We may have heard about the concerns surrounding antibiotics. About how too much of it is being used and how, when used too much, it can cause bacteria to become resistant to antibiotics, a phenomenon called Antimicrobial resistance (AMR). India has even launched a “National Programme on AMR Containment” coordinated by the National Center for Disease Control (NCDC). In fact, there are so many antibiotics that are being used that they show up in our water bodies contaminating our drinking water supplies. The presence of these antibiotics is not easy to detect either.
In a bid to aid in the detection of such antibodies, researchers from Jawaharlal Nehru University, New Delhi, and the National Institute of Immunology, New Delhi, have developed a novel quantum dot that could help detect such molecules. The study showed that the optical properties of Quantum dots made of zinc oxide (ZnO) can be tweaked or "tuned" by adding polymers. In this study, the scientists used two types of polymers: polyvinyl alcohol (PVA) and polyvinylpyrrolidine (PVP). Each polymer changes how the quantum dots behave, especially how they fluoresce - the property of a material where it absorbs radiation to emit visible light or glow.
Researchers found that by capping ZnO Quantum Dots (QDs) with PVA and PVP polymers, they could alter the quantum dots' optical properties, specifically their light absorption and bandgap. The "bandgap" refers to the energy difference between the valence band (where electrons are) and the conduction band (where electrons can move freely to conduct electricity). Altering these properties impacts how the quantum dots interact with light, which is crucial for their role in detecting antibiotics through fluorescence.
Once capped, the QD undergoes a process called polymer functionalization, during which the quantum dots acquire a positive charge. This increase in surface charge enhances the QDs' interaction capabilities with specific antibiotics. When one of these polymer-functionalized ZnO quantum dots meets a specific antibiotic molecule, they attach to the molecule and the glow or fluorescence changes. This change helps scientists know exactly what antibiotics are and how many are present. When certain antibiotics are around, the glow dims, and scientists can detect even tiny amounts of antibiotics down to nanomolar concentrations.
The study demonstrated that functionalized ZnO QDs had specific interactions with certain antibiotics. Specifically, PVA-ZnO QDs were highly responsive to Ciprofloxacin, whereas PVP-ZnO QDs were more responsive to Moxifloxacin. This specificity is an advantage over non-functionalized ZnO QDs, which did not show such a targeted response to antibiotics.
The research team successfully tested it in tap water, and the results showed promising results that suggest these sensors could be effectively used in real-world conditions. The polymers, PVA and PVP, also allow the quantum dots to be specifically selective for different antibiotics, meaning they can target and reveal different types of antibiotic molecules.
The research not only helps monitor water quality but also has potential applications in healthcare and pharmaceuticals. If this technology can be refined, it might lead to quicker, cost-effective methods to test for antibiotics in medical settings, ensuring medications are only used when necessary and appropriate. It could also mean health and environmental agencies can detect and monitor antibiotic contamination sooner and more accurately, leading to more responsive measures to control it. But more importantly, the discovery of tuning the optical properties of the QD with a polymer could lead to a whole array of sensors we haven’t even thought of.
This research news was partly generated using artificial intelligence and edited by an editor at Research Matters