Browsing by Author "Dr. Akhtar Hayat"

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    Electro-Opto Multi-Functional Imprinted Pencil Graphite Sensor for Monitoring of Gemcitabine
    (Library Information Services COMSATS University Islamabad Lahore Campus, 2023-02-26) Shaista Ijaz Khan; FA21-R06-020; Dr. Akhtar Hayat; LHR TP 8450
    In both research laboratories and. hospitals, there is a high demand for the development of quick, easy to uses and simple procedures for gemcitabine, monitoring in biological samples and pharmaceutical formulation. This study reports the simplest, quick, and direct electro-opto method for gemcitabine monitoring using a molecularly imprinted pencil graphite electrode. An electro-optical multifunctional nanoprobe (BSA /Ag NPs) was used to give electrochemical as well as optical signal for GMT monitoring. Then, electrochemical polymerization was used to create an MIP network in situ, GMT used as template and pyrrole as monomer. Differential pulse voltammetry (DPV) investigation revealed that when GMT concentration increases, the peak signal of Ag oxidation also increases. whereas UV-visible spectrum shows with increase in GMT concentration the optical response of nanoprobe decreased. The results of DFT simulations depict the gemcitabine interacted polypyrrole (PPy) complexes have sufficient adsorption energies (-7.67 to -10.42 kcal/mol) and are thermodynamically stable. A reduction in HOMO-LUMO energy gaps (2.27-2.45 eV) is observed with remarkable electrical conductivity than pristine polypyrrole (3.66 eV). The analyses of other reactivity parameters and molecular electrostatic potential suggest that drug delivery properties of polypyrrole have been enhanced. Furthermore, molecular docking results of gemcitabine against the bovine serum albumin (BSA=3V03) reflect that gemcitabine interacted BSA complex has remarkable docking energies (-5.8 to -6.7 kcal/mol) and can exhibit biological activity. This method enabled the measurement of GMT to cover the range from 5 to 200 μM in addition to a remarkably low detection limit of 3.6 μM. Additionally, when monitoring GMT for a period of 6 weeks, the sensor showed great repeatability, reusability, anti-interference capability, and maintained excellent stability. The proposed sensor ultimately demonstrated
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    Fabrication of Electro-active Nano-trans Surfaces to Design Label Free Aptasensor for Ochratoxin-A Detection
    (Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-17) MAHAM LIAQAT; FA18-R06-004; Dr. Akhtar Hayat; LHR TP 5961
    With increased awareness of nutrition and the advocacy for healthier food choices, there exists a great demand for a simple, low-cost, label free and easy-to-use assays that can reliably detect toxins in agriculture products. In this regard, a simple and highly sensitive electrochemical sensing platform based on the structural switching signaling of aptamer has been developed for the detection of smaller molecules using Ochratoxin A as a model analyte. Pencil electrode was first modified with highly conductive Graphene oxide/Fe3O4NP/PPY composite and then was self-assembled with aptamer using EDC/NHS technique. This immobilized nanoprobe provided gates of tunnels for the effective electron flow showing higher peak current. The introduction of the target analyte (OTA) triggered switching of the aptameric structure resulting in the decrement of the redox current. This decrease was proportional to the analyte concentration, thus featuring signal on/off strategy. This proposed transducing design showed a dynamic linear range (10 pg/mL-200ng/mL) with Limit of detection and limit of quantification of 5pg/mL and 40pg/mL respectively. We demonstrate this transducing design as a general inexpensive and reproducible method to specifically detect a wide variety of analytes by selecting a suitable biorecognation element. Real sample analysis was performed for the real time approach and results collected are in agreement with practical application.