Nano Biocomposites Research Articles

Tetrabutylphosphonium-salicyl-imine-chitosan metallo-Schiff bases:Supramolecular architectures as multifunctional pharmacological materials.

The current work provides a simple synthetic route for the preparation of poly-(phosphonium-salicyl)-grafted chitosan Schiff bases (PPCSB), its M(II) complexes (M = Cu or Pd) and silver nanobiocomposites (NBCs). The ex-situ protocol was used for preparation of nanosilver (AgNPs) using NaBH4 as a reducing agent then capped either by PPCSB or Pd(II)PPCSB to fabricate NBCs {AgNPs@PPCSB, AgNPs@Pd(II)PPCSB}. Structural, morphological and physicochemical characterizations of the new architectures were examined based upon diverse spectral and microscopic techniques. The antibacterial properties of new compoundswas investigated against gram positive (S. aureus, B.subtilis) and gram negative (E. coli, P. aeruginosa) bacterial strains. Unexpectedly, the M(II)PPCSB complexes were found to be more active against all tested bacterial strains than NBCs (AgNPs@PPCSB, AgNPs@Pd(II)PPCSB). Meanwhile, as revealed from ZOI values, the Cu(II)PPCSB is the most potent bactericidal agent against all tested bacterial strains except E. coli species which is more affected by Pd(II)PPCSB

Studies on the controlled release of drugs from magnetic nanobiocomposites

Magnetic nanocomposites are a class of smart materials that have attracted recent interest as drug delivery systems or as medical implants. In this study, meltable nanobiocomposites (NBC) composed of biocompatible dextran fatty acid ester and magnetic nanoparticles (MNPs) melting close to human body temperature were prepared and loaded with Rhodamine B (RhB) or green fluorescent protein (GFP) as model drugs to evaluate their potential use as drug delivery system. The release of the model drugs from the magnetic NBC investigated under the influence of a high frequent alternating magnetic field (AMF, 20 kA/m at 400 kHz) showed that on-demand release is realized applying the external AMF. The NBC showed a long-term stability (28 d) of the incorporated iron oxide particles after incubation in artificial body fluids. This work reveals the potential of the NBC as a drug carrier.

Preparation and antibacterial properties of nano biocomposite Poly(ε-caprolactone)-SiO2 films with nanosilver

Two different silica samples with different particle size distributions (Silica-I: 40–63 μm, Silica-II: 90% below <55 μm) were utilized after the nano silver (5–30 nm) coating process by poly(dimethylsiloxane) in acetone. The prepared nano Ag-silica powders were melt-mixed into poly(e-caprolactone) (PCL) and the mixture was roll-milled to produce the nano biocomposite films containing 10%, 20% and 40% nano Ag-silica. The antibacterial activity of the composite films against E. coli was evaluated. For the PCL films with 40% Ag-silica (0.08–0.12% nanosilver), 100% reduction of the bacterial contamination was observed. The nanosilver coated silica particles could find applications in antibacterial nano biocomposites.

In vivo diabetic wound healing potential of nanobiocomposites containing bamboo cellulose nanocrystals impregnated with silver nanoparticles

In diabetes, hyperglycemic state immensely hinders the wound healing. Here, nanobiocomposites (NCs) developed by impregnation of in situ prepared silver nanoparticles in the matrix of bamboo cellulose nanocrystals were investigated for their ability to hasten the progress of healing events in streptozotocin induced diabetic mice model. Wounds treated with topically applied NCs (hydrogels) showed full recovery (98–100%) within 18days post wounding in contrast to the various control groups where incomplete healing (88–92%) was noticed. Biochemical estimations documented a marked decrease in the levels of pro-inflammatory cytokines IL-6 and TNF-α leading to decreased inflammation in NCs treated mice. Significantly increased expression of collagen and growth factors (FGF, PDGF, VEGF) upon NCs treatment resulted in improved re-epithelialization, vasculogenesis and collagen deposition as compared to control groups. Hence, developed nanobiocomposites showcased potential to serve as highly effective and biocompatible wound dressings for diabetic patients.

Water-Soluble Naked Gold Nanoclusters Are Not Luminescent.

Here, the synthesis of water-dispersible naked gold nanoclusters (AuNCnaked ) is reported by a simple reduction of HAuCl4 with NaOH at room temperature, and it is shown that they are non-luminescent. They are then easily passivated with different thiols and adenosine monophosphate, leading to luminescent NCs. This is an important finding because the photoluminescence of the passivated NCs can now be clearly attributed to the ligand-AuNC surface interaction. These results are also highly relevant from the point of view of the preparation of luminescent NCs from the same NC batch. This strategy can be valuable for the preparation of a broad range of nano(bio)composites.

In situ functionalized nanobiocomposites dressings of bamboo cellulose nanocrystals and silver nanoparticles for accelerated wound healing

An innovative approach was adopted where in situ synthesized silver nanoparticles (AgNPs) from leaf extract mediated reduction of AgNO3 were simultaneously impregnated into the matrix of cellulose nanocrystals (CNCs) isolated from Dendrocalamus hamiltonii and Bambusa bambos leaves, for formation of nanobiocomposites (NCs) in film and ointment forms. Here, use of plant CNCs was chosen as an alternate to bacterial cellulose for wound dressings. NCs possessing water absorption capacity and strong antibacterial activity showed synergistic effect on in vivo skin wound healing and documented faster and significant wound closure in treated mice. NCs exhibited lesser inflammation and early vasculogenesis at day 3 coupled with increased fibroblasts and collagen content at day 8 leading to faster neo-epithelization by day 14. Highly effective, biocompatible, and easy to apply NCs wound dressings (ointment and films) containing low amounts of Ag (0.05±0.01wt%) are potential candidates for effective skin repair.

Effect of reinforced Al2O3 nanoparticles on collagen nanobiocomposite from chrome-containing leather waste for biomedical applications

The present study aims at developing nanobiocomposite from collagen extracted from solid biowaste, chrome-containing leather waste having aluminium oxide nanoparticles as reinforcement for value-added products. The extracted collagen was confirmed using sodium dodecyl sulphate-poly(acrylamide) gel electrophoresis technique, while Fourier-transform infrared spectroscopy and scanning electron microscopy were used to study the physicochemical and morphological properties of the prepared composites. Enhanced thermal stability and increase in denaturation temperature from 39 to 43 °C with the increase in aluminium oxide content from 2 to 10 % in the composites were confirmed by differential scanning calorimetry and thermogravimetric analyses. Improved mechanical properties such as tensile, tear and flexural strength for the nanobiocomposites (NBCs) were also obtained. Moreover, decrease in water uptake from 475 to 285 % with the increase in aluminium oxide nanoparticles is attributed to the reduced porosity and their weak interaction with collagen that reduces the hydrophilicity of the NBCs. The above results indicate that the collagen-based NBCs present a simple, clean and easy route for effective recycling and recovery of biowaste that could find use in hip prosthesis and has the potential to be used in other biomedical applications.

Spray-Dried Multiscale Nano-biocomposites Containing Living Cells.

Three-dimensional encapsulation of cells within nanostructured silica gels or matrices enables applications as diverse as biosensors, microbial fuel cells, artificial organs, and vaccines; it also allows the study of individual cell behaviors. Recent progress has improved the performance and flexibility of cellular encapsulation, yet there remains a need for robust scalable processes. Here, we report a spray-drying process enabling the large-scale production of functional nano-biocomposites (NBCs) containing living cells within ordered 3D lipid-silica nanostructures. The spray-drying process is demonstrated to work with multiple cell types and results in dry powders exhibiting a unique combination of properties including highly ordered 3D nanostructure, extended lipid fluidity, tunable macromorphologies and aerodynamic diameters, and unexpectedly high physical strength. Nanoindentation of the encasing nanostructure revealed a Young's modulus and hardness of 13 and 1.4 GPa, respectively. We hypothesized this high strength would prevent cell growth and force bacteria into viable but not culturable (VBNC) states. In concordance with the VBNC state, cellular ATP levels remained elevated even over eight months. However, their ability to undergo resuscitation and enter growth phase greatly decreased with time in the VBNC state. A quantitative method of determining resuscitation frequencies was developed and showed that, after 36 weeks in a NBC-induced VBNC, less than 1 in 10,000 cells underwent resuscitation. The NBC platform production of large quantities of VBNC cells is of interest for research in bacterial persistence and screening of drugs targeting such cells. NBCs may also enable long-term preservation of living cells for applications in cell-based sensing and the packaging and delivery of live-cell vaccines.

Synthesis and application of polypyrrole/carrageenan nano-bio composite as a cathode catalyst in microbial fuel cells

A novel nano-bio composite polypyrrole (PPy)/kappa-carrageenan(KC) was fabricated and characterized for application as a cathode catalyst in a microbial fuel cell (MFC). High resolution SEM and TEM verified the bud-like shape and uniform distribution of the PPy in the KC matrix. X-ray diffraction (XRD) has approved the amorphous structure of the PPy/KC as well. The PPy/KC nano-bio composites were then studied as an electrode material, due to their oxygen reduction reaction (ORR) ability as the cathode catalyst in the MFC and the results were compared with platinum (Pt) as the most common cathode catalyst. The produced power density of the PPy/KC was 72.1mW/m2 while it was 46.8mW/m2 and 28.8mW/m2 for KC and PPy individually. The efficiency of the PPy/KC electrode system is slightly lower than a Pt electrode (79.9mW/m2) but due to the high cost of Pt electrodes, the PPy/KC electrode system has potential to be an alternative electrode system for MFCs.

Design, Characterization and Evaluation of Metallic Nano Biocomposites of Neomycin

Neomycin is formulated into nanoparticles in order to increase the therapeutic efficacy, decrease the dose of drug and to decrease the topical dose related toxic effects. The present study was aimed at the preparation of zinc nanoparticles (ZN), chitosan nanoparticles (CN), zinc neomycin nanoparticles (ZNN) and zinc chitosan neomycin nanoparticles (ZCNN) in order to compare their antibacterial activity. Nanoparticles were prepared by subjecting the nano suspension containing the specified ingredients to stirring at 40oC for 4-5 h. The prepared nanoparticles were evaluated for particle size and surface morphology by Transmission Electron Microscopy (TEM), mean particle size and particle size distribution by DLS, percentage yield, loading efficiency, in vitro drug release by diffusion technique and agar cup plate method. TEM microphotographs and zeta sizer analysis revealed that the prepared nanoparticles were in the nanometric range, the particle size and particle size range of ZCNN was less compared to ZNN indicated more surface area of ZCNN. Among all the nanoparticles prepared, percentage yield, loading efficiency, in vitro drug release and zone of inhibition was found to be more for ZCNN. Thus, the results suggested that ZCNN act as promising drug delivery systems with better in vitro characteristics compared to other nanoparticles with increased therapeutic activity of neomycin.

Isolation and characterization of microcrystalline cellulose from oil palm biomass residue

In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen–ozone–hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed.

Graphene sulphonic acid/chitosan nano biocomposites with tunable mechanical and conductivity properties

Nanocomposites of chitosan are produced using graphene sulphonic acid (SG) at five different compositions and are designated as SG0.5, SG0.75, SG1, SG3 and SG5; the numbers indicate weight percent of SG. The TEM & AFM micrographs indicate that the SG sheets are in exfoliated state. The thermal stability and the storage modulus of the composites increase with increasing SG concentration showing a maximum increase (202%) for SG5 sample. The stresses at break and Young’s modulus have increased with increasing SG content. SG5 shows the highest increase of both tensile strength and Young’s modulus of 290 ± 7% and 200 ± 7%, respectively. Analysis of the Young’s modulus data suggests that SG sheets are randomly distributed and at ≥1 wt% concentration they are unidirectionally oriented parallel to the film. The system exhibits percolation threshold of 0.49 wt% SG and it attains maximum conductivity of 0.13 S m−1 at 1.6 wt% SG.

Comparative study of hydroxyapatite/gelatin composites reinforced with bio-inert ceramic particles

Recently, nano bio-composites have emerged as an efficient strategy to upgrade the structural and functional properties of synthetic bone grafts. Bioinert ceramics have attracted wide attention because of their biocompatibility. Novel composites of nano-hydroxyapatite/GEL with incorporation of bioinert ceramics like Al2O3, TiO2 and ZrO2 for different composites as a reinforcing phase to increase its mechanical properties was prepared. The nHAp with the size of 10–50nm in diameter and 50–100nm in length was uniformly distributed into GEL matrix to form the composite. It was found that the composite with a high ceramic content has good homogeneity and mechanical strength, which are close to the cancellous bone. An interconnected porous material with porosity of at least 74% was achieved by phase inversion method. The formation reaction of the nHAp/GEL/bioinert ceramic nanocomposite was then investigated via FT-IR, XRD, TG/DTA and SEM. The organic–inorganic interaction between HAp nano crystallites and GEL molecules were confirmed from FT-IR and TG/DTA. The compressive strength of bioinert ceramic reinforced nanocomposites scaffolds could high up to 13.15MPa while those of nHAp/GEL were 4.87MPa. The nano indentation technique was used to find nano hardness and fracture toughness was evaluated by Vickers indentation.

Hydroxyapatite - starch nano biocomposites synthesis and characterization

Bone like hydroxyapatite (nHAp) was synthesized via an in situ biomimetic process in presence of wheat starch. The effect of polymer concentration alteration on the final structure of nHAp was investigated. Formation of the nHAp at room temperature was confirmed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Size and morphology of the nHAp samples were characterized using scanning and transmission electron microscopy (SEM and TEM). Starch as a template agent has influence on shape of the HAp precipitated in its aqueous solution. It leads to formation of rode like nHAp which is similar to this inorganic component in natural bone.

Studies on aliphatic -aromatic random copolyester- based nano-biocomposite materials

Aliphatic-aromatic biodegradable random copolyester, poly (butylene succinate-co-butylene isophthalate) PBSI was synthesised by a two step direct melt polycondensation method. This copolyester was characterised by solubility, viscosity measurements, IR, 1 H NMR, 13C NMR and thermal studies. But, to be a real alternative to classical synthetic polymers and find applications, biodegradable polymer properties have to be enhanced. Synthesis of nano–biocomposites, which are obtained by incorporation of nanofillers into a biomatrix, is an interesting way to achieve the polymers with characteristic property. In present study, the nano- biocomposites were synthesised by dispersing different weight percentage (1, 3 and 5 %) of organo modified montmorillonite clay (OMMT) into the biodegradable polyester matrix by solvent intercalation method. The structural characterisation and thermal analysis have been carried out to understand better the relationship between the nanofillers structuring and the properties of nano-biocomposites. The X-ray diffraction patterns obtained for the systems confirmed the nanodispersion of OMMT-clay in the polyester networks. The results show that the clay incorporation and the obtained structures enhanced the thermal properties of PBSI, and thus may increase the applicability of this biodegradable polymer in different fields. Keywords: Nano- biocomposites, biodegradable, montmorillonite clay, aliphatic-aromatic random copolyesters.

Preliminary investigation of bioactivity of nano biocomposite

Bioactive biomaterials can form a bone-like apatite layer on their surfaces in the body, which is critical to establishing bone bonding between bioactive materials and living tissue. At present study, the bone-like apatite formation in vitro and vivo on the surface of the nano apatite/polyamide composite was studied, and the bioactive composites implanted into the femora of rabbits were also investigated. The results revealed that the bone-like apatite containing carbonate can form on the surface of the biocomposite both in SBF and dorsal muscle of rabbits, and the composite would form directly combination with the natural bone without fibrous capsule tissue between implant and host bone tissue. All of these indicated that the nano biocomposites have excellent bioactivity and can be used for bone replacement.