Ali Hilal-Alnaqbi

RF Microalgal lipid content characterization

Most conventional techniques for the determination of microalgae lipid content are time consuming and in most cases are indirect and require excessive sample preparations. This work presents a new technique that utilizes radio frequency (RF) for rapid lipid quantification, without the need for sample preparation. Tests showed that a shift in the resonance frequency of a RF open-ended coaxial resonator and a gradual increase in its resonance magnitude may occur as the lipids content of microalgae cells increases. These response parameters can be then calibrated against actual cellular lipid contents and used for rapid determination of the cellular lipids. The average duration of lipid quantification using the proposed technique was of about 1 minute, which is significantly less than all other conventional techniques, and was achieved without the need for any time consuming treatment steps.

Fibre-in-Fibre Bioartificial Liver device: initial in vitro testing

Transplantation is the proven treatment for acute liver failure and in severe cases, affective Bioartificial Liver (BAL) support may provide a bridge to transplantation. This paper describes in vitro evaluation of a novel Fibre-in-Fibre BAL. It is a conventional fibre cartridge with three discrete compartments. Bovine blood is used to assess Oxygen transfer performance of the FIF bioreactor. The tests were carried according to ISO test protocols. Blood flow rate, number of fibre-in-fibre pairs and haemoglobin concentration, CHb are used to assess the oxygen transfer rates. The results demonstrated that the FIF bioreactor provides good gas transfer support.

Dielectrophoresis based focusing in microfluidic devices

This document presents the mathematical model of a microfluidic device employing dielectrophoresis for purposes of 3D-focusing. The electrode configuration consists of multiple interdigitated transducer electrodes on either side of the bottom surface of the microchannel. The model consists of three equations of motion, one for each direction, equation of electric potential and electric field, and Navier-Stokes equation for fluid flow. The model accounts for forces such as inertia, gravity, buoyancy, and dielectrophoresis. The model is used for analyzing the influence of operating and geometric parameters on focusing. It is observed that the electrode configuration can achieve 3D-focusing irrespective of the radius and initial location of the micro-scale entity, volumetric flow rate, and applied voltage.

Visualization and quantification of oil in single microalgal cells

Microalgae are considered a promising source of oil for biodiesel production. This work reports an estimation method of oil content inside living microalgal cells by visualization and image processing techniques. This approach was used to analyze the time course of oil accumulation patterns in Nile Red-stained microalgal cells of Scenedesmus sp. cultivated in nitrogen-deficient medium used to induce oil accumulation in microalgal cells. Nile Red staining is a widely used technique for studying oil content of microalgal cells. The intracellular oil content was estimated by mathematically evaluating the oil volume inside the stained cell. This novel visualization approach has the potential to be used in ex vivo studies of oil content at the level of single microalgal cells. This method can also be applied to other types of oil-producing microorganisms because of its accuracy, precision, and reduction in the time and effort required for optimization.

Bilirubin detoxification using different phytomaterials: characterization and in vitro studies

Background Activated carbon (AC) is a common adsorbent that is used in both artificial and bioartificial liver devices. Methods Three natural materials – date pits of Phoenix dactylifera (fruit), Simmondsia chinensis (jojoba) seeds, and Scenedesmus spp. (microalgae) – were used in the present investigation as precursors for the synthesis of AC using physical activation. The chemical structures and morphology of AC were analyzed. Then, AC’s bilirubin adsorption capacity and its cytotoxicity on normal liver (THLE2) and liver cancer (HepG2) cells were characterized. Results Compared with the other raw materials examined, date-pit AC was highly selective and showed the most effective capacity of bilirubin adsorption, as judged by isotherm-modeling analysis. MTT in vitro analysis indicated that date-pit AC had the least effect on the viability of both THLE2 and HepG2 cells compared to jojoba seeds and microalgae. All three biomaterials under investigation were used, along with collagen and Matrigel, to grow cells in 3D culture. Fluorescent microscopy confirmed date-pit AC as the best to preserve liver cell integrity. Conclusion The findings of this study introduce date-pit-based AC as a novel alternative biomaterial for the removal of protein-bound toxins in bioartificial liver devices.

Dielectrophoresis-based 3D-focusing of microscale entities in microfluidic devices: Dielectrophoresis-Based 3D-Focusing of Microscale Entities in Microfluidic Devices

This article presents a validated mathematical model of a dielectrophoresis (DEP)‐based microfluidic device capable of 3D‐focusing microscale entities at any lateral location inside the microchannel. The microfluidic device employs planar, independently controllable, interdigitated transducer (IDT) electrodes on either side of the microchannel. The developed model is used for understanding the influence of different geometric and operating parameters on 3D focusing, and it comprises of motion equation, Navier–Stokes equation, continuity equation, and electric potential equation (Laplace equation). The model accounts for forces associated with inertia, gravity, buoyancy, virtual mass, drag, and DEP. The model is solved using finite difference method. The findings of the study indicate that the 3D focusing possible with the proposed microfluidic device is independent of microscale entitys size and initial position, microchannel height, and volumetric flow rate. In contrast, 3D focusing achievable with the microfluidic device is dependent on the applied electric potential, protrusion width of electrodes, and width of electrode/gap. Additionally, the lateral position of 3D focused can be controlled by varying the applied electric potential. The advantage of the proposed microfluidic device is that it is simple to construct while capable of achieving 3D focusing at any lateral location inside the microchannel.

Adsorption of Bilirubin Toxin in Liver by Chitosan Coated Activated Carbon Prepared from Date Pits

The aim of this work was to develop activated carbon (AC) from date pit powder and evaluate its adsorption efficiency of bilirubin toxin. In order to increase the adsorption capacity of bilirubin, an increase in the surface area is necessary. This increase was achieved through pyrolysis technique and to further increase the absorption capacity of AC when coated with chitosan gel, which contains several groups on its chains that act as interaction sites. Results indicated that the presence of the AC lead to a decrease in bilirubin content and the more the AC added to the sample, the faster the rate of adsorption as well as the higher the capacity of adsorption. A 0.3 M AC concentration shows a 0.82 left over bilirubin fraction after 16 h, while a 0.1 M AC concentration shows a 0.9 bilirubin fraction after the same interval of time. Contact time is another factor that also contributed to the increase in adsorption of bilirubin. It was seen that chitosan coated AC shows an increase in adsorption percentage from about 25% to 96% when left for a longer period of time.

Investigation of DNA Sequences Utilizing Frequency-Selective Nanopore Structures

Newer methodologies that are quick, label-free, reliable, and low-cost for DNA sequencing and identification are currently being explored. High frequency based-scattering parameters provide a reliable measurement platform and technique to characterize DNA bases. Using a modeling approach, this work investigates the utilization of high frequency-selective structure coupled with nanopore technology for nucleotide identification and sequencing. The model envisions a coplanar waveguide structure harboring a small hole with an internal diameter of the order of several nanometers to demonstrate the potential use of high frequency to identify and sequence DNA. When DNA molecule enters the pore, it should cause disturbance in the electromagnetic field. This disturbance should result in a shift in the resonance frequency and its corresponding characteristics, thus enabling nucleotide identification. The frequency response of four different single DNA strands composed exclusively of either A, C, G or T were measured and characterized to extract the corresponding dielectric constants and their corresponding base paired strands. These dielectric constant values were then used to model the presence of the corresponding DNA molecules in the nanopore. The conducted simulations revealed distinctions between the single and double-stranded DNA molecules due to their different and distinct electrical properties.

Analysis of dielectrophoresis based 3D-focusing in microfluidic devices with planar electrodes

This article models a dielectrophoresis based approach for achieving 3D focusing, of micro-scale objects, in microfluidic devices. The microfluidic device employs four planar electrodes; two electrodes each on the top and bottom surface of the microchannel and each slightly protrude into the microchannel. Each electrode establishes electric field with the neighboring electrode on the same and opposite surfaces. The dielectrophoretic force pushes the micro-scale objects both the directions transverse to the flow direction to achieve the desired 3D focusing. The developed model accounts for various forces such as that associated with inertia, sedimentation, drag, and dielectrophoresis. Finite difference method is used for calculating the electric field and dielectrophoretic force as well as the displacements of micro-scale objects in the microchannel. Several geometric and operating parameters influence the trajectory of micro-scale objects. There exists a threshold voltage beyond which there is no increase in levitation height.

Cancer and Biotechnology: A Matchup that Should Never Slowdown

Plant-based treatments propose a very attractive approach for cancer prevention and therapy due to their minimal toxicity and lower-to-nonassociated side effects. About 40% of FDA-approved therapeutic agents are natural-based components or their derivatives. Plant-based components have been reported to have anticancer properties in vivo and in vitro through the modulation of many cancer hallmarks and niche elements, including self-renewal properties of cancer stem cells. Screening for anticancer agents, synthetic or natural-based, requires a reliable disease model. Efforts to mimic in vivo conditions have led to the development of three-dimensional culture system, a biotechnology that allows cells to grow in three dimensions. Nanotechnology is also fast growing into a quite powerful tool to improve quality of life, particularly the life of cancer patients. Clearing away most hurdles that conventional/herbal medicine is often challenged with, nanotechnology can potentially help delivering anticancer herbal drugs more specifically and efficiently. Given the rather gloomy reality of cancer, nanomedicine becomes the major silver lining. A number of successful conjugates of nanoparticle with herbal products are discussed in this chapter.