Pusat Pengajian Sains Kimia - Tesis

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Docking And Molecular Dynamics Simulation Studies Of Insulin-P- Cyclodextrin Interactions
(2016-02)
Muhammad, Erma Fatiha
Protein-ligand interactions play an essential role in the design of new pharmaceutical products. This study attempts to understand the theoretical basis on the structure and dynamics of insulin-cyclodextrin complex for new oral insulin formulation. Docking and molecular dynamics simulations explore the interactions between insulin monomer and insulin dimer with 0- cyclodextrins (0-CDs). A multiple molecular docking study was performed using the Autodock v4.2 program to determine the number of 0-CD that can adhere to the binding sites of insulin as well as to determine the most stable conformations of insulin to p-CDs. A 100 random structure docking using 1:1 insulin monomer-P-CD and insulin dimer-p-CD ratio were conducted and from the final docked structure, additional 0-CDs were added and the process were repeated until the energy increase. Molecular docking results revealed that a maximum of four 0-CDs can bind to an insulin structure with the 1:3 insulin-P-CD ratios having the lowest binding free energy. A 100 ns molecular dynamics simulation was then conducted to verify the results obtained by molecular docking.
Bis-, Tris-, And Tetrakisbenzimidazolium Salts And Their Silver(I) Complexes: Synthesis, Characterization And Biological Applications
(2024-09)
Abdurrahman, Nuraddeen
This research describes the synthesis, characterization, crystal structure and cytotoxicity activity of several new bis-, tris- and tetrakis-benzimidazolium salts, (1- 24) and their respective silver(I)-benzimidazol-2-ylidene complexes, (Ag1-Ag24). All the compounds synthesized were new based on literature reviewed, it was achieved by changing the either the alkyl or aryl substituents on the benzimidazolium systems and or the bridging ligands related to the previously reported compounds. The salts were synthesized by nucleophilic substitution reaction and were categorized into five series. The salts were 1-5, 6-9, 10-14, 15-19, 20-24 as first, second, third, fourth and fifth series respectively. The synthesized salts were utilized for the synthesis of their respective silver(I)-benzimidazol-2-ylidene complexes, by in-situ deprotonation method in the presence of silver(I)oxide. The cytotoxicity potential of the synthesized compounds was carried out by MTT assay method, in which the breast and cervical cancer cell lines were used. Salt 1-5, 6-9, 15-19, and their silver(I)-benzimidazol-2-ylidene complexes, (Ag1-Ag5, Ag6 -Ag9, Ag15-Ag19) were tested against breast cancer cell lines, while salts, 10-14, 20-24, and their silver(I)-benzimidazol-2-ylidene complexes, (Ag10-Ag14, Ag20-Ag24) were tested against cervical cancer cell lines. The positive control used for the breast cancer cell was tamoxifen and etoposide for the cervical cancer cell. All the salts and their respective silver(I)-benzimidazol-2-ylidene complexes synthesized were characterized using various characterization techniques including FTIR, 1H, 13C NMR, elemental analysis, and single crystal X-ray diffraction method. Physical properties were accessed by melting point analysis, and solubility tests in various organic solvents. From structural elucidation, it was confirmed that Ag2 was dinuclear silver(I)-benzimidazol-2-ylidene complex, with two PF6 anions as counterions balancing the charges of the entire molecule. Complex Ag13 confirmed to be a cylinder-like trinuclear silver(I)-benzimidazol-2-ylidene complex containing three silver(I) ions bridged by two disc-like ligands.
Development Of Fatty Acid-Based Deep Eutectic Solvents In Liquid Phase Microextraction With Back Extraction For Determination Of Selected Organic Pollutants
(2024-04)
Sazali, Nur Hidayah
Environmental pollution has become a significant global issue in recent times. The primary sources of this pollution are human activities such as industrial processes, marine dumping, agricultural practices, and wastewater discharges. Some of the most concerning environmental pollutants are pesticides, herbicides, and polycyclic aromatic hydrocarbons (PAHs) due to their high toxicity and their persistence in the environment. These pollutants have harmful effects on human health and the ecosystem. Due to their high toxicity and trace amount in environment, developing an effective extraction method is essential. Deep eutectic solvent (DES) is a possible green alternative to the conventional solvent utilised in most extraction procedures in light of the increased demand for developing green extraction techniques. Microextraction-based DES fits favourably with the Green Analytical Chemistry (GAC) concept because of its rapid sample preparation time, low organic solvent usage, and straightforward procedure. In this study, an eco-friendly microextraction utilising hydrophobic deep eutectic solvents from fatty acids derived from the combination of lauric acid, which acted as a hydrogen bond acceptor (HBA), and pelargonic acid, which acted as a hydrogen bond donor (HBD), was prepared to determine herbicide mixtures using emulsification liquid-liquid microextraction with back extraction (ELLME-BE) method. In addition, a ferrofluid was developed by incorporating DES, a combination of lauric acid (HBA) and caprylic acid (HBD) with magnetic nanoparticles (MNP) to determine polycyclic aromatic hydrocarbons xxviii (PAHs) using liquid phase microextraction with back extraction (LPME-BE) method. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA),
Bio-Based Graphene From The Oil Palm Empty Fruit Bunches As A Fluid Loss Additive In The Water-Based Drilling Mud
(2024-04)
Safian, Muhammad Taqi-Uddeen
One of the most serious issues encountered during drilling operations is the loss of drilling fluid through the well formation, which is referred to as fluid loss, resulting in dry drilling fluid and increasing the likelihood of the drill being stuck. To prevent this scenario, a fluid loss additive was added to the drilling mud. The effectiveness of bio-based graphene (BG) prepared from oil palm (Elaeis guineensis) empty fruit bunches biomass as a fluid loss additive for water-based drilling mud (WBM) was investigated. To accomplish this, BG was exfoliated from lignin extracted through a soda pulping process. The BG exfoliation process consisted of a combination of thermal treatment via pyrolysis at 300, 600, 800, and 1000 °C with a reaction time of 60 minutes under an argon atmosphere, followed by a mechanical exfoliation using a homogenizer with a shear rate of 12400 rpm for 1 hour. Ultraviolet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) were used to characterize each prepared sample. The Raman analysis confirmed the graphene formation based on the I2D/IG value similar to the commercial graphene, i.e., 0.91. The FTIR analysis revealed that the BG structure has a less functional group than GO, which has been confirmed using XPS as the C/O ratio of BG is less than GO.
Effect Of Multi-Elemental Doping On The Catalytic Activity Of Carbocatalysts For Antibiotics Degradation Via Peroxymonosulfate Activation
(2024-04)
Gasim, Mohamed Faisal Malik
Presently, the utilization of heteroatoms- and/or metal-doped carbocatalysts for the degradation of organic pollutants via catalytic peroxymonosulfate (PMS) activation has drawn significant attention. Yet, there exists a necessity for an in-depth exploration in: (i) understanding the influence of carbonaceous properties on N, S-co-doping, (ii) assessing the effectiveness of heteroatoms tri-doping and apprehending the intra-actions among multiple heteroatoms, and (iii) identifying new transition metals that are suitable for co-doping with N to improve the catalytic activity of carbocatalysts. In view of these research gaps, the main objective of this study is to prepare multi-doped carbocatalysts for PMS activation and unveil the roles of the doped elements in the catalytic activity. Firstly, five N, S-co-doped carbocatalysts were prepared from different carbonaceous precursors, namely sawdust (SD), biochar (BC), carbon-nanotubes (CNTs), graphite (GP), and graphene oxide (GO) and compared. Generally, as the graphitization degree increased, the extent of N and S doping decreased, graphitic N configuration is preferred, and S configuration is unaltered. NS-CNTs illustrated the highest catalytic removal of ciprofloxacin (CIP) under PMS activation (0.037 min−1) due to its remarkable conductivity (3.38 S m−1) and defective sites (ID/IG = 1.28). The PMS activation pathway was dominated by singlet oxygen generation and electron-transfer regime. Secondly, N, S, B-tri-doped biochar was fabricated via a one-pot calcination technique.

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