The formation of bacterial biofilm is a major challenge in clinical applications. The main aim of this study is to describe the synthesis, characterization and biocidal potential of zinc oxide nanoparticles (NPs) against bacterial strain Pseudomonas aeruginosa. These nanoparticles were synthesized via soft chemical solution process in a very short time and their structural properties have been investigated in detail by using X-ray diffraction and transmission electron microscopy measurements. In this work, the potential of synthesized ZnO-NPs (∼10–15 nm) has been assessed in-vitro inhibition of bacteria and the formation of their biofilms was observed using the tissue culture plate assays. The crystal violet staining on biofilm formation and its optical density revealed the effect on biofilm inhibition. The NPs at a concentration of 100 µg/mL significantly inhibited the growth of bacteria and biofilm formation. The biofilm inhibition by ZnO-NPs was also confirmed via bio-transmission electron microscopy (Bio-TEM). The Bio-TEM analysis of ZnO-NPs treated bacteria confirmed the deformation and damage of cells. The bacterial growth in presence of NPs concluded the bactericidal ability of NPs in a concentration dependent manner. It has been speculated that the antibacterial activity of NPs as a surface coating material, could be a feasible approach for controlling the pathogens. Additionally, the obtained bacterial solution data is also in agreement with the results from statistical analytical methods.

Hematite (α-Fe₂O₃) forms iron oxide nanoparticles (NPs) which are thermally stable and have various electrochemical and optochemical applications.

Extensive researches have been done on the applications of zinc oxide nanoparticles (ZnO-NPs) for the biological purposes. However, the role and toxicity mechanisms of ZnO nanostructures (ZnO-NSts) such as nanoplates (NPls), nanorods (NRs), nanosheets (NSs), nanoflowers (NFs) on cancer cells are not largely known. Present study was focused to investigate the possible mechanisms of apoptosis induced by self-designed ZnO-NSts, prepared at fix pH via solution process and exposed against human T98G gliomas including various cancers and non-malignant embryonic kidney HEK293, MRC5 fibroblast cells. NSts were used for the induction of cell death in malignant human T98G gliomas including various cancers and compared with the non-malignant cells. Notably, NRs were found to induce higher cytotoxicity, inhibitory effects on cancer and normal cells in a dose dependent manner. We also showed that NRs induced cancer cell death through oxidative stress and caspase-dependent pathways. Furthermore, quantitative and qualitative analysis of ZnO-NSts have also been confirmed by statistical analytical parameters such as precision, accuracy, linearity, limits of detection and limit of quantitation. These self-styled NSts could provide new perception in the research of targeted cancer nanotechnology and have potentiality to improve new therapeutic outcomes with poor diagnosis.

Recently, nanoscale (<100 nm) inorganic materials, especially spherical shaped zinc oxide quantum dots (ZnO-QDs), have received a lot of attention from the broad community because of their potential utilization in various technologies. Due to their large surface to volume (S/V) ratios and extremely high reactivities, they can easily penetrate in various biological identities, such as cells and proteins, and therefore can sense, diagnose and cure different biological systems. The present study describes the facile synthesis of crystalline ZnO-QDs via a solution process. In addition, C2C12 myoblast cancer cells have been treated with different doses of ZnO-QDs at different incubation times (24, 48, 72 and 96 h). The rate of inhibition of cells was observed using an MTT assay, whereas the morphology of the cells was observed by confocal microscopy (CLSM). The MTT and CLSM investigations confirmed that with an increase in the incubation time, the population density of cancer cells was decreased when treated with ZnO-QDs. The dose dependent apoptosis correlated with intracellular production of reactive oxygen species (ROS) from C2C12 cancer cells was also measured in presence of ZnO-QDs. Moreover, the effect/apoptosis of these QDs was also checked in the presence of candidate genes such as caspase 3/7 with GAPDH. Reverse transcription polymerase chain reaction (RT-PCR) analysis demonstrates the up-regulation of caspase 3/7 genes in cells subsequently treated with ZnO-QDs at low and high concentrations.

The present paper describes a systematic study of bacterial growth measured and analysed via UV-visible spectroscopy, which reveals a strong dependence on pH. The morphology of the zinc oxide (ZnO) nanostructures (from sheets to flowers) varies with respect to change in pH and hence their different abilities to inhibit the bacterial (E. coli, S. aureus and K. pneumoniae) densities. The solution of zinc acetate dihydrate (Zn(CH₃COO)₂·2H₂O) was optimized by the addition of NaOH and HCl to obtain various pH values, ranging from pH 7 to 12. The optimized (pH 7, 10 and 12) solutions of zinc acetate dihydrate were further refluxed to obtain the different morphologies, and subsequently qualitative and quantitative determinations were studied. Absorption spectra of the resulting solutions were recorded at desired pH values, and all measurements were obtained at 600 nm with respect to corresponding control solution or blank. The linearity of the proposed method was evaluated at five concentration levels in the range from 0.5 to 2.0 μg mL⁻¹. Minute quantities of the different morphological nanostructures were used to determine the analytical parameters, such as correlation coefficient (r² = 0.9995, 0.9998, 0.9990), limit of detection (LOD, 0.053, 0.027 and 0.072 μg mL⁻¹), limit of quantitation (LOQ, 0.016, 0.083 and 0.220 μg mL⁻¹), respectively. Relative standard deviation and quantitative recoveries (RSD%) range from 0.113 to 1.58% and 98.66–100.88%. The morphologies of bacteria (E. coli, S. aureus and K. pneumoniae) and their interactions with synthesized ZnO nanostructures were analysed with Bio-TEM. The study suggests that the grown ZnO nanostructures with variable morphologies exhibit good accuracy and precision, revealed by statistical parameters and recovery data.