Senuri Jayawardana Arachchige, Ella Madura, Víctor García-López

Metal-organic cages offer a powerful platform to study the effects of nanoconfinement on high-energy intermediates such as triplet excited states. Here, we present a design strategy for molecular cages that not only provide confinement but also act as photosensitizers, enabling indirect excitation of guest molecules under visible light. Our cages feature thioxanthone (THX) coordinated with earth-abundant Zn(II) and Fe(II), providing a sustainable alternative to conventional cages that rely on rare metals like Pd, Pt, Ru, and Ir. THX is chosen for its high triplet energy (ET*: 65.5 kcal mol- ) and long triplet lifetimes (τ0: 77 μs), with the added advantage of visible light absorption, which is not the case of other aromatic ketones.

We synthesized THX-based ligands with varying lengths, geometries, and chelating units (imino-pyridine, 2,2’-bipyridine, 2-pyridyl-1,2,3-triazole) and evaluated their self-assembly into cages under different conditions. Computational studies provided insight into how linker distortion and metal-ligand interactions influence cage stability. Understanding and tuning triplet states through supramolecular design could advance photocatalysis, optoelectronics, light-emitting diodes, imaging agents, and sensors.

Jullyane Matsushima, Alexanndra M Behm, Mario E Rivera, Víctor García-López

Bacteria is a growing threat to human life, leading to a need for the development of better tools to study and understand their proliferation mechanisms, antibiotic resistance, and other functions. Contrary to previous beliefs, bacteria can change their membrane potential. This enables them to regulate physiological processes and behaviors, which is crucial for their survival and proliferation. Bacterial membrane potential dynamics are yet not fully understood, mainly due to the lack of non-invasive and high throughput techniques to study their electrophysiology. Optical methods based on fluorescence microscopy are an alternative, but their efficiency is limited by the available probes. The most common probes usually present a low permeability in gram-negative bacteria, are unsuitable for fast dynamics, and are used in high concentrations, which could disrupt the membrane potential. To address these limitations, we aim to develop molecular probes based on diarylethene photoswitches enabling them to be optically turned on/off with spatiotemporal precision, and with the ability to report and quantify changes in the membrane potential by changing their fluorescence lifetime. This will help avoid problems such as uneven dye loading, bleaching, and variation in illumination intensity. Several diarylethene derivatives will be synthesized aiming to study different substituents’ effects on the fluorescence lifetime, quantum yields, and sensitivity to membrane potential changes.

Catherine Cobb, Darcey Wayment, Maegan Bousegard, Ashton Rogers, Raj Boopathy, Raj Nathaniel, Himanshu Raje

We undertook this study to develop a method that uses cellulose from the outer coating of capsules to conjugate lipase to iron nanoparticles. We created a mixture with 0.026g magnetized iron nanoparticles, 3 emptied and washed cellulose capsules, 5.0mL phosphate-buffered saline (PBS), and 0.083g bovine lipase. This mixture formed a film at room temperature within 48 hours. We created another film with the exact same composition without lipase enzyme. The film without lipase enzyme served as a negative control. Both films were individually dissolved with 20mL PBS in 50mL tubes. Iron nanoparticles from the dissolved films were separately collected with magnets at the bottom of the tube and further suspended in 10mL PBS. 0.005g cholesterol was treated with 50 microliters of iron nanoparticles in two separate microcentrifuge tubes with 450 microliters of PBS for fifteen minutes. Cholesterol was extracted in the organic phase from both control and treatment tube with 1mL of chloroform. The organic layers from both microcentrifuge tubes were passed through a 0.2 micron filter into separate chromatography vials. The presence of cholesterol was determined by GC-MS. We achieved 19.87% reduction of the height of cholesterol peak upon 10 minutes of lipase treatment. An absence of the cholesterol peak in the treatment sample indicated possible cholesterol degradation within fifteen minutes of lipase treatment. We intend to demonstrate the adhesion of lipase to iron nanoparticles.

Kabu Khadka, Sabina Dahal, Anthony Agu, Siva Murru

Colorectal cancer (CRC) is the third most commonly diagnosed and 2nd leading cause of cancer-related deaths worldwide, accounting for approximately 10% of all cancer cases. In 2023, there were an estimated 153,020 new cases of CRC in the USA. This disease is poorly chemo-sensitive toward the existing medical treatments so new and more effective therapeutic agents are urgently needed and intensely sought. We have recently developed pyrazole and pyrazolone based small molecule anticancer agents via Pd-catalyzed cross coupling reactions. Cross-coupling reactions have played a critical role enabling rapid expansion of structure–activity relationships (SAR) during drug discovery phase to identify a potent candidate and facilitate subsequent drug development processes. Despite these attractive synthetic properties, continuous development of these coupling reactions has been the focus of ongoing efforts to improve the selectivity, efficiency, and sustainability. Our focus has been on synthesizing diverse molecular hybrids of pyrazolones employing nucleophilic aromatic substitution (SNAr) for incorporation of aromatic rings and Pd-catalyzed Heck cross-coupling reactions for coupling of halo-aryl pyrazolones with sp2-hybridized vinyl substrates. Details of optimized reaction conditions, purification, characterization of the synthesized molecular hybrids will be presented. We will also discuss the antiproliferative activity of the synthesized compounds against colorectal cancer cells.

Krishna Prasad Sharma, Sean Roubion, Ganesh Dhakal, Guang-lin Zhao

Microwave absorption materials are critical in electromagnetic shielding, communication systems, and radar applications. This study investigates the microwave absorption characteristics of a composite material comprising Yttrium Barium Copper Oxide (YBCO) and Bismuth Oxide (Bi₂O₃). YBCO, a cuprate for a high-temperature superconductor, is combined with Bi₂O₃, a ceramic, exhibiting dielectric and magnetic properties, to enhance microwave absorption efficiency.   The composite material influences the synergistic effect between YBCO's conducting properties and Bi₂O₃'s dielectric properties, potentially resulting in enhanced microwave shielding capabilities. By varying the YBCO to Bi₂O₃ ratio, the study aims to optimize the composite's microwave absorption efficiency. Initial findings indicate that the YBCO-Bi₂O₃ composite may  be a promising material for high-frequency electronics and electromagnetic wave protection applications.

Haeyeon Yang, Khaliq Brown, Tanatswa Mujumi, Kondwani Phiri

Quantum dots are nanocrystal semi-conductor particles just a few nanometers in size that have both unique optical and electrical properties. Hence, they have the potential to enhance the efficiency of photovoltaic (solar) cells when used as wavelength conversion materials. Photovoltaic cells make up what is known as solar panels. A photovoltaic cell is essentially a p-n junction that absorbs light, releases electrons and holes that therefore create output voltage. The current absorption spectrum of silicon-based PV cells ranges from 400nm-1100nm, not utilizing infrared or ultraviolet region of solar spectrum. Implementing a Quantum Dot wavelength conversion film could increase lower wavelength intensities to those that could be absorbed by the solar cell. Increasing the wavelength spectra that current is generated through creation of a quantum dot film would increase the efficiency of the overall cell. In this talk, we present simulation results that enhance the efficiency of solar cells by a few percent by converting blue colored region of solar spectrum into red colored region.