Vijay K. Rangari

Enhancement of strength and stiffness of Nylon 6 filaments through carbon nanotubes reinforcement

We report a method to fabricate carbon nanotube reinforced Nylon filaments through an extrusion process. In this process, Nylon 6 and multiwalled carbon nanotubes (MWCNT) are first dry mixed and then extruded in the form of continuous filaments by a single screw extrusion method. Thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies have indicated that there is a moderate increase in Tg without a discernible shift in the melting endotherm. Tensile tests on single filaments have demonstrated that Young’s modulus and strength of the nanophased filaments have increased by 220% and 164%, respectively with the addition of only 1wt.% MWCNTs. SEM studies and micromechanics based calculations have shown that the alignment of MWCNTs in the filaments, and high interfacial shear strength between the matrix and the nanotube reinforcement was responsible for such a dramatic improvement in properties.

Enhanced delivery and expression of a nanoencapsulated DNA vaccine vector for respiratory syncytial virus

UNLABELLED This study evaluated the efficiency of chitosan-encapsulated DNA-based respiratory syncytial virus (RSV) vaccine. Antigenic regions of RSV F, M2, and G genes were cloned into the human cytomegalovirus promoter-based constitutive expression vector, resulting in a DNA vaccine vector named DR-FM2G. This vector was used to formulate DNA-chitosan nanoparticles (DCNPs) using a complex coacervation process that yielded an encapsulation efficiency of 94.7%. The DCNP sizes ranged from 80 to 150 nm with uniform size distribution and spherical shape. DNA release was between 50% and 60% when DCNPs were incubated with similar gastrointestinal fluid (pH 2), whereas 21% to 25% of DNA was released from DCNPs in 30 minutes at pH 10. Differential scanning calorimetry showed DCNPs to be more stable than naked DNA or chitosan, offering protection from DNA degradation by nucleases. DCNPs were not toxic to cells when used at concentrations < or =400 microg/mL. Immunohistochemical and real-time polymerase chain reaction results showed a higher level of RSV protein expression in mouse tissues given when DCNPs were injected intravenously as compared with naked DNA. FROM THE CLINICAL EDITOR This study evaluated the efficiency of chitosan-encapsulated DNA-based respiratory syncytial virus (RSV) vaccine, showing a higher level of RSV protein expression in mouse tissues given when DCNPs were injected intravenously as compared with naked DNA.

Sonochemical effect on size reduction of CaCO3 nanoparticles derived from waste eggshells.

A novel combination of mechanochemical and sonochemical techniques was developed to produce high-surface-area, bio-based calcium carbonate (CaCO3) nanoparticles from eggshells. Size reduction of eggshell achieved via mechanochemical and followed by sonochemical method. First, eggshells were cleaned and ground, then ball milled in wet condition using polypropylene glycol for ten hours to produce fine particles. The ball milled eggshell particles were then irradiated with a high intensity ultrasonic horn (Ti-horn, 20 kHz, and 100 W/cm(2)) in the presence of N,N-dimethylformamide (DMF); decahydronaphthalene (Decalin); or tetrahydrofuran (THF). The ultrasonic irradiation times varied from 1 to 5 h. Transmission electron microscopic (TEM) studies showed that the resultant particle shapes and sizes were different from each solvent. The sonochemical effect of DMF is more pronounced and the particles were irregular platelets of ~10 nm. The BET surface area (43.687 m(2)/g) of these nanoparticles is much higher than that of other nanoparticles derived from eggshells.

Gefitinib–cyclodextrin inclusion complexes: physico-chemical characterization and dissolution studies

Background: Gefitinib, an anticancer drug, has an extremely low aqueous solubility, and its oral absorption is limited by its dissolution rate. The solubility and dissolution of gefitinib can be improved by complexation with cyclodextrins (CDs). Methods: Phase solubility studies of gefitinib with hydroxypropyl βCD (HPβCD) and randomly methylated βCD (RMβCD) in n various aqueous systems was conducted to characterize the complexes in the liquid state. The inclusion complexes in the solid state were prepared by freeze-drying method and characterized by X-ray diffractometry (X-RD) and differential scanning calorimetry (DSC). Results: Gefitinib formed stable complexes with HPβCD and RMβCD in distilled water as indicated by the association rate constants (Ks) of 458.9 and 1096.2 M−1 for HPβCD and RMβCD, respectively. The complexation of gefitinib with CDs in pH 4.5 acetate buffer indicated an AN type of phase-solubility diagrams, whereas gefitinib and HPβCD in distilled water in the presence of polymers such as polyvinyl pyrrolidone K-30 (PVP) or hydroxypropyl methylcellulose E3 (HPMC) resulted in AP-type phase-solubility diagrams. The solid-state amorphous complexes (as described by DSC and X-RD) showed substantial increases in the solubility and dissolution rate of gefitinib with both CDs. Further increases in the solubility and dissolution rate of the gefitinib-HPβCD freeze-dried complex were obtained by physically mixing the complex with PVP and HPMC. Conclusion: Gefitinib formed stable inclusion complexes with HPβCD and RMβCD, and the solubility and dissolution rate of the drug was significantly increased.

Molecular cycloencapsulation augments solubility and improves therapeutic index of brominated noscapine in prostate cancer cells

We have previously shown that a novel microtubule-modulating noscapinoid, EM011 (9-Br-Nos), displays potent anticancer activity by inhibition of cellular proliferation and induction of apoptosis in prostate cancer cells and preclinical mice models. However, physicochemical and cellular barriers encumber the development of viable formulations for future clinical translation. To circumvent these limitations, we have synthesized EM011-cyclodextrin inclusion complexes to improve solubility and enhance therapeutic index of EM011. Phase solubility analysis indicated that EM011 formed a 1:1 stoichiometric complex with β-CD and methyl-β-CD, with a stability constant (K(c)) of 2.42 × 10(-3) M and 4.85 × 10(-3) M, respectively. Fourier transform infrared spectroscopy suggested the penetrance of either a O-CH(2) or OCH(3)-C(6)H(4)-OCH(3) moiety of EM011 in the β-CD or methyl-β-CD cavity. In addition, multifarious techniques, namely, differential scanning calorimetry, powder X-ray diffraction, scanning electron microscopy, NMR spectroscopy, and computational studies validated the cage complex of EM011 with β-CD and methyl-β-CD. Moreover, rotating frame overhauser enhancement spectroscopy showed that the H(a) proton of the OCH(3)-C(6)H(4)-OCH(3) moiety was in close proximity with H3 proton of the β-CD or methyl-β-CD cavity. Furthermore, we found that the solubility of EM011 in phosphate buffer saline (pH 7.4) was enhanced by ~11 fold and ~21 fold upon complexation with β-CD and methyl-β-CD, respectively. The enhanced dissolution of the drug CD-complexes in aqueous phase remarkably decreased their IC(50) to 28.5 μM (9-Br-Nos-β-CD) and 12.5 μM (9-Br-Nos-methyl-β-CD) in PC-3 cells compared to free EM011 (~200 μM). This is the first report to demonstrate the novel construction of cylcodextrin-based nanosupramolecular vehicles for enhanced delivery of EM011 that warrants in vivo evaluation for the superior management of prostate cancer.

Cyclodextrin Complexes of Reduced Bromonoscapine in Guar Gum Microspheres Enhance Colonic Drug Delivery

Here, we report improved solubility and enhanced colonic delivery of reduced bromonoscapine (Red-Br-Nos), a cyclic ether brominated analogue of noscapine, upon encapsulation of its cyclodextrin (CD) complexes in bioresponsive guar gum microspheres (GGM). Phase–solubility analysis suggested that Red-Br-Nos complexed with β-CD and methyl-β-CD in a 1:1 stoichiometry, with a stability constant (Kc) of 2.29 × 103 M–1 and 4.27 × 103 M–1. Fourier transforms infrared spectroscopy indicated entrance of an O–CH2 or OCH3–C6H4–OCH3 moiety of Red-Br-Nos in the β-CD or methyl-β-CD cavity. Furthermore, the cage complex of Red-Br-Nos with β-CD and methyl-β-CD was validated by several spectral techniques. Rotating frame Overhauser enhancement spectroscopy revealed that the Ha proton of the OCH3–C6H4–OCH3 moiety was closer to the H5 proton of β-CD and the H3 proton of the methyl-β-CD cavity. The solubility of Red-Br-Nos in phosphate buffer saline (PBS, pH ∼ 7.4) was improved by ∼10.7-fold and ∼21.2-fold when mixed with β-CD and methyl-β-CD, respectively. This increase in solubility led to a favorable decline in the IC50 by ∼2-fold and ∼3-fold for Red-Br-Nos−β-CD-GGM and Red-Br-Nos–methyl-β-CD-GGM formulations respectively, compared to free Red-Br-Nos−β-CD and Red-Br-Nos–methyl-β-CD in human colon HT-29 cells. GGM-bearing drug complex formulations were found to be highly cytotoxic to the HT-29 cell line and further effective with simultaneous continuous release of Red-Br-Nos from microspheres. This is the first study to showing the preparation of drug-complex loaded GGMS for colon delivery of Red-Br-Nos that warrants preclinical assessment for the effective management of colon cancer.

Sonochemical synthesis and characterisation of bio-based hydroxyapatite nanoparticles

Bio-based hydroxyapatite nanoparticles were synthesised via the sonochemical route using phosphoric acid and bio-based calcium carbonate particles extracted from eggshells. Hydroxyapatite is a natural bio ceramic material that contains calcium phosphate group. In this procedure phosphoric acid solution was used as the source of phosphorus and eggshell particles were used as the source of calcium. Eggshells represent a great renewable material for structural applications due to the high content of inorganic calcite. Eggshells were cleaned and ball milled to reduce their sizes to nanoscale. The particles were then heated in a tube furnace to produce calcium oxide particles; these calcium oxide particles were stirred in water for 24 hours at room temperature and formed calcium hydroxide. Phosphoric acid and calcium hydroxide particles were irradiated with high intensity ultrasonic horn for two hours at 10°C in the presence of distilled water. The resultant product was characterised using XRD, TEM and surface area measurements. These results showed that the as-prepared hydroxyapatiteparticles are porous (~20–50 nm), crystalline in nature and thermally stable at least up to 750°C. BET studies showed that as-prepared hydroxyapatite nanoparticles have a surface area of 58.8 m 2 /g. These nanoparticles can be used in bio medical applications and in the field of nanocomposite structures.

Bio-based calcium carbonate (CaCO3) nanoparticles for drug delivery applications

With the rapid increase in global population, potential water shortage, water quality has become a concern. In some extreme cases such as Arizona, we may have to switch from toilet to tap within the near future. However, our current monitoring methods for drinking water have limitations and do not provide fast and reliable results to deal with these challenges. By using intrinsic fluorescence, microbial contamination in drinking water can be monitored in real-time, continuously, without sample contact and at very low concentration (~50 cells/L). This technology uses intrinsic fluorescence to detect microorganisms. By introducing a pulse, microorganisms can be excited and as a result they will fluoresce. In addition, some of the cellular components (fluorophores) that fluoresce in these microorganisms can be used as indicators to distinguish viable cells, non-viable cells and spores. In our study, three different wavelengths were used to excite specific cellular components. We used UV, Red and Amber light. The fluorophores targeted were reduced pyridines nucleotides (RPNs) and flavins, cytochromes, and calcium dipicolinic acid (DPA) as indicators for viable cells, non-viable cells and spores respectively. The emissions collected allowed us to distinguish viable cells, nonviable cells and spores. By using this method, a wide range of microorganisms such as bacteria, protozoa, amoeba and other microorganisms of concern can be detected.Targeted delivery of a cytotoxic drug using a drug delivery system could maximise the efficacy of the drug and reduce the side effects. Calcium carbonate (CaCO3) nanoparticles are highly porous, biocompatible, biodegradable, and have pH-sensitive properties, which makes them good candidates for biological drug delivery systems. In this study, the nanoparticles were derived from egg shells and studied for their drug loading capacity and cytotoxicity, using human colon adenocarcinoma (SW480), and human dermal fibroblast (HDF) cells. The lactate dehydrogenase (LDH) assay indicated a 50% cytotoxicity for SW480 cells at a concentration of 0.3 mg/ml, but there was no cytotoxic effect observed in HDF cells at the same concentration. The anticancer drug 5-fluorouracil (5-FU) and natural compound indole-3-carbinol (I3C) were loaded into CaCO3 nanoparticles and release profiles were studied. These results showed that the drugs can be loaded in CaCO3 nanoparticles and released efficiently. The drug loaded nanoparticles were more cytotoxic compared to the as-received drugs alone. The 5FU-loaded nanoparticles in pH 1.0, 5.0, and 7.4 yielded a total loading and release of 86.98 µg, 77.83 µg, and 162.60 µg respectively. Depending on the pH of the solution, up to 162.60 µg of 5-FU was loaded and released from 50 milligrams of the particles, whereas, up to 563.47 micrograms of I3C was loaded and released from similarly loaded particles. These preliminary results indicate the potential of bio-based CaCO3 nanoparticles in therapeutic applications.T research focuses on developing an impedance measurement system by Electronic Design Automation (EDA) technology to reduce analog circuits and convert analog biological information into digital data for the ease of processing, analyzing, and storing. The impedance measurement system includes a field-programmable gate array (FPGA) platform, a function generator, and a personal computer. The FPGA’s internal circuit structure includes two analog-to-digital converters (ADC), a baud rate generator, a frequency divider, an up counter, a 2-to-1 multiplexor, a decoder, and a UART transmitter. In order to monitor biological properties and analyze impedance changes, the function generator produces alternating current (AC) signals of various frequencies with specified magnitudes for injecting current into the measured subject. To detect the impedance magnitude and phase, the computer receives the injected AC signal data and the induced signal data from the FPGA through the RS232 serial port. Then, discrete Fourier transform is conducted to obtain the impedance magnitudes and phases angle at various frequencies. A graphical user interface (GUI) in the computer is designed to serve as the gateway through which for the user to observe the measurement results and to view the relationships among various parameters such as frequency, impedance, and biochemical concentration. This electrochemical impedance spectroscopy (EIS) system will be used to measure composite solutions of human serum albumin (HSA) and phosphate buffered saline (PBS) at different concentrations with impedance biosensors. Ming-Lang Chang, J Biosens Bioelectron, 2:4 http://dx.doi.org/10.4172/2155-6210.S1.13

Development and characterization of recycled-HDPE/EVA foam reinforced with babassu coconut epicarp fiber residues

Nowadays, the development of polymeric materials reinforced with residues of vegetal fibers is becoming popular for application in different segments, from the automotive to the civil construction and furniture industry. Vegetal fiber residues may be used as reinforcement of the recycled polymer materials, for instance, to produce foams to packaging or to thermal and acoustic isolation for green building application. This work is focused on the development and characterization of recycled-HDPE/EVA foam reinforced with fiber residues from babassu coconut epicarp. Firstly, composites based on recycled-HDPE/EVA blend reinforced with babassu coconut fiber were obtained by melting extrusion process. The composites were then extruded in a special single screw for foaming. The foam samples were submitted to mechanical tests, density measurement, DSC, TG, and FE-SEM analysis.

Influence of Electron-Beam Irradiation on the Properties of LDPE/EDPM Blend Foams

Closed-cell polyethylene (PE) foams have been extensively used in many applications such as packaging, transportation, sports, construction, and agriculture because of their variety of properties including light weight, chemical resistance, thermal and electrical insulation. The objective of this study is to evaluate the influence of electron-beam irradiation on the properties of LDPE/EPDM blend foams. The LDPE/EPDM blend (80/20 wt%) were prepared by melt extrusion, using a twin-screw extruder machine. The foam structure of LDPE/EPDM blends was obtained by melt extrusion process, using a special single screw for foaming with 1.5 wt% of foaming agent as blowing agent. The foam samples were irradiated by electron-beam at radiation dose of 25, 50, 75 and 100 kGy and submitted to heating in an oven at 100 °C. The specimen tests samples of irradiated and non-irradiated foams were submitted to mechanical tests, DSC, TG analysis and density measurement.