Browsing by Author "Khan, Muhammad Salman"

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Open Access
Design and simulation of microfluidic device for metabolite screening and quantitative monitoring of drug uptake in cancer cells
(Sciendo, 2018) Asif, Afia; Khawaldeh, S.; Khan, Muhammad Salman; Tekin, Ahmet; Electrical & Electronics Engineering; TEKİN, Ahmet; Asif, Afia; Khan, Muhammad Salman
Although liquid-liquid extraction methods are currently being applied in many areas such as analytical chemistry, biochemical engineering, biochemistry, and biological applications, accessibility and usability of microfluidics in practical daily life fields are still bounded. Suspended microfluidic devices have the potential to lessen the obstacles, but the absence of robust design rules have hampered their usage. The primary objective of this work is to design and fabricate a microfluidic device to quantitatively monitor the drug uptake of cancer cells. Liquid-liquid extraction is used to quantify the drug uptake. In this research work, designs and simulations of two different microfluidic devices for carrying out multiplex solution experiments are proposed to test their efficiency. These simplified miniaturized chips would serve as suspended microfluidic metabolites extraction platform as it allows extracting the metabolites produced from the cancer cells as a result of applying a specific drug type for a certain period of time. These devices would be fabricated by making polydimethylsiloxane (PDMS) molds from the negative master mold using soft lithography. Furthermore, it can leverage to provide versatile functionalities like high throughput screening, cancer cell invasions, protein purification, and small molecules extractions. As per previous studies, PDMS has been depicting better stability with various solvents and has proved to be a reliable and cost effective material to be used for fabrication, though the sensitivity of the chip would be analyzed by cross contamination and of solvents within the channels of device.
Metadata only
Dopamine detection using mercaptopropionic acid and cysteamine for electrodes surface modiﬁcation
(2017-05) Khan, Muhammad Salman; Tekin, Ahmet; Tekin, Ahmet; Yaralıoğlu, Göksenin; Skarlatos, Y.; Department of Electrical and Electronics Engineering; Khan, Muhammad Salman
This research work emphasizes on main objective of dopamine detection using electrochemical detection analysis. Dopamine is an electrochemical neurotransmittor and is an essential part in human body for many decisions. It can also be described as a chemical released by neurons (nerve cells) to send signals to other nerve cells. The interest in dopamine was stimulated due to several physiological and neurological diseases such as Parkinson's disease, schizophrenia, obsessive compulsive disorder and many drug addictions. Gold electrodes are often not suitable for the dopamine measurements as dopamine creates a non conducting polymer layer on the surface of the electrodes, which leads to the increased amount of electrode passivity with the gradual increase in voltammograms measurement. This work is presented to contribute in a better understanding on the comparative study of targeted dopamine detection with two surface modiﬁcations for Au electrodes with mercaptopropionic acid (MPA) and cysteamine. The results are further characterized with the impedance spectroscopy (EIS) and cyclic-voltammetry (CV) for providing a comparison of dopamine detection for thermally bonded and ultrasonically welded microﬂuidic chips respectively. Moreover, the effects of selecting optimized tubing, bonding techniques, and cleaning methods of the devices with KOH solution played crucial role for improvements in dopamine detection which are observed in results. Also a comparison for the modiﬁcation with unmodiﬁed chips, and ﬁnding the unknown concentration of dopamine solution using ﬂow injection techniques has also been illustrated.
Open Access
Dopamine detection using mercaptopropionic acid and cysteamine for electrodes surface modification
(Sciendo, 2018) Khan, Muhammad Salman; Asif, Afia; Khawaldeh, S.; Tekin, Ahmet; Electrical & Electronics Engineering; TEKİN, Ahmet; Khan, Muhammad Salman; Asif, Afia
Gold electrodes are often not suitable for dopamine measurements as dopamine creates a non-conducting polymer layer on the surface of the electrodes, which leads to increased amount of electrode passivity with the gradual increase in voltammograms measurement. This work presents the impedance spectroscopy and cyclic-voltammetry comparative study for dopamine detection with two modifications for the surface of Au electrodes; cysteamine and mercaptopropionic acid for thermally bonded and ultrasonically welded microfluidic chips, respectively. The effects of optimized tubing selection, bonding techniques, and cleaning methods of the devices with KOH solution played crucial role for improvements in dopamine detection, which are observed in the results. Furthermore, comparison for the modification with unmodified chips, and finding the unknown concentration of dopamine solution using flow injection techniques, is also illustrated.