Nanomaterials for biomedical and industrial hybrid sensors

Abstract

Various industries nowadays are interested to obtain new, effective, cost-efficient, highly sensitive and selective hybrid sensors for gas detection. Therefore, the change to hydrogen as a clean and versatile energy carrier in the industrial field require hydrogen detectors, while in the medical field hydrogen serves as a biomarker for lactose intolerance and potential therapeutical gas. Recent studies, offer proper solutions by obtaining composite sensors. A fairly new direction for such types of hybrid sensors are metal-oxides coated with different polymers, which work like sieves for various gas molecules. Such hybrid sensors for hydrogen and 2-propanol detection have been obtained by coating several samples of CuO/Cu2O/ZnO:Fe, TiO2 and CuO/TiO2 with P(V3D3) which increased their response values several folds. In this regard, relatively good responses towards gas and vapor have been registered. Furthermore, different thermal treatments, showed that hybrid sensors could be improved to get even higher response. Another method, studied recently by our groups is using zeolitic imidazolate frameworks (ZIF) atop different metal oxide structures such as Al2O3/CuO, which is also one of the studies presented in this paper. This research direction shows that it is possible to obtain higher sensitivity due to ZIF-7 for hydrogen and acetone, making it a possible two-in-one sensor operating just at different temperatures. In a similar way a two-in-one sensor for both hydrogen and ammonia detection due to composite materials used for its production has been presented: TiO2 and PV4D4, which included thermal treatment of TiO2 at 610°C followed by coverage with a 25 nm thick polymer film. Thus, ammonia registered a 52% higher response from baseline, while for hydrogen it was even 100%. In response to industry demands the most interesting and promising path is investigating various hybrid material combinations to obtain either ultra-selective hydrogen detectors through heterostructures of metal oxides or through different polymer coatings highly tunable gas detectors for manufacturing processes. The development of hybrid structures based on organic-inorganic and inorganic-inorganic unlocks significant potential for gas sensing optimization, enabling innovative applications in biomedical and industrial fields, including exhaled breath analysis and detection of gaseous biomarkers. In our research hybrid composite materials consisting of Polymer/CuO/Cu2O/ZnO:Fe and ZIF-7-coated Al2O3/CuO/Cu2O nanostructures were studied for their potential application in sensor technologies. By combining several nanomaterials, especially forming hybrid nanomaterials, sensor performance can be improved by counteracting interfering ambient. These hybrid-based sensors provide enhanced response to target vapor or gases, namely acting as sieve nanostructures to reduce humidity interference and improve selectivity.