Research Project: Stimuli Responsive Materials for the Rapid Detection and Treatment of Healthcare Associated Infections
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Contributors
Funders
ID
EC.00138
Authors
Nizamoğlu, Sedat
Faculty Member
Publications
Antibacterial type-II INP/ZNO quantum dots via multimodal reactive oxygen species
(Elsevier B.V., 2024)
Department of Electrical and Electronics Engineering
Department of Chemistry
Graduate School of Health Sciences
Graduate School of Sciences and Engineering
School of Medicine
The emergence of multidrug-resistant bacteria as a global health threat has necessitated the exploration of alternative treatments to combat bacterial infections. Among these, photocatalytic nanomaterials such as quantum dots (QDs) have shown great promise and type-I QDs have been investigated thus far. In this study, we introduce type-II InP/ZnO core/shell QDs that are ligand-exchanged with a short-chain inorganic sulfide ion (S2−) for antibacterial activity. Interestingly, InP/ZnO QDs simultaneously generate reactive oxygen species (ROS) including hydroxyl (•OH) and superoxide (O2•−) radicals, while only O2•− radicals can be released by the type-I sulfide-capped InP/ZnS QDs. The optimized nanostructure achieved effective inhibition of Pseudomonas aeruginosa and Escherichia coli bacteria growth to the level of 99.99% and 70.31% under low-intensity green light illumination of 5 mW.cm−2. Our findings highlight the importance of type-II QDs as a new avenue for developing effective antibacterial agents against drug-resistant pathogens. © 2023 Elsevier B.V.
Ultra-Effective Light-Activated Antibacterial Activity via Carboxyl Functionalized Graphene Quantum Dots and Films
(Wiley, 2025)
Kaleli, Humeyra Nur
Hassnain, Muhammad
Önal, Asım
van Hofwegen, Laure S.
Balraadjsing, Payal P. S.
Bacterial infections are a major healthcare concern. Clinical application of photo-activated quantum dots to efficiently treat bacterial infections has been hindered by inadequate production of reactive oxygen species. In this study, photoactive antimicrobial carboxyl-functionalized graphene quantum dots (cGQDs) are synthesized with an exceptionally high singlet oxygen (1O2) quantum yield of 0.88. Compared to non-functionalized GQDs, cGQDs exhibit over a 20-fold enhancement in the 1O2 quantum yield. According to the density functional theory simulations, the dramatic increase of 1O2 quantum yield is due to significantly enhanced spin-orbit coupling between singlet and triplet excited states of GQDs with addition of & horbar;COOH groups. Under low-intensity blue light (5 mW cm- 2), Staphylococcus aureus is completely eliminated with just 0.8 mu g mL-1 of cGQDs, and a minimum bactericidal concentration (MBC) of 0.4 mu g mL-1 is determined, representing the lowest MBC reported against S. aureus using light-activated quantum dots. Layer-by-layer assembly of cGQD films also results in over a 99.9% reduction against multi-drug resistant Staphylococcus aureus and Escherichia coli under illumination. cGQDs, both in suspension and as a nano-assembled film, exhibit good cell viability in mammalian cells under both dark and light conditions. These results highlight the strong potential of cGQDs as an effective nanomaterial for antibacterial applications.
Sulfide-capped InP/ZnS quantum dot nanoassemblies for a photoactive antibacterial surface
(American Chemical Society, 2024)
Vanalakar, Sharadrao
Alkan, Fahri
Department of Molecular Biology and Genetics
Department of Chemistry
Department of Chemical and Biological Engineering
Semiconductor photocatalysis has recently emerged as a promising method for microbial inactivation. So far, quantum dots have generally been investigated as antibacterial suspension. Instead, here we demonstrate a InP/ZnS quantum dot nanoassembly film against both Gram-negative and Gram-positive bacteria. For effective operation in the solid phase, a thin layer of ZnS shell was grown on InP QD and the native long-chain ligand of stearic acid was replaced with sulfide that led to a high quantum yield of superoxide generation as 4.9%. QDs are assembled onto solid surfaces through sequential dip coating of positively charged poly(diallyldimethylammonium chloride) and negatively charged QDs. These QD nanoassemblies demonstrate growth inhibition against Escherichia coli and multidrug-resistant Staphylococcus aureus under illumination. Interestingly, such an approach can be directly applied to irregular surfaces, as well. This study unveils the potential of the nanoengineering of QDs for antibacterial coatings.