Microorganisms, dirt, and other air pollutants are major problems in textiles, which can generate an unpleasant odor during their growth. Herein, we have developed some novel antibacterial benzimidazolium-based dipodal ionic liquids that act as iron chelators, and they were loaded onto the wound-dressing gauze to enhance their antimicrobial properties for biomedical applications. The metal binding affinity of the synthesized ionic liquids was evaluated by UV–visible absorption and fluorescence spectroscopy, which reveals its selectivity toward Fe (III) ion. It is well-established that almost all bacteria require Fe (III) for survival and growth. To compete successfully for this essential nutrient, bacteria developed very efficient Fe (III) uptake mechanisms based on high-affinity Fe (III) chelators, so-called siderophores. Thus, keeping this in mind, all the prepared ionic-liquid-based iron chelators have been evaluated for their in vitro antibacterial activity against various pathogenic bacterial strains by colony forming unit (CFU) assay, and the MICs were determined by a broth microdilution method. The mechanism of action has also been explored by atomic force microscopy (AFM) and scanning electron microscopy (SEM), which reveals the bacterial cell wall deformity and cell wall rupturing that may lead to bacteria cell death. The most potent antibacterial compound, IL-3, was also investigated for its cytotoxicity against mammalian HeLa cell line and found to be nontoxic (IC50 > 100 μM). Further, the IL-3-coated wound-dressing gauze has been developed, fully characterized, and investigated against some Gram-positive and Gram-negative bacteria. Moreover, the IL-3-coated gauze was also evaluated for its hemostatic potential, and results reveal that the developed gauze shortens the time period required for blood clotting in comparison to simple dressing gauze and pledget that are commonly used in clinics. Thus, the potential antibacterial and hemostatic results exhibited by developed IL-3-coated gauze make it a useful tool that can be used in wards, ICU, and particularly, by military persons in war front areas.

In recent years, the biomimetic superhydrophobic coatings have received tremendous attention, owing to their potential in fabricating self-cleaning surfaces, in environmental applications. Consequently, extensive research has been devoted to create a superhydrophobic surface using the oxidized derivatives of CNTs and graphene. Thus, the design and development of a self-cleaning/superhydrophobic surface with good biocompatibility are an effective approach to deal with the bacterial infections related to biomedical devices used in hospitals. In this context, herein, we have developed the material based on ionic liquid (IL)-functionalized multiwalled carbon nanotubes (MWCNTs) for hydrophobic coatings, which was fully characterized with various techniques such as Fourier transform infrared, powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. We have evaluated the synthesized ILs for their antibacterial potential against the pathogenic bacterial strains such as Gram-positive (Staphylococcus aureus and methicillin-resistant S. aureus) and Gram-negative (Escherichia coli) bacterial strains. Further, atomic force and scanning electron microscopic studies have been performed to investigate the morphological changes to unravel the mechanism of action, whereas DNA binding study indicates the binding of IL-1d@MWCNT with DNA (K a = 2.390 × 104 M–1). Furthermore, the developed material (IL-1d@MWCNT) is coated onto the surface of polyvinyl chloride (PVC) and evaluated for hydrophobicity through water contact angle measurements and possesses long-term antibacterial efficiency against both under-investigating pathogenic strains. For the biocompatibility assay, the obtained coated PVC material has also been evaluated for its cytotoxicity, and results reveal no toxicity against viable cells. These all results are taken together, indicating that by coating with the developed material IL-1d@MWCNT, a robust self-sterilizing surface has achieved, which helps in maintaining a bacteria-free surface.

The spontaneous electron transfer between GaAs and ionic gold through the galvanic displacement reaction results in the formation of gold nanoparticles and a Au9Ga4 alloy. We investigated this process for decorating Legionella pneumophila and Escherichia coli, aiming at enhanced imaging of these bacteria. The surface of bacteria was modified with gold ions through the electrostatic linkage of ionic liquids with phosphate units of the bacterial cell wall. The modified bacteria were further incubated with an antibody-functionalized GaAs substrate. Due to a large gap in the reduction potential of gold and gallium ions, the induced reaction involving bacteria resulted in a reduction of the gold ions to gold nanoparticles and oxidation of GaAs to Ga2O3 and a Au9Ga4 alloy. The bacteria covered with a Au/AuGa nanoshell, if excited at 377 nm, show a bright emission at 447 nm originating from Au/Au9Ga4. This approach offers a simple and potentially less expensive method for high-contrast imaging of bacteria in comparison to the conventional methods of staining with different dyes or by conjugating green fluorescent proteins.

Zinc oxide (ZnO)-derived materials exhibit unique antibacterial, antifungal, and photochemical activities and are widely used in antibacterial formulations. In this work, ZnO nanosheets were prepared by green and cost-effective synthesis via a hydrothermal method, and the prepared ZnO nanosheets were further functionalized with an eco-friendly ionic liquid (IL). Thus, a sustainable approach was established to synthesize ZnO nanosheets. The functionalization of ZnO with the synthesized IL was fully characterized by advanced spectroscopic and microscopic techniques. The prepared ionic liquid-functionalized ZnO (IL@ZnO) showed self-organized layered-sheet arrangements caused by the intercalation of the IL onto the surface of ZnO nanosheets as revealed by scanning electron microscopy (SEM). The design of the IL comprised a carboxylic acid moiety for functionalization onto the surface of ZnO, whereas the hydrophobicity was tuned through the incorporation of a long alkyl chain. The developed IL@ZnO material was also tested against both Gram-positive and Gram-negative pathogenic bacteria for potential antibacterial activity by colony-forming unit (CFU) and minimum inhibitory concentration tests. The results revealed that the IL@ZnO exhibits significant antibacterial activity against tested strains. In particular, potent activity was observed against the Gram-positive skin-specific Staphylococcus aureus bacteria strain. The mechanism of bactericidal activity against bacteria was also explored along with the cytotoxicity toward mammalian cells, which reveals that the IL@ZnO is nontoxic in nature. To utilize the developed material owing to its bactericidal activity for practical applications, the IL@ZnO was fabricated onto the surface of cotton fabric, and its surface morphology was examined by SEM; the activity of IL@ZnO-treated cotton fabric was evaluated by the zone of inhibition assay. Additionally, the IL@ZnO-treated cotton fabric exhibited remarkable stability along with significant hydrophobicity and breathability and thus can be utilized as a biomaterial for biomedical applications, especially in medical masks, for reducing the risk of transmission of infectious diseases.

Despite the significant therapeutic use of cysteamine as drug in cystinosis, it also has some serious health issues such as idiopathic intracranial hypertension (IIH), Ehlers–Danlos syndrome, and eye related problems including blurred or loss of vision and pain due to eye movement, etc. Thus, it is important to measure accurate cysteamine levels in the body for clinical studies. However, most of the conventional methods used to detect cysteamine are time-consuming and expensive in nature. Therefore, in this regard, we have developed a chromogenic sensor which sequentially determines the Cu2+ metal ion and, consequently, exhibits potential ratiometric and selective colorimetric quantification of cysteamine in an aqueous/biological system. The morphology of the sensor was characterized by TEM, and it revealed some interesting features in that receptor 1 nanoparticles undergo self-assembly with the addition of Cu2+ metal ions which results in the filament formation (comet type) in aqueous medium and on subsequent addition of cysteamine to resultant complex 1·Cu2+; these comet type nanoparticle filaments undergo further aggregation process and develop into three-dimensional tree-like structure. Further, on the basis of obtained colorimetric results, we developed silica-based solid state sensor strips impregnated with complex 1·Cu2+, which displays colorimetric changes in accordance with present concentrations of cysteamine in blood serum and urine samples, wherein the intensity of yellow color decreased gradually after the addition of cysteamine, as revealed by HSV parameter through lab-on-mobile based diagnostics. The low detection limit (with naked eye) exhibited by developed solid state sensors leads to affordable and economic platforms for easy-to-use, reliable, and rapid colorimetric sensing of cysteamine in aqueous as well as biological test systems.