Functionalized Nanolipobubbles Embedded Within a Nanocomposite Hydrogel: a Molecular Bio-imaging and Biomechanical Analysis of the System.

The purpose of this study was to explore the use of molecular bio-imaging systems and biomechanical dynamics to elucidate the fate of a nanocomposite hydrogel system prepared by merging FITC-labeled nanolipobubbles within a cross-linked hydrogel network. The nanocomposite hydrogel system was characterized by size distribution analysis and zeta potential as well as shears thinning behavior, elastic modulus (G'), viscous loss moduli (G"), TEM, and FTIR. In addition, molecular bio-imaging via Vevo ultrasound and Cell-viZio techniques evaluated the stability and distribution of the nanolipobubbles within the cross-linked hydrogel. FITC-labeled and functionalized nanolipobubbles had particle sizes between 135 and 158 nm (PdI = 0.129 and 0.190) and a zeta potential of -34 mV. TEM and ultrasound imaging revealed the uniformity and dimensional stability of the functionalized nanolipobubbles pre- and post-embedment into the cross-linked hydrogel. Biomechanical characterization of the hydrogel by shear thinning behavior was governed by the polymer concentration and the cross-linker, glutaraldehyde. Ultrasound analysis and Cell-viZio bio-imaging were highly suitable to visualize the fluorescent image-guided nanolipobubbles and their morphology post-embedment into the hydrogel to form the NanoComposite system. Since the nanocomposite is intended for targeted treatment of neurodegenerative disorders, the distribution of the functionalized nanolipobubbles into PC12 neuronal cells was also ascertained via confocal microscopy. Results demonstrated effective release and localization of the nanolipobubbles within PC12 neuronal cells. The molecular structure of the synthetic surface peptide remained intact for an extended period to ensure potency for targeted delivery from the hydrogel ex vivo. These findings provide further insight into the properties of nanocomposite hydrogels for specialized drug delivery.

Understanding performance limitation and suppression of leakage current or self-discharge in electrochemical capacitors: a review.

Self-discharge is known to have considerable adverse effects on the performance and application of electrochemical capacitors (ECs). Thus, obtaining an understanding of EC self-discharge mechanism(s) and subsequent derivation and solution of EC models, subject to a particular mechanism or combination of mechanisms during charging, discharging and storage of the device, is the only way to solve problems associated with EC self-discharge. In this review, we summarize recent progress with respect to EC self-discharge by considering the two basic types, electric double-layer capacitors (EDLC) and pseudocapacitors, and their hybrids with their respective charge storage mechanisms, distinguishable self-discharge mechanisms, charge redistribution and charge/energy loss during self-discharge. It was clearly observed that most of the voltage reduction is not purely due to the self-discharge effect but is basically due to redistribution of charge carriers deep inside pores and can therefore be retrieved from a capacitor during long-time discharging. Tuning the self-discharge rate is therefore feasible for single-walled carbon nanotube (SWNT) ECs and can be achieved by simply adjusting the surface chemistry of the nanotubes. The effects of surface chemistry modification on EC self-discharge are very important in studying and suppressing the self-discharge process and will benefit potential applications of ECs with respect to energy retention. Self-discharge can be averted by the use of redox couples that are transformed to insoluble species via electrolysis and adsorbed onto the activated carbon electrode in redox-couple EDLCs, thus transforming the EDLC electrolyte into a material that can store charge. Self-discharge in ECs can also be successfully suppressed by utilizing an ion-interchange layer (ion-exchange membrane), separator or CuSO4 mobile electrolyte that can be converted into an insoluble species by electrolysis during the charge/discharge process. This will help in producing a modern-day blueprint for ECs with high capacitance and improved energy sustainability.

The influences of operating conditions and design configurations on the performance of symmetric electrochemical capacitors.

The influence of different charging current densities, charging times and several structural designs on symmetric electrochemical capacitor (EC) performance, including capacitance, energy density and power density, has been investigated via modelling and simulation. Understanding the effects of different operating conditions and structural design variables on a capacitor's performance will guide in the optimal design and fabrication of high performance ECs. The operating conditions and design configurations examined were charging current density, charging times, electrode and electrolyte effective conductivity, electrode thickness and electrode porosity. The results reveal that ECs with low electrode and electrolyte effective conductivities can only be effectively charged at low current density for long times. ECs with a high concentration of impurity ions or redox species exhibit high self-discharge rates, and fast charging of the ECs greatly reduces the self-discharge rate, compared to slow charging, provided that the effective conductivities of the electrode and electrolyte are high enough. The simulation showed the typical electrode length scale over which the liquid potential drop occurs and electrode utilization can be employed as a design parameter to optimize electrode thickness (effective thickness) for ECs designed to operate under a specific current density range. The expression for electrode utilization (u) and the guidelines that can also be used to determine optimum electrode thickness/effective thickness (100% electrode utilization), optimum charging time and optimum current density in a cell of a given voltage and effective conductivity of electrode and electrolyte, were derived. The energy and power density of ECs were increased when the electrode thickness was reduced in the given charging conditions. The Ragone plots can be used to select optimum electrode dimensions to attain given energy and power density specifications.

Carbon Nanotube Synthesis Using Coal Pyrolysis.

This study investigates carbon nanotube (CNT) production from coal pyrolysis wherein the output gases are used in a chemical vapor deposition reactor. The carbon products are similar to those using commercial coal gas as feedstock, but coal is a relatively cheaper feedstock compared to high purity source gases. A Gibbs minimization model has been developed to predict the volume percentages of product gases from coal pyrolysis. Methane and carbon monoxide were the largest carbon components of the product stream and thus formed the primary source for CNT synthesis. Both the model and the observations showed that increasing the furnace temperature led to a decrease in the absolute quantities of "useful" product gases, with the optimal temperature between 400 and 500 °C. Based on the experimental data, a kinetic rate law for CNT from coal pyrolysis was derived as d[CNT]/dt = K([CO][CH4])(1/2), where K is a function of several equilibrium constants representing various reactions in the CNT formation process.

Design and pharmaceutical evaluation of a nano-enabled crosslinked multipolymeric scaffold for prolonged intracranial release of Zidovudine.

PURPOSE: Nanomedicine explores and allows for the development of drug delivery devices with superior drug uptake, controlled release and fewer drug side-effects. This study explored the use of nanosystems to formulate an implantable drug delivery device capable of sustained zidovudine release over a prolonged period. METHODS: Pectin and alginate nanoparticles were prepared by applying a salting out and controlled gelification approach, respectively. The nanoparticles were characterized by attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS) and were further evaluated for zidovudine (AZT) entrapment efficiency. Multipolymeric scaffolds were prepared by crosslinking carboxymethyl cellulose, polyethylene oxide and epsilon caprolactone for entrapment of zidovudine-loaded alginate nanoparticles to impart enhanced controlled release of zidovudine over the time period. Swelling and textural analysis were conducted on the scaffolds. Prepared scaffolds were treated with hydrochloric acid (HCl) to reduce the swelling of matrix in the hydrated environment thereby further controlling the drug release. Drug release studies in phosphate buffered saline (pH 7.4, 37°C) were undertaken on both zidovudine-loaded nanoparticles and native scaffolds containing alginate nanoparticles. RESULTS: A higher AZT entrapment efficiency was observed in alginate nanoparticles. Biphasic release was observed with both nanoparticle formulations, exhibiting an initial burst release of drug within hours of exposure to PBS, followed by a constant release rate of AZT over the remaining 30 days of nanoparticle analysis. Exposure of the scaffolds to HCl served to reduce the drug release rate from the entrapped alginate nanoparticles and extended the AZT release up to 30 days. CONCLUSIONS: The crosslinked multipolymeric scaffold loaded with alginate nanoparticles and treated with 1% HCl showed the potential for prolonged delivery of zidovudine over a period of 30 days and therefore may be a potential candidate for use as an implantable device in treating Aids Dementia Complex.

The bioethanol industry in sub-Saharan Africa: history, challenges, and prospects.

Recently, interest in using bioethanol as an alternative to petroleum fuel has been escalating due to decrease in the availability of crude oil. The application of bioethanol in the motor-fuel industry can contribute to reduction in the use of fossil fuels and in turn to decreased carbon emissions and stress of the rapid decline in crude oil availability. Bioethanol production methods are numerous and vary with the types of feedstock used. Feedstocks can be cereal grains (first generation feedstock), lignocellulose (second generation feedstock), or algae (third generation feedstock) feedstocks. To date, USA and Brazil are the leading contributors to global bioethanol production. In sub-Saharan Africa, bioethanol production is stagnant. During the 1980s, bioethanol production has been successful in several countries including Zimbabwe, Malawi, and Kenya. However, because of numerous challenges such as food security, land availability, and government policies, achieving sustainability was a major hurdle. This paper examines the history and challenges of bioethanol production in sub-Saharan Africa (SSA) and demonstrates the bioethanol production potential in SSA with a focus on using bitter sorghum and cashew apple juice as unconventional feedstocks for bioethanol production.

Surface-engineered nanoliposomes by chelating ligands for modulating the neurotoxicity associated with ß-amyloid aggregates of Alzheimer's disease.

PURPOSE: To develop chelating ligand-bound nanoliposomes (NLPs) for the prevention and reversal of ß-Amyloid (Aß) aggregation associated with promoting neurotoxicity in Alzheimer disease (AD). METHODS: Four different chelating ligands (CuAc, EDTA, histidine and ZnAc) were surface-engineered onto NLPs using either covalent or non-covalent conjugation. Successful conjugation of chelating ligands onto the surface of NLPs was confirmed by characterization studies: SEM, TEM and FTIR analysis. Chelation energetics of EDTA with Cu(II)/Zn(II)-Aß(10-21) and nanoformation of emulsified polymers were computed and corroborated with experimental and analytical data using chemometric molecular modeling. RESULTS: The modified NLPs produced were spherical in shape, 127-178 nm in size, with polydispersity index from 0.217-0.920 and zeta potential range of -9.59 to -37.3 mV. Conjugation efficiencies were 30-76 %, which confirmed that chelating ligands were attached to the NLP surface. CONCLUSIONS: In vitro and ex vivo results elucidated the effectiveness of chelating ligand-bound NLPs for prevention of CuAß(1-42) or ZnAß(1-42) aggregate buildup associated with neurotoxicity in PC12 neuronal cells, as well as promotion of intracellular uptake in the presence of Cu(II) or Zn(II) metal ions.

Nanoparticles toxicity and their routes of exposures.

The new scientific innovation of engineering nanoparticles (NPs) at the atomic scale of 100 nm or less, has led to numerous novel and useful wide applications in electronics, chemicals, environmental protection, biological medicine. Manufacturers and consumers of the nanoparticles-related industrial products however, are likely to be exposed to these engineered nanomaterials which have various physical and chemical properties. These nanosize particles are likely to increase an unnecessary infinite toxicological effect on animals and environment, although their toxicological effects associated with human exposure are still unknown. In order to understand the effects of these exposures, this review seeks to examine the various toxicological portal routes associated with NPs exposures. These NPs can enter the host systems via skin spores, debilitated tissues, injection, olfactory, respiratory and intestinal tracts. These uptake routes of NPs may be intentional or unintentional. Their entry may lead to various diversified adverse biological effects. Until a clearer picture emerges, the limited data available suggest that caution must be exercised when potential exposures to NPs are encountered. Methods used in determining NPs portal of entry into experimental animals include pharyngeal instillation, injection, inhalation, cell culture lines and gavage exposures. This review also provides a step by step systematic approach for the easy identification and addressing of occupational health hazards arising from NPs.

Formulation and evaluation of a salted-out isoniazid-loaded nanosystem.

The purpose of this study was to develop a drug-loaded nanosystem that has the ability to achieve flexible yet rate-controlled release of model drug isoniazid (INH) employing either an aqueous or emulsion-based salting-out approach. Formulation conditions were aimed at reducing the polymeric size with subsequent rate-modulated INH release patterns from the polymeric nanosystem. The emulsion-based salted-out nanosystems had particle sizes ranging from 77-414 nm and a zeta potential of -24 mV. The dispersant dielectric constant was set at 78.5 and a conductivity of 3.99 mS/cm achieved. The reduced nanosystem size of the aqueous-based approach has demonstrated an intrinsically enhanced exposure of methacrylic acid-ethyl acrylate to zinc sulphate which was employed as a crosslinking reagent. This resulted in robustly interconnected polymeric supports in which INH was efficiently embedded and subsequently released. The multi-layer perceptron data obtained showed that the aqueous and emulsion-based salting out approaches had Power (law) (MSE = 0.020) and Linear (MSE = 0.038) relationships, respectively. Drug release from the nanosystems occurred in two phases with an initial burst-release in aqueous-based nanosystems (30-100%) and significantly lower bursts observed in emulsion-based nanosystems (20-65%) within the first 2 h. This was followed by a gradual exponential release phase over the remaining 12 h. The nanosystems developed demonstrated the ability to control the release of INH depending on the formulation approach adopted.

Data on cost analysis of drilling mud displacement during drilling operation.

The focus of this research was to present a data article for analyzing the cost of displacing a drilling fluid during the drilling operation. The cost of conventional Spud, KCl and Pseudo Oil base (POBM) muds used in drilling oil and gas wells are compared with that of a Reversible Invert Emulsion Mud. The cost analysis is limited to three sections for optimum and effective Comparison. To optimize drilling operations, it is important that we specify the yardstick by which drilling performance is measured. The most relevant yardstick is the cost per foot drilled. The data have shown that the prices for drilling mud systems are a function of the mud system formulation cost for that particular mud weight and maintenance per day. These costs for different mud systems and depend on the base fluid. The Reversible invert emulsion drilling fluid, eliminates the cost acquired in displacing Pseudo Oil Based mud (POBM) from the well, possible formation damage (permeability impairment) resulting from the use of viscous pill in displacing the POBM from the wellbore, and also eliminates the risk of taking a kick during mud change-over. With this reversible mud system, the costs of special fluids that are rarely applied for the well-completion purpose (cleaning of thick mud filter cake) may be reduced to the barest minimum.

Performance of Carbon Nanotube/Polysulfone (CNT/Psf) Composite Membranes during Oil-Water Mixture Separation: Effect of CNT Dispersion Method.

Effect of the dispersion method employed during the synthesis of carbon nanotube (CNT)/polysulfone-infused composite membranes on the quality and separation performance of the membranes during oil-water mixture separation is demonstrated. Carbon nanotube/polysulfone composite membranes containing 5% CNT and pure polysulfone membrane (with 0% CNT) were synthesized using phase inversion. Three CNT dispersion methods referred to as Method 1 (M1), Method 2 (M2), and Method 3 (M3) were used to disperse the CNTs. Morphology and surface property of the synthesized membranes were checked with scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, respectively. Separation performance of the membranes was evaluated by applying the membrane to the separation of oil-water emulsion using a cross-flow filtration setup. The functional groups obtained from the FTIR spectra for the membranes and the CNTs included carboxylic acid groups (O-H) and carbonyl group (C=O) which are responsible for the hydrophilic properties of the membranes. The contact angles for the membranes obtained from Method 1, Method 2, and Method 3 were 76.6° ± 5.0°, 77.9° ± 1.3°, and 77.3° ± 4.5°, respectively, and 88.1° ± 2.1° was obtained for the pure polysulfone membrane. The oil rejection (OR) for the synthesized composite membranes from Method 1, Method 2, and Method 3 were 48.71%, 65.86%, and 99.88%, respectively, indicating that Method 3 resulted in membrane of the best quality and separation performance.

Evaluation of Physicochemical Properties of South African Cashew Apple Juice as a Biofuel Feedstock.

Cashew apple juice (CAJ) is one of the feedstocks used for biofuel production and ethanol yield depends on the physical and chemical properties of the extracted juice. As far as can be ascertained, information on physical and chemical properties of South African cashew apple juice is limited in open literature. Therefore, this study provides information on the physical and chemical properties of the South African cashew apple juice. Physicochemical characteristics of the juice, such as specific gravity, pH, sugars, condensed tannins, Vitamin C, minerals, and total protein, were measured from a mixed variety of cashew apples. Analytical results showed the CAJ possesses specific gravity and pH of 1.050 and 4.52, respectively. The highest sugars were glucose (40.56 gL(-1)) and fructose (57.06 gL(-1)). Other chemical compositions of the juice were condensed tannin (55.34 mgL(-1)), Vitamin C (112 mg/100 mL), and total protein (1.78 gL(-1)). The minerals content was as follows: zinc (1.39 ppm), copper (2.18 ppm), magnesium (4.32 ppm), iron (1.32 ppm), sodium (5.44 ppm), and manganese (1.24 ppm). With these findings, South African CAJ is a suitable biomass feedstock for ethanol production.

Development and in vivo evaluation of an implantable nano-enabled multipolymeric scaffold for the management of AIDS dementia complex (ADC).

This study reports the use of biocompatible and biodegradable polymers for the formulation and design of an implantable multipolymeric drug delivery device (MDDD) for the management of AIDS dementia complex (ADC), a debilitating condition affecting the cognitive, motor and behavioral systems in HIV+ individuals. A 3-factor Box-Behnken statistical design was employed for the optimization of nanoparticle and multipolymeric scaffold formulations. Fifteen formulations were generated using the Box-Behnken template, which were assessed for physicochemical and physicomechanical characterization. The optimised nanoparticle formulation yielded nanoparticles measuring 68.04nm in size and zeta potential (ZP) of -13.4mV was calculated for the colloidal system. In an attempt to further retard drug release and to formulate a device for implantation in the frontal lobe of the brain, nanoparticles were dispersed within a multipolymeric matrix. Matrix erosion was calculated at 28% for multipolymeric scaffold and a matrix resilience of 4.451% was observed 30 days post exposure to PBS, indicating slow degradation of the MDDD. In vivo studies showed 12.793ng/mL and 35.225ng/mL AZT level in plasma and CSF. In view of the physicomechanical properties, in vitro and in vivo drug release kinetics of MDDD makes it a potential candidate for the management of the ADC.

A carbon nanotube-infused polysulfone membrane with polyvinyl alcohol layer for treating oil-containing waste water.

A carbon nanotube (CNT) integrated polymer composite membrane with a polyvinyl alcohol barrier layer has been prepared to separate oil from water for treatment of oil-containing waste water. The CNTs were synthesised using chemical vapour deposition, and a phase inversion method was employed for the blending of the CNTs in the polymer composite solution for casting of the membrane. Relative to the baseline polymer, an increase of 119% in the tensile strength, 77% in the Young's modulus and 258% in the toughness is seen for a concentration of 7.5% CNTs in the polymer composite. The permeate through the membrane shows oil concentrations below the acceptable 10 mg/L limit with an excellent throughput and oil rejection of over 95%.

Ligand-functionalized nanoliposomes for targeted delivery of galantamine.

The purpose of this study was to design ligand-functionalized nanoliposomes that are proficient in providing effective intracellular delivery of an alkaloid drug (galantamine) into PC12 neuronal cells in response to managing Alzheimer's disease (AD). Ligand-functionalized nanoliposomes were produced and validated for their physicochemical properties, in silico molecular mechanics energy relationships, ex vivo cytotoxicity, peptide coupling efficiency (PCE), drug entrapment efficiency (DEE), drug release, fluorometry and confocal microscopy. Particle sizes of the nanoliposomes ranged from 127 nm to 165 nm (PdI=0.39-0.03), zeta potential values of -18 mV to -36 mV, PCE from 40% to 78% while DEE ranged from 42% to 79%. The surface morphology of the nanoliposomes was stable, spherically and uniform in shape. Thermal behavior and Fourier transform infrared (FTIR) analyses confirmed that galantamine and the peptide-ligand were incorporated into the inner core and surface of the nanoliposomes, respectively. The optimized formulation showed sustained drug release (30% of drug released within 48 h). Fluorometry and confocal microscopy revealed that the ligand-functionalized nanoliposomes facilitated galantamine uptake into PC12 neuronal cells via the Serpin Enzyme Complex Receptor in a mediated manner. CytoTox-Glo™ cytotoxicity assay established the low cytotoxicity on PC12 neuronal cells when exposed to native nanoliposomes and the ligand-functionalized nanoliposomes. Response surface analysis demonstrated there was a high degree of correlation between the experimental and fitted values. Furthermore, ex vivo studies showed that the high galantamine accumulation into PC12 neuronal cells was influenced by the post-engineering of peptides on the surface of the galantamine-loaded nanoliposomes. MMER analysis aptly corroborated the experimental findings.

The heterogeneous coagulation and flocculation of brewery wastewater using carbon nanotubes.

Coagulation and flocculation treatment processes play a central role in the way wastewater effluents are managed. Their primary function is particle removal that can impart colour to a water source, create turbidity, and/or retain bacterial and viral organisms. This study was carried out to investigate whether carbon nanotubes (CNTs) can be used as heterogeneous coagulants and/or flocculants in the pretreatment of brewery wastewater. A series of experiments were conducted in which the efficiencies of pristine and functionalised CNTs were compared with the efficiency of traditional ferric chloride in a coagulation/flocculation process. Turbidity and chemical oxygen demand (COD), including the zeta potential were used to monitor the progress of the coagulation/flocculation process. Both pristine and functionalised CNTs demonstrated the ability to successfully coagulate colloidal particles in the brewery wastewater. Overall, ferric chloride was found to be a more effective coagulant than both the pristine and functionalised CNTs.

Human health effects of residual carbon nanotubes and traditional water treatment chemicals in drinking water.

The volume of industrial and domestic wastewater is increasing significantly year by year with the change in the lifestyle based on mass consumption and mass disposal brought about by the dramatic development of economies and industries. Therefore, effective advanced wastewater treatment is required because wastewater contains a variety of constituents such as particles, organic materials, and emulsion depending on the resource. However, residual chemicals that remain during the treatment of wastewaters form a variety of known and unknown by-products through reactions between the chemicals and some pollutants. Chronic exposure to these by-products or residual chemicals through the ingestion of drinking water, inhalation and dermal contact during regular indoor activities (e.g., showering, bathing, cooking) may pose cancer and non-cancer risks to human health. For example, residual aluminium salts in treated water may cause Alzheimer's disease (AD). As for carbon nanotubes (CNTs), despite their potential impacts on human health and the environment having been receiving more and more attention in the recent past, existing information on the toxicity of CNTs in drinking water is limited with many open questions. Furthermore, though general topics on the human health impacts of traditional water treatment chemicals have been studied, no comparative analysis has been done. Therefore, a qualitative comparison of the human health effects of both residual CNTs and traditional water treatment chemicals is given in this paper. In addition, it is also important to cover and compare the human health effects of CNTs to those of traditional water treatment chemicals together in one review because they are both used for water treatment and purification.

Composite polylactic-methacrylic Acid copolymer nanoparticles for the delivery of methotrexate.

The purpose of this study was to develop poly(lactic acid)-methacrylic acid copolymeric nanoparticles with the potential to serve as nanocarrier systems for methotrexate (MTX) used in the chemotherapy of primary central nervous system lymphoma (PCNSL). Nanoparticles were prepared by a double emulsion solvent evaporation technique employing a 3-Factor Box-Behnken experimental design strategy. Analysis of particle size, absolute zeta potential, polydispersity (Pdl), morphology, drug-loading capacity (DLC), structural transitions through FTIR spectroscopy, and drug release kinetics was undertaken. Molecular modelling elucidated the mechanisms of the experimental findings. Nanoparticles with particle sizes ranging from 211.0 to 378.3 nm and a recovery range of 36.8-86.2 mg (Pdl ≤ 0.5) were synthesized. DLC values were initially low (12 ± 0.5%) but were finally optimized to 98 ± 0.3%. FTIR studies elucidated the comixing of MTX within the nanoparticles. An initial burst release (50% of MTX released in 24 hours) was obtained which was followed by a prolonged release phase of MTX over 84 hours. SEM images revealed near-spherical nanoparticles, while TEM micrographs revealed the presence of MTX within the nanoparticles. Stable nanoparticles were formed as corroborated by the chemometric modelling studies undertaken.

Design, biometric simulation and optimization of a nano-enabled scaffold device for enhanced delivery of dopamine to the brain.

This study focused on the design, biometric simulation and optimization of an intracranial nano-enabled scaffold device (NESD) for the site-specific delivery of dopamine (DA) as a strategy to minimize the peripheral side-effects of conventional forms of Parkinson's disease therapy. The NESD was modulated through biometric simulation and computational prototyping to produce a binary crosslinked alginate scaffold embedding stable DA-loaded cellulose acetate phthalate (CAP) nanoparticles optimized in accordance with Box-Behnken statistical designs. The physicomechanical properties of the NESD were characterized and in vitro and in vivo release studies performed. Prototyping predicted a 3D NESD model with enhanced internal micro-architecture. SEM and TEM revealed spherical, uniform and non-aggregated DA-loaded nanoparticles with the presence of CAP (FTIR bands at 1070, 1242 and 2926 cm(-1)). An optimum nanoparticle size of 197 nm (PdI=0.03), a zeta potential of -34.00 mV and a DEE of 63% was obtained. The secondary crosslinker BaCl(2) imparted crystallinity resulting in significant thermal shifts between native CAP (T(g)=160-170 degrees C; T(m)=192 degrees C) and CAP nanoparticles (T(g)=260 degrees C; T(m)=268 degrees C). DA release displayed an initial lag phase of 24 h and peaked after 3 days, maintaining favorable CSF (10 microg/mL) versus systemic concentrations (1-2 microg/mL) over 30 days and above the inherent baseline concentration of DA (1 microg/mL) following implantation in the parenchyma of the frontal lobe of the Sprague-Dawley rat model. The strategy of coupling polymeric scaffold science and nanotechnology enhanced the site-specific delivery of DA from the NESD.

Cytotoxicity of purified cassava linamarin to a selected cancer cell lines.

Cassava (Manihot esculenta Crantz) is a known source of linamarin, but difficulties associated with its isolation have prevented it from being exploited as a major source. A batch adsorption process using activated carbon proved successful in its isolation, with ultrafiltration playing a pivotal role in its purification. Thirty-two minutes of contact time was required for 60 g of extract, yielding 1.7 g of purified product. Picrate paper, infra-red and 'HNMR analysis confirmed the presence and structure of linamarin. Cytotoxic effects of linamarin on MCF-7, HT-29 and HL60 cells were determined using the MTT assay. Cytotoxic effects were significantly increased in the presence of linamarase (P-glucosidase), with a 10-fold decrease in the IC50 values obtained for HL-60 cells. This study thus describes a method for the isolation and purification of linamarin from cassava, as well as its cytotoxicity potential.