotoxicity analysis using an MTT assay also showed increased cell viability of 3T3 cells exposed to the newly synthesized nanocomposite compared with those exposed to pure levodopa after 72 hours of exposure.
Graphene-based adsorbents have attracted wide interests as effective adsorbents for heavy metals removal from the environment. Due to their excellent electrical, mechanical, optical and transport properties, graphene and its derivatives such as graphene oxide (GO) have found various applications. However, in many applications, surface modification is necessary as pristine graphene/GO may be ineffective in some specific applications such as adsorption of heavy metal ions. Consequently, the modification of graphene/GO using various metals and non-metals is an ongoing research effort in the carbon-material realm. The use of organic materials represents an economical and environmentally friendly approach in modifying GO for environmental applications such as heavy metal adsorption. This review discusses the applications of organo-functionalized GO composites for the adsorption of heavy metals. The aspects reviewed include the commonly used organic materials for modifying GO, the performance of the modified composites in heavy metals adsorption, effects of operational parameters, adsorption mechanisms and kinetic, as well as the stability of the adsorbents. Despite the significant research efforts on GO modification, many aspects such as the interaction between the functional groups and the heavy metal ions, and the quantitative effect of the functional groups are yet to be fully understood. The review, therefore, offers some perspectives on the future research needs.
The aim of this study was to investigate the effects of temperature change and immersion in two common beverages on the mechanical and tribological properties for three different types of dental restorative materials. Thermocycling procedure was performed for simulating temperature changes in oral conditions. Black tea and soft drink were considered for beverages. Universal composite, universal nanohybrid composite and universal nanofilled composite, were used as dental materials. The nanoindentation and nanoscratch experiments were utilized to determine the elastic modulus, hardness, plasticity index and wear resistance of the test specimens. The results showed that thermocycling and immersion in each beverage had different effects on the tested dental materials. The mechanical and tribological properties of nanohybrid composite and nanocomposite were less sensitive to temperature change and to immersion in beverages in comparison with those of the conventional dental composite.