Approximately 1 in 5 people will develop cancer at some point during their lifetime. As such, the development of effective anticancer treatments is of paramount importance. Unfortunately, current chemotherapeutic methods exhibit high toxicity and limited specificity in differentiating between cancerous cells and normal cells. A promising avenue of research focuses on rationally designing small molecule drugs that can target specific hallmarks of cancer, thus reducing off-target activity within the body. Elevated copper levels have been measured in several cancerous cell lines, such as breast cancer, and this hallmark presents an opportunity for targeted therapeutic intervention through metal chelation. As a result, clear structure-activity relationships (SAR) that enable rational design of metal-chelating small molecule drugs present a promising avenue for addressing these problems. Herein, we report the design and synthesis of a tunable series of tetra-aza pyridinophane derivatives featuring variation in quinoline moiety incorporation and R-group functionalization. These compounds were synthesized and characterized using standard analytical techniques and evaluated for biological activity in cancerous and normal breast cell lines. Overall, this work demonstrates the use of tetra-aza pyridinophanes as a promising platform for the development of selective anticancer agents capable of targeting copper-associated vulnerabilities while minimizing off-target toxicity within the body.

The purpose of the project is to predict the redox potential of tetra-aza macrocycle copper complexes. Density functional theory combined with a continuum solvation model was used to compute the redox potentials of 23 copper–ligand complexes. Gibbs free energies for the redox reactions were evaluated at the M06-2X/Def2-SVP/Def2-TZVPP/SMD level of theory. The predicted redox potentials agree well with experimental values for tetra-aza macrocyclic copper complexes. To examine the influence of chloride, calculations were performed for ligand systems both in the presence and absence of coordinated Cl. The correlation between the computed and experimental measurements yielded R2 values of 0.92 (without coordinated Cl) and 0.89 (with coordinated Cl), reflecting trends consistent with experimental measurements. For the complexes without coordinated chloride, the predictions further demonstrated strong accuracy, with a root-mean-square error of 30.9 mV. Overall, the result highlights this computational workflow as a practical approach for estimating the redox properties of copper complexes, redox-active systems relevant to biomimetic and medicinal chemistry.

Salt-induced diffusiophoresis is the migration of a charged nanoparticle in water, induced by an imposed directional gradient of salt concentration. This transport phenomenon has emerged as a valuable tool for particle manipulation inside porous materials and microfluidics. Micelles are a common example of nanoparticles with the crucial ability of hosting small guest molecules. Thus, micelle diffusiophoresis is important in the manipulation of small molecules. Diffusiophoresis depends on the intrinsic ability of micelles to randomly move (diffuse) in water. In this poster, we report experimental micelle diffusion coefficients for the surfactant hexadecylpyridinium chloride (CPC) in the presence of aqueous NaCl and KCl. The electrical double layer theory was successfully employed to explain the effect of surfactant and salt concentrations on the observed micelle diffusion coefficient. These data were then used to characterize salt-induced diffusiophoresis of charged micelles.

Influence of a NiO Hole Transport Layer on Charge Separation in FTO|WO₃|BiVO₄ Photoanodes for TEMPO-Mediated Oxidation

Favor Igwilo, Texas Christian University, Class of 2026
Laboratory of Dr. Benjamin Sherman, PhD;
Department of Chemistry and Biochemistry

Efficient hole transport is critical for driving oxidative transformations in photoelectrochemical systems. In this study, we investigate multilayer FTO|WO₃|BiVO₄|NiO photoanodes for application in TEMPO-mediated oxidation of benzyl alcohol to benzaldehyde, an important chemical reaction used in industrial processes. The stable radical 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) enables selective alcohol oxidation under mild conditions and represents a more sustainable alternative to conventional stoichiometric oxidants that generate hazardous waste. Enhancing interfacial charge transport is essential to improve the viability of this photoelectrosynthetic process.

We hypothesize that nickel oxide (NiO), a p-type semiconductor, can function as an effective hole transport layer due to its favorable valence band alignment, hole mobility, abundance, and low cost relative to traditional materials such as titanium dioxide (TiO₂). A liquid phase deposition protocol was developed to fabricate uniform NiO thin films on fluorine-doped tin oxide substrates, which were subsequently integrated into FTO|WO₃|BiVO₄ substrates. The resulting multilayer photoanodes were evaluated to determine whether NiO enhances charge separation and hole extraction under various conditions.

Electrochemical characterization was performed using cyclic voltammetry to probe redox behavior and assess catalytic onset potentials, chronoamperometry to quantify steady-state photocurrent and operational stability, and electrochemical impedance spectroscopy to evaluate interfacial charge transfer resistance. Measurements were conducted under both dark and illuminated conditions, with and without TEMPO, in Tetrabutylammonium hexafluorophosphate (TBAPF6)in acetonitrile (ACN) solution. We anticipate that incorporation of NiO will reduce interfacial charge transfer resistance, increase photocurrent density in the presence of TEMPO, and improve kinetic parameters associated with benzyl alcohol oxidation.
Photocurrent densities of FTO|WO₃|BiVO₄ and FTO|WO₃|BiVO₄|NiO photoanodes were directly compared to quantify the effect of the NiO interlayer. Additionally, heterogeneous electron transfer rate constants (k₀) were determined under TEMPO-containing conditions to assess how the multilayer structure influences interfacial electron transfer kinetics.

This work establishes a working protocol for NiO liquid phase deposition and clarifies the role of NiO in enhancing TEMPO-mediated photoelectrosynthetic oxidation. These findings can later inform the design of cost-effective photoelectrode architectures for sustainable organic reactions.

By combining the supportive structure of alginate hydrogels, the semiconductive nature of porous silicon (pSi) membranes, and the biodegradability of both of these materials, a unique, non-invasive biosensor can ideally be created for the chemical analysis of health-relevant analytes.
Hydrogels are water-infused, biodegradable polymer networks that are easily able to interface with human skin. Alginate polymer hydrogels are particularly useful due to being derived from brown algae, making them environmentally abundant and inexpensive. The polymer is modified with acrylamide segments to add stability and shelf-life to the hydrogel material. Ultimately, these characteristics make hydrogels ideal for supporting the pSi membranes while assimilating them to a variety of tissues.
Porous silicon (pSi) is a highly porous form of the widely used elemental semiconductor and is used to conduct and measure electrical signals throughout the hydrogel matrix. When established in a diode form, these membranes exhibit measurable current values as a function of voltage, which can be used to detect bioelectrical stimuli such as the concentration of physiologically relevant ionic species such as Na+, K+, and Ca2+.
Recent experiments focus on integrating pSi membranes in Acrylamide/alginate co-polymer hydrogels to test how variations in ion concentration affect the flow of current measured as a function of applied voltage. Porous silicon membranes ~110 μm thick and 79% porosity, are fabricated from the anodization of low resistivity (100) Si in methanolic HF at an applied bias of 100 mA/cm2 for 30 minutes. Membranes pieces ~2 mm by 2 mm are heated for one hour at 650°C. They are then affixed to Cu wire using Ag epoxy and annealed for 15 minutes at 95°C. The wires are then fashioned to form the membrane diodes and clear nail polish is used to coat the backs of the membranes, the Cu wire connection, and the wire itself to prevent current flow from the back of the membrane or bubble formation. The electrochemical cell is created by placing two pSi membranes parallel to each other ~2 mm apart, vertically, in a fixed electrolyte composition. The current is measured as function of applied voltage (typically from 0-5 V) for systems with different concentrations of NaCl in the nM to mM range. The NaCl solutions are injected directly into the hydrogel in between the two pSi membranes in 2 μL units.
This presentation will focus on the fabrication protocol, as well as results from experiments with varying NaCl concentrations. Previous experiments have determined linearity of the current and applied voltage function in the region of 0.25 mM to 1 mM concentration ranges of pure NaCl solution. Future experiments will seek to repeat these findings within the alginate hydrogel matrix.