Heath Edward Misak

Skin cancer treatment by albumin/5-Fu loaded magnetic nanocomposite spheres in a mouse model

Albumin/drug loaded magnetic nanocomposite spheres were fabricated using an oil-in-oil emulsion/solvent evaporation method, and tested on a mouse model (experimental squamous cell carcinoma) to determine the efficacy of the drug delivery system (DDS) on skin cancer. This novel DDS consists of human serum albumin, poly(lactic-co-glycolic acid) (PLGA), 5-fluorouracil (5-Fu), magnetic nanoparticles (10 nm) and fluorescent labeling molecule (diphenylhexatriene). One of the major purposes of using albumin is that it likely provides internal binding to and retention by the inflammatory tissues to reduce the amount of magnetic nanoparticles needed in the drug loaded microspheres (750–1100 nm). This study is aimed at reducing many negative side effects of conventionally used chemotherapy drugs by localizing the chemotherapy drug, controlling the release of the therapeutic agent and encouraging uptake of the DDS into cancerous cells. A group of mice treated with (1) the magnetic targeted DDS were compared to the other three groups, including, (2) DDS without a magnet, (3) 5-Fu local injection, and (4) untreated groups. The fluorescent tracer was ubiquitously identified inside the tumor tissue, and the DDS/tumor tissue boundary presented a leaky interface. The test results clearly showed that the magnetic targeted DDS exhibited significantly superior therapeutic effects in treating the skin cancer, with the increased efficacy to halt the tumor growth.

Albumin-based nanocomposite spheres for advanced drug delivery systems

A novel drug delivery system incorporating human serum albumin, poly(lactic‐co‐glycolic acid, magnetite nanoparticles, and therapeutic agent(s) was developed for potential application in the treatment of diseases such as rheumatoid arthritis and skin cancer. An oil‐in‐oil emulsion/solvent evaporation (O/OSE) method was modified to produce a drug delivery system with a diameter of 0.5–2 μm. The diameter was mainly controlled by adjusting the viscosity of albumin in the discontinuous phase of the O/OSE method. The drug‐release study showed that the release of drug and albumin was mostly dependent on the albumin content of the drug delivery system, which is very similar to the drug occlusion‐mesopore model. Cytotoxicity tests indicated that increasing the albumin content in the drug delivery system increased cell viability, possibly due to the improved biocompatibility of the system. Overall, these studies show that the proposed system could be a viable option as a drug delivery system in the treatment of many illnesses, such as rheumatoid arthritis, and skin and breast cancers.

Cytotoxicity of release products from magnetic nanocomposites in targeted drug delivery

The efficacy of chemotherapy can be significantly improved if the therapeutic agent remains localized at the afflicted area and released at controlled rates. Such a targeted drug delivery can be achieved using magnetic nanocomposite (MNC), which incorporates drug and magnetic nanoparticles in biodegradable polymer microspheres. Reported here are results from an in vitro study on drug release rate and cytotoxicity of other release products from MNC. The model system contains an anti-cancer chemotherapy agent 5-flurouracil (5-FU) and (Co0.5Zn0.5)Fe2O4 in poly(lactic-co-glycolic acid) (PLGA) matrix produced by an oil/oil emulsion technique. Cell proliferation data indicate a sustained release of 5-FU for mouse macrophage cell eradication, whereas other microsphere components of magnetic nanoparticles and PLGA have little cytotoxic effects.

The Addition of Graphene to Polymer Coatings for Improved Weathering

Graphene nanoflakes in different weight percentages were added to polyurethane top coatings, and the coatings were evaluated relative to exposure to two different experimental conditions: one a QUV accelerated weathering cabinet, while the other a corrosion test carried out in a salt spray chamber. After the exposure tests, the surface morphology and chemical structure of the coatings were investigated via atomic force microscopy (AFM) and Fourier transform infrared (FTIR) imaging. Our results show that the addition of graphene does in fact improve the resistance of the coatings against ultraviolet (UV) degradation and corrosion. It is believed that this process will improve the properties of the polyurethane top coating used in many industries against environmental factors.

Electrospun Fibers Incorporated With Hydroxyapatite Nanoparticles and Graphene Nanoflakes for Bone Scaffolding

Sol-gel driven hydroxyapatite (HA) nanoparticles and graphene nanoflakes were incorporated with polycaprolactone (PCL) at different concentrations, and then electrospun at various spinning conditions, such as distance, electrical potential, viscosity and pump speed. The HA nanoparticles were initially amorphous, so they were annealed at elevated temperature (750 °C) for two hours to make them crystalline. Scanning electron microscopy and X-ray diffraction analysis techniques were conducted on the produced nanocomposite fibers. The studies showed that the HA nanoparticles (20–50 nm) and graphene were well distributed in the PCL fibers (500 nm to 5 μm). We believed that such nanoscale biomaterials can accelerate the bone growth and bone regeneration for many patients who are seeking solutions.Copyright

Time-dependent electrical properties of carbon nanotube yarns

Carbon nanotubes (CNTs) are projected as a desirable option to transmit electrical power where specific conductivity is an important consideration. A CNT-yarn was therefore characterized for its ability to transmit power as a function of time. A current–voltage (I–V) relationship was established that showed three distinct regions: linear, non-linear and finally its degradation. The linear region shows a low and constant resistance. The output current did not change with time when the applied constant voltage was in the linear region of the I–V relationship. However, when the applied constant voltage was in the non-linear region the current decreased exponentially and leveled off with time. Under constant current tests, voltage increased only when current level was in the non-linear region. These time-dependent electrical conducting properties can be accounted for by short circuits occurring from the development of a localized red-hot spots in the CNT-yarn in the non-linear region, leading to thermal degradation, as revealed by thermal imaging of the yarn, thermal gravimetric analysis of the CNTs, and SEM images and EDAX of the thermally degraded CNT-yarn. [New Carbon Materials 2015, 30(3): 207–213]

Fabrication and Characterization of Carbon Nanotube Nanocomposites Into 2024-T3 Al Substrates Via Friction Stir Welding Process

Carbon nanotube (CNT)-aluminum (Al) nanocomposites were prepared using friction stir welding (FSW) processing, and then the mechanical properties of these nanostructured materials were determined using the universal MTS machine. The fabrication of the CNT-metal composite consisted of the following steps: (a) homogenizing the CNTs and Al powder at three different ratios: 0/100, 25/75, and 50/50, (b) compacting the mixtures into grooves that were initially machined into the substrate (2024-T3) for the three cases, (c) incorporating CNTs in a substrate by the FSW process, and (d) validating the dispersion of the CNTs into the Al substrates after the characterization steps. Scanning electron microscopy (SEM) analysis and other physical characterization tests (e.g., mechanical, metallography, and fracture surfaces) were conducted on the prepared substrates. Test results showed that CNTs were dispersed and aligned uniquely in the different locations of the metal structures depending on the FSW zones: advancing, retreating, transverse, and stir zone regions. The mechanical properties of each zone were also compared to the distribution of CNTs. The advancing side had the highest amount of CNTs mixed into the aluminum substrate while retaining the yield strength (YS); however, the elongation was reduced. The retreating side had little to no CNTs distributed into the substrate and the mechanical properties were not significantly affected. The stir zone YS had little influence of the CNTs at the lower CNT/Al powder ratio (25/50), but a significant effect was noticed at the higher ratio of 50/50. The elongation to failure was significantly affected for both cases. The transverse zone YS and elongation to failure was significantly reduced by the powder mixtures. These results may open up new possibilities in the aircraft and other manufacturing industries for future development in the field.

Development of low pressure filter testing vessel and analysis of electrospun nanofiber membranes for water treatment

A low-pressure filtration unit incorporated with polymeric electrospun polyvinyl chloride (PVC) fiber membranes was designed and fabricated for the treatment of waste water in order to improve its quality. This custom-made pressure filter was designed according to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). A scanning electron microscope (SEM) was used to characterize the electrospun membranes. In order to increase the hydrophilicity and filtration rates of PVC membranes, a lower dosage of poly (ethylene oxide) was added to the PVC solution prior to the electrospinning process. The filter was found to be well suited for the reduction of larger suspended solids, turbidity, and odor. It was demonstrated that this type of filtration membrane could be manufactured at a lower cost and not require electricity or any other external power source to achieve high flow rates. This technology could even be used to enhance the quality of tap water in many places, such as Africa. Another application could be a pre-filtration of reverse osmosis (RO) or other ultrafine filtration systems, to increase the life of the primary filter while decreasing fouling and maintenance.Copyright

Cytotoxicity of magnetic nanocomposite spheres for possible drug delivery systems

Cytotoxicity test is a rapid and standardized in vitro method to determine the harmful effects of materials used for biomedical purposes, such as drug carriers, implants and their coatings, biosensors and surgical/medical devices. In the present study, sol-gel driven nickel ferrite (NiFe2 O4 ) and cobalt ferrite (CoFe2 O4 ) nanoparticles (10–25 nm) at different concentrations were incorporated into biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), using oil-in-oil emulsion/solvent evaporation technique, and then the cytotoxicity of magnetic nanocomposite spheres was characterized using raw cells. The test provides the toxicity of the products prior to their real applications, which may limit animal experimentation, remove potential toxic compounds and reduce the downstream costs. The cytotoxicity results showed that both magnetic nanocomposite spheres were toxic at some degree to the raw cells; however, the cobalt ferrite nanoparticles in nanocomposite spheres are more toxic than the nickel ferrite nanoparticles.Copyright

Effect of UVB Light Exposure on Tensile Behavior of Carbon Nanotube Sheet

The effects of ultraviolet B (UVB) exposure on the tensile behavior of CNT sheet was investigated in this study. Two types of CNT sheet, one acid treated and one un-treated, were directly exposed to UVB light for 500 hours. The exposure was done using a UVB lamp inside a dark chamber under room temperature ambient condition. The microstructure of the CNT sheets were studied both prior to and after UVB exposure using a scanning electron microscope. Upon completion of the exposure duration, the CNT sheet test coupons were tested mechanically in tension using a microtester to evaluate the tensile strength and behavior. The results were compared to those of the CNT sheet test coupons that were not exposed to UVB light. It was observed that the strength of the acid treated CNT sheet decreased after UVB exposure while the strength of the un-treated CNT sheet increased. Apart from slight changes in stiffness, the overall mechanical behavior with increasing applied load did not show much change after the exposure to UVB light. The microscopic analysis showed evidences of morphological changes in the CNT microstructure upon UVB exposure. These changes supported the change in mechanical strength as a result of the UVB exposure.