Polylactic acid/multi walled carbon nanotubes (PLA/MWCNT) nanocomposite for 3D printing of medical devices

In recent years, the composite nanomaterials area has had a great development impact in health sciences. Biomaterials depict as one of the most promising since they are compatible with additive manufacturing (AM) techniques. It is also possible to use them to mold specific medical parts. Composite nanomaterials have shown good biocompatibility and low toxicity to have benefits equal to or greater than metals (i.e., Co-Cr alloy). The purpose of this study is to develop a nanocomposite biomaterial (PLA/MWCNTf) from Polylactic Acid (PLA) and functionalized Multi Walled Carbon Nanotubes (MWCNTf) to evidence its potential application in 3D printing of orthopedic fixation devices. PLA/MWCNTf nanocomposite was prepared by solution blending technique, incorporating a proportion of 0.5 wt% of MWCNTf to the PLA matrix. TGA analysis of the PLA/MWCNTf was used to determine the thermal stability, a slight increase was found compared to the PLA. FTIR spectroscopy confirmed the presence of carboxylic acid groups in the MWCNTf which improves good incorporation of the nanotubes in the PLA matrix. Additionally, Raman spectroscopy, SEM, and AFM micrographs were used to verify MWCNTf reached the PLA surface homogeneously. Additive manufacturing preparation was done by extrusion molding of PLA/MWCNTf as well as its 3D printing.

The composition of edible oils modifies β-sitosterol/γ-oryzanol oleogels part II: Addition of selected minor oil components

The first part of this study showed that the triglyceride composition of purified oils has little impact on sterol/sterol ester oleogels. Hence, changes in the gels’ properties observed in previous studies must arise from minor polar components, particularly by changing the interactions within the fibrillar network. Selected molecules (oleic acid, tocopheryl acetate, monoglycerides, and water) were added to three purified oils to unravel the individual contributions introduced by different functional groups. While all additives retarded the molecular self-assembly of sitosterol with oryzanol, distinct effects were found for gel hardness, transition temperatures and enthalpies, strain sweep responses, and microstructure. It was discovered that the maximum storage modulus in the linear viscoelastic region does not necessarily relate to the gels’ compression firmness. In samples comprising oleic acid and tocopheryl acetate, discrete interaction mechanisms with the scaffolding elements were suggested since results between the two additives developed differently and were dose-dependent. A network supporting effect was suggested at low concentrations, in line with previous results for oils comprising low levels of thermal deterioration products. The microstructure of oleogels was considerably modified with additives. Unfortunately, effects are difficult to quantify due to the packed surface observed in AFM micrographs.

Excellent Photocatalytic Degradation of Indigo Dye using Low Cost Chemical Route Grown Highly Luminescent SnO2 Decorated Polystyrene Nanocomposites

Irrational use of dye is a challenge for our environment specifically for clean water. Highly luminescent SnO2 decorated Polystyrene nanocomposites developed as an effective solution for it. The low cost chemical synthesis of highly luminescent tin oxide decorated Polystyrene (SnO2-PS) polymer nanocomposites using recyclable expended polystyrene waste has been reported. Sol gel grown tin oxide nanoparticles, thoroughly dissolved in dissolved in toluene were used with recyclable expended polystyrene waste. The composites were grown either on glass substrates or developed as flexible self sustaining layers and characterized by optical, structural & morphological characterizations. X ray diffractograms of SnO2-PS polymer nanocomposites exhibit crystalline behavior with tetragonal structure of SnO2. Accumulation of SnO2 particles on the surface with increasing concentration, in the form of spherical structures is observed in AFM micrographs. Hollow vertical chain like growth is also observed. Absorption edge shift towards higher wavelength results in decrease in band gap with increasing concentration. The Photoluminescence (PL) spectra for higher SnO2 shows a significant peak peaks in visible spectra at about 425 nm. SnO2 decorated Polystyrene nanocomposites synthesized using recyclable expended polystyrene waste opens a new scope in flexible optoelectronic applications with visible region photoluminescence.

Surface treated cotton fabric with stain repellent property for the use in aircraft upholstery

Nanotechnology modifications play a major role in textile industry due to extraordinary properties exhibit in fabrics due to nanomaterials. It offers different functionalities namely self-cleaning, wrinkle resistance, flame retardancy, protection from UV radiations or antibacterial property. Further, it is important to maintain cleanliness in aircraft upholstery always but the airliners have to bear a considerable amount of money to clean up the aircraft upholstery. Interestingly, nanotechnology can provide stain repellence property for fabrics in aircraft upholstery. This study covers a method of developing a stain repellent fabric which was stable even after 25 standard laundering conditions. In this study nanotechnology was used to modify a cotton fabric with stain repellant property. After nanotechnology modification, the surface wettability of the treated fabrics was characterized by static water contact angle measurements before and after 25 washes carried out under standard laundering conditions. Similar testings were carried out for the untreated fabric samples. The static water contact angle for the treated fabric was 161° with the recovery of 97.5% after 25 washing cycles. SEM and AFM micrographs were used to analyze the coatings. Further, the stability of hydrophobicity in the modified cotton fabric after 25 washes was also tested for tea, coffee, and water solutions which are vulnerable stain types in aircraft upholstery. It clearly proved that the modified cotton fabric even after 25 washes showed hydrophobicity for tea, coffee, and water. Therefore, it could be concluded that the developed modified cotton fabric can consider to be used as an aircraft upholstery.

Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites

Natural fibres have a high potential as reinforcement of polymer matrices, as they combine a high specific strength and modulus with sustainable production and reasonable prices. Modifying the fibre surface is a common method to increase the adhesion and thereby enhance the mechanical properties of composites. In this study, a novel sustainable surface treatment is presented: the fungal enzyme laccase was utilised with the aim of covalently binding the coupling agent dopamine to flax fibre surfaces. The goal is to improve the interfacial strength towards an epoxy matrix. SEM and AFM micrographs showed that the modification changes the surface morphology, indicating a deposition of dopamine on the surface. Fibre tensile tests, which were performed to check whether the fibre structure was damaged during the treatment, showed that no decrease in tensile strength or modulus occurred. Single fibre pullout tests showed a 30% increase in interfacial shear strength (IFSS) due to the laccase-mediated bonding of the coupling agent dopamine. These results demonstrate that a laccase + dopamine treatment modifies flax fibres sustainably and increases the interfacial strength towards epoxy.

Synthesis and Characterization of CoFe2O4 Nanoparticles Prepared by Sol-Gel Method

Cobalt Ferrite (CoFe2O4) nanoparticles (NPs) were prepared by Sol-Gel precipitation method. Two samples were synthesized and sintered with different sintering temperatures; sample A at 400 °C and sample B at 800 °C for two hours. The prepared samples were characterized by XRD, FTIR, SEM, and AFM, Compressive test and Micro-hardness. The result showed as the sintering temperatures increased, the crystallite size increased from 10.07 nm to 15.14 nm. FTIR spectra showed two strong absorption bands in the range of 800 - 400 cm-1, confirmed formation of spinel ferrites NPs. SEM and AFM micrographs showed that the samples have an approximately spherical shape. The mechanical properties of CoFe2O4 NPs were not widely studied. Therefore, in this work, the mechanical properties (Compressive strength and Micro-hardness) of prepared material studied as an important contribution for researchers to focus on mechanical properties of CoFe2O4 NPs. Where the mechanical result showed that both the compressive strength was increased (from 4.42 to 10.57 N/mm2) and Micro-hardness (from 10.33 to 174.4 N/mm2) with increasing sintering temperature.

Evaluation of Antioxidant and Cytotoxic Effects of Liposomes Containing Pineapple Fruit Extract on Melanoma Skin Cancer (A375 Cell Line)

Introduction: The use of The use of nanoparticles containing antioxidant and cytotoxic plant compounds can have a special place in the treatment of melanoma. The aim of this study was to evaluate the antioxidant and cytotoxic effects of pineapple fruit extract on skin cancer. Methods: In the present experimental study, liposomal vesicles were prepared using cholesterol, soy phosphatidylcholine, and polyethylene glycol, and pineapple fruit extract was loaded in liposomes. Physicochemical characteristics were evaluated using zeta sizer, FTIR and AFM. Finally, the toxicity of different concentrations of extract and liposome-containing extract was evaluated in A-375 melanoma cell line using MTT assay. DPPH test was used to evaluate the antioxidant properties of the extract and liposomes containing extract. Statistical analysis was performed using Excel and SPSS (Ver 22) software and Duncan and Student's T-tests were used for statistical conclusion. Results: According to this study showed the encapsulation efficiency of pineapple extract containing liposome, liposome size and its surface charge were 40%, 89.9 nm and -8.8 mV, respectively. FTIR analysis and AFM micrographs also confirm that there is no interaction of the extract with its nanosystem, the spherical morphology of the liposomes and its appropriate distribution and dispersion. The toxicity level of pineapple extract is higher when had been encapsulated rather than the non-encapsulated extract on the A-375 cell line. Conclusion: Pineapple fruit extract has cytotoxic effects on A-375 cell line and the present liposomal nanocarrier can be a suitable carrier for the delivery of the extract and inhibit the growth and proliferation of these cells.

Structure, Optical and Morphological Investigations of Nanostructures in Doped SNO2 Thin Films

Nanostructured Tin oxide and Indium (In) doped SnO2 were prepared by low cost and easy to manufacture method, which is a spray pyrolysis technique (SPT). Film transmittance was noticed to decrease from 67% to 56% (at 800 nm) on doping. XRD patterns revealed that tin oxide and 1% or 3% In:SnO2 thin films are polycrystalline and preferred orientation is 113. AFM micrographs prove that the spherical shape grains are uniformly distributed with average grain size of about 88 nm and root-mean-square (rms) roughness was about 3.5 nm. It can be concluded that the deposited samples are good candidates for use in solar cells applications.

LOCAL PARAMETERS OF THE SURFACE ROUGHNESS OF ELECTROCHEMICALLY DEALLOYED Ag-Pd ALLOYS

Local characteristics of surface roughness of the polycrystalline Ag-Pd solid solutions (4 and 8 at. % Pd) which underwent potentiostatic electrochemical dealloying in an acidic nitrate aqueous solution were determined by scanning electron and atomic force microscopy. A qualitative analysis of the SEM and AFM micrographs demonstrated substantial morphological roughening of the surface of Ag-Pd alloys. This results from the formation of hollows and cracks caused by selective leaching of electronegative silver and recrystallization of electropositive palladium into its highly-developed phase. A quantitative analysis of the AFM-data allowed us to determine the numerical values of the main local roughness characteristics of anodically modified alloys. The negative value of the coefficient of surface asymmetry indicates the formation of deep cavities during the dealloying process. The recorded mean roughness generally depends on the AFM-scanning zone, but it stabilizes if the scan zone exceeds several tens of micrometers. The roughness of dealloyed Ag-Pd systems is of micro- and nano-size and increases with anodic potential and electric charge of the electrochemical modification of both studied Ag4Pd and Ag8Pd alloys. This effect can be accounted for by a significant rise in the anodic dissolution rate of silver from the alloys in the overcritical region of polarization, resulting in the formation of deeper surface defects. An increase in the average height of surface irregularities with modification time conforms to the square root law, confirming the non-stationary mass transfer kinetics of the selective dissolution process. Variation of the anodic potential and electric charge makes it possible to find the optimal conditions for the electrochemical synthesis of electrode Ag-Pd materials with given values of arithmetic mean and root-mean-square roughness. The assumption that harmonic sinusoidal function represents the Ag-Pd surface microprofile proved the linear dependence of the roughness factor on dealloying time.

Bi- tri- and few-layer graphene growth by PLD technique using Ni as catalyst

The objective of the present research work is to optimize the growth conditions of bi- tri- and few-layer graphene using pulsed laser deposition (PLD) technique. The graphene was grown on n-type silicon (1 0 0) at 530 °C. Raman spectroscopy of the grown films revealed that the growth of low defect tri-layer graphene depended upon Ni content and uniformity of the Ni film. The line profile analysis of the AFM micrographs of the films also confirmed the formation of bi- tri- and a few-layer graphene. The deposited uniform Ni film matrix and carbon/Ni thickness ratio are the controlling factors for the growth of bitri- or few- layer graphene using pulsed laser deposition technique.