Academic
http://hdl.handle.net/10576/22
2024-03-19T12:15:45ZMicrofluidic devices with modified electrochemical detection for biomarkers analysis: A review
http://hdl.handle.net/10576/53231
Microfluidic devices with modified electrochemical detection for biomarkers analysis: A review
Bani-Yaseen, Abdulilah Dawoud; Parker-James, Samantha; Sellens, Kathleen; Culbertson, Christopher T.; Jankowiak, Ryszard
Integrated microfluidic systems continue to garner a great deal of attention. This interest can be attributed to the advantages that these microsystems exhibit over conventional separation and detection systems while performing biomedical and biochemical analyses. Over the past several years many research groups have demonstrated that microfluidic devices with incorporated microelectrodes can be utilized for a broad range of applications. In this work, we review recent developments in the use of microfluidics for the analysis of various types of potential biomarkers. Since microelectrodes usually imply electrochemical sensing, we will focus on microfluidic devices with modified electrochemical detection. Particularly, we describe the principle of operation of these microdevices with an emphasis on recent efforts to improve the sensitivity and selectivity of these microfluidic devices interfaced with electrochemical detection. We describe the various configurations of the microdevices with emphasis on the microelectrode fabrication, modification, and mode of operation. In addition, the potential applicability of these microsystems with integrated microelectrodes for biomarker discovery and analysis is discussed.
2014-01-01T00:00:00ZComputational study on the nanotubes formation between olsalazine and β-cyclodextrin
http://hdl.handle.net/10576/53230
Computational study on the nanotubes formation between olsalazine and β-cyclodextrin
Bani-Yaseen, Abdulilah Dawoud
Interests in cyclodextrin-derived nano-assembled supramolecular systems have recently grown notably [1,2].
Cyclodextrins are a family of oligosaccharides that possess very characteristic features of conical shape with hydrophobic and hydrophilic interiors and exteriors, respectively. As a host molecule, cyclodextrin (CD) can encapsulate various types of molecules inside its cavity as host-guest supramolecular interaction that is in turn stabilized by non-covalent interactions [3-5]. Under specific conditions, cyclodextrins can self-aggregate to form nanoarchitectures, such as nanotubes and nanorods. However, guest-induced nanotubular architecture can be assembled with gust molecules of suitable size, such as olsalazine drug. The objective of this work is to computationally investigate the formation and the corresponding molecular properties of olsalazine--CD nanotubes using the semi-empirical method (SQM) PM7. Different guest:host ratios of inclusion complexes that can lead to the formation of the olsalazine--CD nanotubes were examined, namely 1:2 and 2:2. Furthermore, the side of penetration of the guest molecule is another factor that is considered herein, where head and tail inclusions correspond to the penetration inside the cavity of -CD through the wide and narrow rims of -CD, respectively. On the other hand, the head-to-head, tail-to-tail, head-to-tail aggregations of -CD nanotubes are considered.
2017-04-01T00:00:00ZSynchronous spectrofluorimetric study of the supramolecular host–guest interaction of β-cyclodextrin with propranolol: A comparative study
http://hdl.handle.net/10576/53229
Synchronous spectrofluorimetric study of the supramolecular host–guest interaction of β-cyclodextrin with propranolol: A comparative study
Abdulilah Dawoud, Bani-Yaseen
The objective of this work is to assess the use of constant-wavelength synchronous fluorescence spectroscopy (SFS) in comparison to conventional fluorescence spectroscopy (CFS) for the investigation of the supramolecular host–guest interaction of β-CD with propranolol (PPL) in aqueous solutions. Scanning for the optimal Δλ at which the SFS can be performed in the presence of β-CD was examined. The results obtained revealed three distinguishable shapes for PPL using SFS that can be represented by three different Δλ values, namely 10, 40, and 100nm. However, the effect of the β-CD concentration on the fluorescence intensity of PPL was examined using CFS and SFS of PPL at a Δλ of 10 and 100nm. The change in the fluorescence intensity was used to calculate the equilibrium constant (Keq) for the formation of the β-CD:PPL inclusion complex by applying the Benesi–Hildebrand method. Keq values of 108, 112, and 117M−1 were obtained using SFS with a Δλ of 10 and 100nm, and CFS, respectively. Further, the SFS method was successfully employed to examine the iodide quenching effect on the fluorescence intensity of PPL, where the results obtained revealed a Stern–Volmer quenching constant of 42.8M−1, which is in good agreement with results obtained using CFS. All results obtained using the SFS method were compared with the results obtained using the CFS method.
2015-04-07T00:00:00ZComputational Insights on the Electrocatalytic Behavior of [Cp*Rh] Molecular Catalysts Immobilized on Graphene for Heterogeneous Hydrogen Evolution Reaction
http://hdl.handle.net/10576/53228
Computational Insights on the Electrocatalytic Behavior of [Cp*Rh] Molecular Catalysts Immobilized on Graphene for Heterogeneous Hydrogen Evolution Reaction
Bani-Yaseen, Abdulilah Dawoud; Elbashier, Elkhansa
The heterogeneous metal-based molecular electrocatalyst can typically exhibit attractive features compared to its homogeneous analogue including recoverability and durability. As such, it is necessary to evaluate the electrocatalytic behavior of heterogenized molecular catalysts of interest toward gaining insights concerning the retainability of such behaviors while benefiting from heterogenization. In this work, we examined computationally the electrochemical properties of nanographene-based heterogenized molecular complexes of Rhodium. We assessed, as well, the electrocatalytic behavior of the heterogenized molecular catalyst for hydrogen evolution reaction (HER). Two electrochemical pathways were examined, namely one- and two-electron electrochemical reduction pathways. Interestingly, it is computationally demonstrated that [RhIII(Cp*)(phen)Cl]+-Gr can exhibit redox and electrocatalytic properties for HER that are comparable to its homogeneous analogue via a two-electron reduction pathway. On the other hand, the one-electron reduction pathway is notably found to be less favorable kinetically and thermodynamically. Furthermore, molecular insights are provided with respect to the HER employing molecular orbitals analyses and mechanistic aspects. Importantly, our findings may provide insights toward designing more efficient graphene-based molecular heterogeneous electrocatalysts for more efficient energy production.
2020-04-01T00:00:00Z