In this study, a novel flexible ethanol gas sensor was created by the deposition of CoFe2O4 (CFO) thin film was on a thin mica substrate using pulsed laser deposition. Transition electron microscopy (TEM) investigations clearly demonstrated the successful growth of CFO on the mica, where a well-defined interface was observed. Ethanol gas-sensing studies showed optimal performance at 200 °C, with the highest response, 19.2, to 100 ppm ethanol. Operating the sensor in self-heating mode under 7 V applied voltage, which was corresponds to a temperature of approximately 200 °C, produced a maximal response to ethanol of 19.2. This aligned with the highest responses observed during testing at 200 °C, confirming the sensor’s accuracy and sensitivity to ethanol under self-heating conditions. In addition, the sensor exhibited good selectivity to ethanol and excellent flexibility; maintaining its high performance after bending and tilting up to 5000 times. As this is the first report on flexible self-heated CFO gas sensors, we believe that this research holds great promise for the future development of high-quality sensors based on this approach.

Present study focuses on the synthesis and characterisation of a lightweight ceramic material with electromagnetic interference (EMI) shielding properties, achieved using mullite containing micrometer-sized hollow spheres (cenospheres) and CoFe2O4 nanoparticles. The research explores compositions with varying CoFe2O4 content, ranging from 0 up to 20 wt.%. Сonventional sintering in an air atmosphere is carried out at a temperature between 1100-1300 °C. The addition of ferrite nanoparticles was found to enhance the sintering process of cenospheres, resulting in improved material density and mechanical properties. Furthermore, the study reveals a direct correlation between the concentration of ferrite nanoparticles and the electromagnetic properties of the. By increasing the concentration of ferrite nanoparticles, the electromagnetic shielding effect of the material (saturation magnetization (Ms) and remanent magnetization (Mr)) was observed to strengthen. These findings provide valuable insights into the design and development of lightweight ceramic materials with enhanced electromagnetic shielding capabilities. The synthesized ceramic material holds promise for various applications that require effective electromagnetic shielding, such as in electronics, telecommunications, and aerospace industries.

Urinary tract infections (UTIs) caused by pathogens, particularly E. coli, have spontaneously become resistant to antimicrobial drugs in recent years. Therefore, regular monitoring and alternative strategies for the antimicrobial agent are crucial for combating antimicrobial resistance and bacterial biofilms. Here, we report a new cobalt iron oxide-conjugated tin oxide nanocomposite that can kill bacteria and treat multidrug-resistant E. coli posing UTIs. Following the isolation and identification of E. coli, we tested 57/134 samples against sixteen commonly used antibiotics phenotypically using the disk diffusion method to determine their sensitivity pattern. Of the 57 E. coli isolates, 66% (38/57) were multidrug-resistant. The E. coli isolates were resistant to cephradine (70.17%), ceftriaxone (59.64%), and azithromycin (59.64%), followed by cefixime (54.38%), cefuroxime sodium (52.63%), and co-trimoxazole (50.87%). X-ray diffraction results showed the crystallite sizes were about 5.68 and 8.84 nm in pure SnO2 nanoparticles and 95% SnO2-5% CoFe2O4 nanocomposite, respectively. Energy-dispersive X-ray spectroscopy and Fourier transform infrared determined the fundamental structure of the nanocomposite, encompassing Co, Fe, Sn, and O. Moreover, FTIR measurements implied that the distinct functional groups in both SnO2 and CoFe2O4 nanoparticles existed in a 95% SnO2-5% CoFe2O4 nanocomposite. Field emission scanning electron microscope analysis uncovered that the SnO2-CoFe2O4 nanocomposite had a size of roughly 24 nm and was spherical. In addition, the biosynthesized SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite were evaluated for their antibacterial activity. At a minimum 100 µg/mL concentration, SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite showed high antibacterial activity. The SnO2 nanoparticles and SnO2-CoFe2O4 nanocomposite demonstrated antibacterial activity on multidrug-resistant E. coli at 10 ± 0.7 and 16 ± 0.8 mm zone of inhibition, respectively. In conclusion, the new SnO2-CoFe2O4 nanocomposite might be a potential candidate for treating UTIs caused by drug-resistant E. coli in the foreseeable future.

During the past few decades, hybrid nanoparticles (HNPs) based on a magnetic material and gold have attracted interest for applications in catalysis, diagnostics and nanomedicine. In this paper, magnetic CoFe2O4/Au HNPs with an average particle size of 10–20 nm decorated with 2-nm gold clusters were prepared using methionine as a reducer and an anchor between CoFe2O4 and gold. The obtained nanoparticles were studied by X-Ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy and X-Ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy techniques. The TEM images of the HNPs obtained after one, six and ten gold deposition cycles showed that the surface of cobalt ferrite was covered with gold nanoclusters, which slightly increased with an increase in the number of gold deposition cycles (from 2.12 ± 0.15 nm after one cycle to 2.46 ± 0.13 nm after ten cycles) without any change in surface density. The magnetic measurements showed that the obtained HNPs possessed typical ferrimagnetic behaviour, which corresponds to that of CoFe2O4 nanoparticles. The toxicity evaluation of the synthesised HNPs on Chlorella vulgaris indicated that they can be applied to biomedical applications such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging and biosensing.