Department of Chemistry

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Author: search.filters.author.Dr. Muhammad Nasir

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    Early and Rapid Detection of Methyl Nicotinate for Tuberculosis Control, Progression and Monitoring using Cobalt Doped Graphitic-Carbon Nitride
    (Library Information Services COMSATS University Islamabad Lahore Campus, 2023-02-27) Sundas Abid; SP22-R06-016; Dr. Muhammad Nasir; LHR TP 8655
    Mycobacterium tuberculosis (Mtb) caused tuberculosis (TB) is the most prevalent infectious agent-related cause of death, accounting for around 1.8 million deaths per year. This emphasises the importance of tuberculosis as a global public health concern. It is estimated that one-third of the world's population has latent Mtb, and 10% of those individuals will eventually develop health problems. Our strategy is to develop an affordable test based on nanomaterials that can detect the early signs of tuberculosis by looking for volatile markers of the disease. Sensors are crucial tools for the early identification of illnesses and for tracking such conditions while they are being treated. To overcome the time taking tuberculosis detection methods the current research developed a cobalt doped graphitic carbon nitride (Co-gCN) fluorescence sensor that has high selectivity and sensitivity towards Methyl nicotinate (MN) a volatile biomarker of TB. Graphitic carbon nitride (g-CN) as a fluorescence sensor has gained significant attention due to its remarkable optical, electrical, and sensing properties. Because of this exceptional catalytic activity, we were able to develop a fluorescence sensing technique quickly and easily for the detection of Methyl nicotinate. The designed sensor demonstrated a linear range of 0.25μM −7μM (R2 = 0.9992) with a limit of detection of 0.0581 μM for the detection of Methyl nicotinate. Since tuberculosis is asymptomatic when it is latent. Tests for enzyme-based detection, such PCR and ELISA, take a long time and have a limited sensitivity of detection. Therefore, novel cobalt doped graphitic carbon nitride nanocomposite synthesized using one-pot thermal condensation method. SEM, XRD, FTIR, UV-Vis and fluorescence spectrophotometry were used to justify the morphology, surface chemistry, chemical content, and fluorescence behavior of the synthesized nanocomposite. With benefits over existing techniques the developed sensor has a great deal of promise and is a good fit for enzyme mimicking detection of MN for early detection of TB.
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    Designing of Modified Cerium Oxide-Based Enzyme Mimic Nanomaterials as Optical Sensors for the Sensitive and Selective Detection of Hydrogen Peroxide
    (Library Information Services COMSATS University Islamabad Lahore Campus, 2021-02-24) Aaiza Ramzan; FA19-R06-024; Dr. Muhammad Nasir; LHR TP 7338
    Imbalance in the amount of biological substances like hydrogen peroxide is the key reason behind different ailments and cell damage. Different approaches have been developed for the detection of hydrogen peroxide. However, they have many drawbacks, such as high cost of the substrates, expensive instruments which require trained personnel to handle and low sensitivity and selectivity. Therefore, to overcome mentioned limitations we devised a sensor-based system which is facile, easy to handle and less expensive. Nanorods comprising of cerium oxide doped iron and cobalt with variable concentrations were synthesized using hydrothermal method. To study its properties various characterization techniques were used such as FTIR analysis for the confirmation of different functional groups in the composite (Fe3+-Co2+-CeO2), XRD studies to study the crystallite size and growth of iron and cobalt inside the cerium oxide lattice of the prepared composites. SEM analysis was performed to check the surface morphology and the grain size of the synthesized samples. As a proof of the concept studies these prepared nanocomposites were used for the detection of hydrogen peroxide. Before using these nanocomposites for the detection, concentrations of different parameters were optimized, such as buffer amount and pH, incubation time, temperature and TMB (3, 3', 5, 5'-Tetramethyl-benzidine) amount etc. which have lot of impact on the sensor properties and its activity. TMB was used as a chromogenic substrate for colorimetric analysis of the prepared sample. The nanocomposite (Fe3+-Co2+-CeO2) helped in decomposition of hydrogen peroxide in its radicals and these radicals oxidized TMB in the reaction mixture which led to color change as a result. This change in color is the indication of amount of hydrogen peroxide present in the system, the more the color change the more the amount of hydrogen peroxide and vice versa. UV-Vis spectroscopy was used for measuring the absorbance of different percentages. The limit of detection (LOD) estimated using the data obtained under optimal conditions and within a linear range of 0.1 μm-20mM (R2=0.9402) was found to be as low as 0.057 μm. The selectivity of the platform was confirmed by the study of certain interfering species. The results confirmed the sensitivity of this colorimetric sensor for the detection of hydrogen peroxide.