Department of Chemistry
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Item Synthesis and Characterization of Injectable, Biocompatible and Biodegradable Hydrogels for Biomedical Application(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-26) Muhammad Shumail; FA20-R06-013; Dr. Asma Tufail Shah; LHR TP 7883Periodontitis is a common oral infection that affects about 10-15% of global population. Periodontitis is characterized by gum inflammation, gingival recession, tissue loss, and dental pocket formation. Different approaches like tooth scaling, ultrasonic scalars, lasers, and root planning as well as surgical procedures have been employed but these mechanical treatments are limited and invasive. For tissue repair or wound healing, it is important to develop biomaterials which have ability of regeneration of bone tissues along with antibacterial properties and would be less invasive in nature. Injectable hydrogels are crucial in this area because they have mechanical and structural characteristics comparable to many body tissues and the artificial extracellular matrix (ECM) and can be delivered to the body in the least invasive manner. In this study a novel thermosensitive, injectable, biocompatible, and biodegradable Chitosan-Alginate based hydrogel was synthesized in combination with bioactive glasses. Different concentrations of primary polymers and copper substituted bioactive glasses were studied and characterized by employing various analytical techniques including XRD, FTIR, Contact Angle, Zetasizer and Inverted microscope. Gelation effect and setting time of these hydrogels were analyzed with and without Bioactive glass. The injectability of these biomaterials was tested via syringe needles of various gauges. Bioactivity and degradability studies were performed along with antibacterial applications against E. coli and S. aureus in which the hydrogels with copper substituted bioactive glass demonstrated positive anti-bacterial activity.Item Hydrogen Splitting Using Single Metal Atom Doped C3N Nanosheet as a Catalyst: A DFT Study(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-26) Zulqarnain Haider; FA20-R06-010; Dr. Mazhar Amjad Gilani; LHR TP 7881Atomic hydrogen is the most intriguing free radical for high-energy applications. The ability of atomic hydrogen to protect DNA and mitochondria from oxidative damage may be advantageous in the treatment of chronic illnesses including cancer. When dissociation energy is supplied, a molecule of hydrogen dissociates into two atoms (H2 → 2H). In contrast to other radicals, hydrogen recombination requires no activation energy. The highest efficiency and stability for heterogeneous catalysis of hydrogen splitting are provided by single-atom catalysts adsorbed on the active surface. For support of single-atom catalyst (SAC), carbon nanotubes, graphene, metal hydrides, metal-organic frameworks, graphene, graphdiyne, carbon nitride, and silanes surfaces have been employed recently. The presence of nitrogen in carbon nitride surfaces is shown to be much more effective for hydrogen dissociation and considered as the most suitable substrate for SAC. Because of their varying oxidation states, transition metals have several spin states that can be tested, and the most stable spin states based on thermodynamic energy data may be determined. The optimized C3N nanosheet is doped with 3d transition metals. The lowest energy spin state of each doped metal is considered for further calculations. The stabilities of complexes have been measured by calculating the interaction energies of optimized geometries. Adsorption energies of H2 on metal doped carbon nitride surface are computed to investigate the adsorption mechanism and characterize the energetic heterogeneity of solid surfaces. The energy barrier (activation energy) and reaction energies are required to determine the splitting of hydrogen. This study shows that SAC can be used as the most efficient doping technique for hydrogen splitting.Item Antibacterial dual cross-linked hydrogels for Periodontal Regeneration(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-26) Fakhira Bashir; FA20-R06-004; Dr. Sobia Tabassum; LHR TP 7878Periodontitis is one of the most common gum diseases caused by bacterial infection. It affects teeth's surrounding bone and tissues. It is important to treat the disease promptly as it not only results in tooth loss but also affects the general health of the patient. It is extremely common in young individuals with occurrence rates of approximately 50% across the world. Different graft materials are used to treat periodontal defects, but unpredictable clinical outcomes of existing solutions encourage developing novel materials with enhanced functionality. This study aimed to formulate oval proteins, hydroxyapatite (HA) and PVA based anti-bacterial dual cross-linked hydrogels for periodontal regeneration. Potential non-toxic and biodegradable oxidized alginate, borax and divalent ionic (Cu+2, Zn+2, Ca+2) solutions were used as cross linking agents. Oval proteins act as efficient gelling agent and can mimic the ECM microenvironment. Hydrophilicity, potential bio-degradation, outstanding cytocompatibility, less cytotoxicity, surface alignment features, and self-healing are some of distinctive properties of prepared hydrogels. Hydroxyapatite (HA) is a bio-ceramic and used as bone regeneration material.Item A Theoretical Exploration of Supramolecular Architectures as High Performance Nonlinear Optical (NLO) Materials(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-26) FA20-R06-001; Aqsa Nisar; Dr. Mazhar Amjad Gilani; LHR TP 7876Density functional theory (DFT) calculations have been performed for a series of supramolecular assemblies containing azobenzene (Azo-X where X=I, Br and H) and alkoxystilbazole subunits to evaluate their electronic, linear and nonlinear optical properties. These assemblies are derivatives of azobenzene, obtained by the substitution of electron-withdrawing and electron-donating groups onto the molecular skeleton. The interaction energies (Eint) of all the designed supramolecular complexes (IA-IF, IIA-IIF and IIIA-IIIF) range from -1.02 kcal/mol to -7.70 kcal/mol. Electronic properties of these hydrogen/halogen bond driven supramolecular assemblies such as, vertical ionization energies (VIE), HOMO-LUMO energy gap (GH-L), excitation energies, density of states (DOS) and natural bond orbital (NBO) analyses were also computed. The non-covalent interaction index (NCI) and quantum theory of atoms in molecules (QTAIM) analyses have also been performed to validate the nature of inter- and intra-molecular interactions in these complexes. A substantial enhancement in the first hyperpolarizability (βₒ) values of the designed supramolecular complexes has been observed driven by the charge transfer from the pyridyl moiety of alkoxystilbazole to Azo-X. The highest first hyperpolarizability (βₒ) value of 1.3×104 au is observed for supramolecular complex of p-nitro substituted azobenzene with alkoxystilbazole (ID complex). It was confirmed on a purely theoretical basis that both the type of noncovalent interactions present and the substituent group incorporated influence the nonlinear optical response (NLO) of the systems.Item Determination and Detoxification of Aflatoxins in Food and Animal Feed(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-26) Muhammad Zain-ul-Hassan; FA20-R06-009; Dr. Muhammad Javid Iqbal; LHR TP 7880Aflatoxins are secondary metabolites produced by fungi that cause food contamination, sickness, and have a significant impact on both animal and human health. Aspergillus species create aflatoxins, which are dangerous mycotoxins. The purpose of this study was to determine the amounts of aflatoxins in food and animal feed samples. A total of 30 food samples including (White rice, Brown rice, Pistachio, Almonds, Peanuts) and 30 Broiler feed samples including (Starter, Grower, Finisher) were gathered from food and broiler farms. Contamination was discovered in 44 samples using the Thin Liquid Chromatography (TLC) method and Enzyme-linked Immunosorbent Assay (ELISA), with 10 (33%) being contaminated beyond the allowed level and 14 (47%) being contaminated within the permissible range. The reduction in Aflatoxins level both in food and animal feed samples was observed by using different physical methods including heating which showed about 88% degradation of Aflatoxins in food samples and about 65.8% in animal feed samples, Gamma radiations up to 10kGy showed degradation up to 45% in food and 51% in feed samples and chemical method showed 96.6% degradation of Aflatoxins in food samples and 95.5% degradation in animal feed samples by applying ammonia concentration up to 2%. This study found that food and broiler feed samples taken from different farms were contaminated, possibly due to poor food and feed storage conditions. It is suggested that authorities require improved storage conditions and regular monitoring in order to decrease aflatoxins contamination.Item Hydrothermal Synthesis of Silver & Zinc Doped Bioactive Coatings on Magnesium Alloy for Potential Application in Orthopedics(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-25) Kinza Mujahid; FA20-R06-008; Dr. Eng. Farasat Iqbal; LHR TP 7879Biomaterials are artificially designed implants used in various medical applications such as orthopedic, cardiovascular and dental implants in past. These metallic implants have been selected based on biocompatibility, mechanical strength and bioresorbability to fix the bone fracture. Conventional implants i.e., Titanium, stainless steel and cobalt alloy have been implanted as bone fixation devices that needs revised surgery to remove them once the bone healed. So, they are health costly as well as cause financial burden on patients. Therefore, biodegradable and biocompatible permanent implants are required, which degrade slowly with healing process and maintain its mechanical integrity until new bone is regenerated. The ideal candidate for this is Mg and its alloys that can be used in orthopedic devices. Mg and its alloys fulfill the criterial of biocompatibility, osteogenetic ability, appropriate mechanical strength, and low elastic modulus (~40 GPa) which is close to human bone (~20 GPa). Its fast degradation rate results into release of hydrogen gas at surgery site and loss of its mechanical strength and attack of bacteria are the major challenges in orthopedic application.Item Biodiesel production through microbubble mediated mass transfer using zwitterion catalysts(Library Information Services COMSATS University Islamabad Lahore Campus, 2022-02-25) Maryam Asif; FA20-R06-012; Dr. Fahad Rehman; LHR TP 7882The total energy consumption is increased due to the rapid expansion of industries and metropolitan development. Biodiesel is a substitute fuel to conventional diesel, which is non-carcinogenic, sustainable, and has a high cetane number. The conventional methods used for biodiesel synthesis are energy-intensive, and operational cost is high. Catalytic esterification and transesterification methods are employ for the cleaner production of biodiesel. Due to the presence of high content of free fatty acid (FFA), transesterification carries the drawback of sponification. In the esterification reaction, FFA was reduced using an acidic catalyst. However, thermodynamic equilibrium restricts the overall conversion and slows the pace of the reaction—the current study used microbubble-mediated mass transfer technology to overcome this problem. Acid catalysts are used for esterification, show good activity, and produce high-quality biodiesel. Although the rate of the reaction is slower, it takes longer and at a higher temperature to achieve the maximal conversion. Various basic catalysts have been used for biodiesel synthesis to overcome the acid catalysts' drawbacks. Under mild conditions, show high catalytic activity in the transesterification process. However, base catalysts are limited due to high water affinity and moisture during storage. Saponification is another disadvantageous feature of these catalysts. Esterification and transesterification could both be performed by a catalyst that has both acidic and basic sites. This study aims to propose a sustainable strategy to energy generation using microbubble technology and bi-functional catalyst. As a heterogeneous catalyst for the generation of biodiesel, strontium zirconium oxide (7% Sr/ZrO2) was produced, and compared with naturally occurring bi-functional catalysts such as zwitterions is also used to investigate biodiesel production. To optimize the synthetic bifunctional catalyst response surface methodology (RSM) was used.