AC Electrokinetic Effect of V-Electrode Pattern on Microfluids

Electrokinetics has been used for guiding, pumping, and manipulating microfluidic particles for many years in the field of Biomedical, Microbiology, Chemistry, Medicine, and other fields of research, which makes it a ubiquitous tool for the multidisciplinary research on microfluidics. Between these two Alternating Current (AC) Electrokinetics have been proven to be more feasible for the researcher than the other one. In this research, we have investigated AC Electrokinetics and s effect on a new electrode configuration called V-electrode pattern. The V-electrode has been inspired and modified from the previous research work on the Orthogonal Electrode Pattern. In this research, this new electrode configuration has been analyzed using different types of setups, fabrication methods, and different fluidic conditions

Simple, Cost-Effective Fabrication, and Flow Dynamics Analysis of a Passive Microfluidic Mixer Using 3D Printing and Soft Lithography

Simple and low-cost fabrication of microfluidic devices has attracted considerable attention among researchers. The traditional soft lithography fabrication method requires expensive equipment like a UV exposure system and mask fabrication facility. In this work, an alternative and low-cost UV exposure system was introduced along with an alternative mask fabrication system. A previously reported passive microfluidic mixer was fabricated successfully using this modified soft lithography method. Challenges were presented during this modified fabrication method. Another emerging potential alternative for the fabrication of microfluidic mixers is 3D printing. It was also used in this experiment to fabricate a passive micromixer. This method is well known for rapid prototyping and the creations of complex structures. However, this method has several disadvantages like optical transparency, lower resolution fabrication, difficulties in flow characterization, etc. These problems were addressed, and the solutions were discussed in this work. Comparative analysis between 3D printing and soft lithography fabrication was presented. Flow characterization inside the 3D printed micromixer was carried out using the microparticulate image velocimetry (micro-PIV) system. It explains how the geometrical shape of the micromixer accelerates the natural diffusion process to mix the different fluid streams. Finally, a 3D numerical simulation of the passive micromixer was carried out to visualize the flow dynamics inside the micromixer. The flow pattern found from the numerical simulation and the experimental flow characterization is analogous. These observations could play an important role to design and fabricate cost-effective micromixers for lab-on-a-chip devices

Effect of Non-Planar Tungsten V-Electrode Pattern in a 3D Printed Microfluidic System

Manipulation, guiding, and focusing of particles is an important phenomenon in the area of biomedical research. In most cases, particles are suspended in a microfluidic environment. These microfluidic environments can be high or low conductive. Most importantly these flows seeded with the micro-particles are manipulated and guided in microfluidic channels. Microfluidic channels have very low dimensions and considering the flow rate the characteristic of the flow in a microfluidic channel is laminar in nature. There are many micromachining methods available for fabricating microfluidic channels such as soft-lithography, wet etching, electroforming, PDMS molding, laser ablation followed by wet etching but in most of these cases, a microfabrication facility is required which is very costly in nature. Now a days 3D printing process is widely used to design microfluidic channels as a cheap process for conducting laboratory experiments. In this work, a 3D printed microfluidic channel fabrication process was presented along with a CAD drawing with microstructural dimension analysis. Previously V-electrode pattern was used in the static fluid system. In this work, a V-elect rode pattern was inserted in the microfluidic system for the first time to analyze the behavior of the flowing fluid of different conductivity under the application of AC current. The flow characteristics were presented and analyzed with the Reynolds number and the flow region of maximum velocity before and after the implementation of the AC electric field. The direction of the flow was also observed in the V-shaped microfluidics environment

Neuromodulatory Effects of Hesperidin in Mitigating Oxidative Stress in Streptozotocin Induced Diabetes

Oxidative stress has been implicated in pathogenesis of streptozotocin- (STZ-) induced diabetes mellitus and its complication in central nervous system (CNS). Recent studies have provided insights on antioxidants and their emergence as potential therapeutic and nutraceutical. The present study examined the hypothesis that hesperidin (HP) ameliorates oxidative stress and may be a limiting factor in the extent of CNS complication following diabetes. To test this hypothesis rats were divided into four groups: control, diabetic, diabetic-HP treated, and vehicle for HP treatment group. Diabetes mellitus was induced by a single injection of STZ (65 mg/kg body weight). Three days after STZ injection, HP was given (50 mg/kg b.wt. orally) once daily for four weeks. The results of the present investigation suggest that the significant elevated levels of oxidative stress markers were observed in STZ-treated animals, whereas significant depletion in the activity of nonenzymatic antioxidants and enzymatic antioxidants was witnessed in diabetic rat brain. Neurotoxicity biomarker activity was also altered significantly. HP treatment significantly attenuated the altered levels of oxidative stress and neurotoxicity biomarkers. Our results demonstrate that HP exhibits potent antioxidant and neuroprotective effects on the brain tissue against the diabetic oxidative damage in STZ-induced rodent model

Melatonin pre-treatment mitigates SHSY-5Y cells against oxaliplatin induced mitochondrial stress and apoptotic cell death.

Oxaliplatin (Oxa) treatment to SH-SY5Y human neuroblastoma cells has been shown by previous studies to induce oxidative stress, which in turn modulates intracellular signaling cascades resulting in cell death. While this phenomenon of Oxa-induced neurotoxicity is known, the underlying mechanisms involved in this cell death cascade must be clarified. Moreover, there is still little known regarding the roles of neuronal mitochondria and cytosolic compartments in mediating Oxa-induced neurotoxicity. With a better grasp of the mechanisms driving neurotoxicity in Oxa-treated SH-SY5Y cells, we can then identify certain pathways to target in protecting against neurotoxic cell damage. Therefore, the purpose of this study was to determine whether one such agent, melatonin (Mel), could confer protection against Oxa-induced neurotoxicity in SH-SY5Y cells. Results from the present study found Oxa to significantly reduce SH-SY5Y cell viability in a dose-dependent manner. Alternatively, we found Mel pre-treatment to SH-SY5Y cells to attenuate Oxa-induced toxicity, resulting in a markedly increased cell viability. Mel exerted its protective effects by regulating reactive oxygen species (ROS) production and reducing superoxide radicals inside Oxa-exposed. In addition, we observed pre-treatment with Mel to rescue Oxa-treated cells by protecting mitochondria. As Oxa-treatment alone decreases mitochondrial membrane potential (Δψm), resulting in an altered Bcl-2/Bax ratio and release of sequestered cytochrome c, so Mel was shown to inhibit these pathways. Mel was also found to inhibit proteolytic activation of caspase 3, inactivation of Poly (ADP Ribose) polymerase, and DNA damage, thereby allowing SH-SY5Y cells to resist apoptotic cell death. Collectively, our results suggest a role for melatonin in reducing Oxa induced neurotoxicity. Further studies exploring melatonin's protective effects may prove successful in eliciting pathways to further alter the neurotoxic pathways of platinum compounds in cancer treatment

Protective effect of Mel on DNA damage induced by Oxa.

<p>Representative images (A) of comet assay on SH-SY5Y cells after exposure to Oxa (50 μM). Oxa incurred DNA damage leading to more number of comet formation compared to Mel pre-treatment cells. DNA damage in cells was quantified as olive tail moment (B) and tail length (C). Significant difference (***P ˂ 0.001) was indicated in comparison to control and significant difference (##P ˂ 0.01) was shown when compared to Oxa treated groups.</p

Protective effect of Mel on Oxa induced cytotoxicity assessed by mitochondrial reduction of MTT to formazan.

<p>Percentage of live cells were calculated and plotted as histogram. Data were represented as mean ± SE (n = 6) Significant difference (*P ˂ 0.05 and ***P ˂ 0.001) was indicated as compared to control and significant difference (#P ˂ 0.05 and ###P ˂ 0.001) was shown with compared to different concentration of Oxa treated groups. Cell viability was measured from at least three independent experiments.</p

Inhibitory effect of Mel on Oxa induced intracellular accumulation of ROS and oxidative stress.

<p>ROS level were monitored by DCFHDA florescent dye. Data were represented as mean ± SE (n = 6) Significant difference (***P ˂ 0.001) was indicated as compared to control and significant difference (###P ˂ 0.001) was shown as compared to Oxa treated groups. ROS measurement was monitored by DCF florescence integrated density. Maximum projections were generated from focus planes and images were displayed with equal pixel intensity. The DCF florescence integrated density was analyzed with Image J software (1.50 version, NIH, USA). ROS accumulation was measured with at least three independent experiments.</p

Protective effect of Mel on Oxa induced intracellular accumulation of superoxide anion and oxidative stress.

<p>Superoxide anion production was monitored by DHE florescent dye. Data were represented as mean ± SE (n = 6) and values were expressed as DHE stained positive cells. Significant difference (***P ˂ 0.001) was indicated as compared to control and significant difference (###P ˂ 0.001) was shown as compared to Oxa treated groups. The DCF fluorescence integrated density was analyzed with Image J software (1.50 version, NIH, USA). Five to six random images were captured at 20x magnification. Maximum projections were generated from focus planes and images were displayed with equal pixel intensity. Superoxide ion accumulation was quantified with at least three independent experiments.</p