Journal of Nanotechnology

This study synthesized silver nanoparticles (Ag-NPs) using silver nitrate (AgNO₃) as the ion source and sodium tripolyphosphate (STPP) as reducing as well as capping agents. The synthesized Ag-NPs were confirmed initially using Ag-NPs specific λ_max at 410 nm with UV-Vis spectrophotometry and homogenously distributed, 100–300 nm size, and round-shaped particles were realized through atomic force microscopy (AFM) and transmission electron microscopy (TEM) image analysis. The various reaction condition-based studies revealed 0.01 M AgNO₃ yields maximum particle after 4 h reduction with 1% STPP. Bacillus spp. (n = 23/90) and Pseudomonas spp. (n = 26/90) were isolated from three different poultry farms for evaluating the antibacterial activity of Ag-NPs. Among the PCR confirmed isolates, 52% (12/23) Bacillus spp. were resistant to ten antibiotics and 65% (17/26) Pseudomonas spp. were resistant to eleven antibiotics. The representative resistant isolates were subjected to antibacterial evaluation of synthesized Ag-NPs following the well diffusion method, revealing the maximum sensitive zone of inhibition 19 ± 0.2 mm against Bacillus spp. and 17 ± 0.38 mm against Pseudomonas spp. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of Ag-NPs were 2.1 μg/ml and 8.4 μg/ml, respectively, for broad-spectrum application. Finally, the biocompatibility was determined by observing the viability of Ag-NP-treated BHK-21 cell through trypan blue-based exclusion assay revealing nonsignificant decreased of cell viability ≤2MIC doses. Thus, the synthesized Ag-NPs were proven as biocompatible and sensitive to both Gram-positive and Gram-negative bacteria of the poultry farm environmental samples.

Hydroxyapatite nanoparticles (nHAPs) have been recognized for potent antitumor effects in certain cancer cells, making them good candidates as drug delivery agents and tumor therapeutics with fewer than normal side effects. This study is aimed to correlate cell proliferation inhibition with the size and morphology of nHAPs in a human breast cancer cell line as well as in normal tissue cells. We present our in vitro experimental evidence that nHAPs with sizes smaller than 50 nm have high inhibitory activity against human MCF-7 breast cancer cell lines. Based on our experimental data, normal fibroblast cells (NIH 3T3) were relatively more viable upon treatment with the nanoconstructs. The present study indicates that nHAPs can be engineered as nontoxic specific inhibitors as efficient breast cancer therapeutics in humans.

A Fe₃O₄@ZnO/C nanocomposite with a core-shell structure was synthesized using the co-precipitation method. To prevent the aggregation of the Fe₃O₄ magnetic particles, polyethylene glycol (PEG) was added. The X-ray diffractometer (XRD) results confirmed the formation of Fe₃O₄ and ZnO phases, with Fe₃O₄ having a cubic crystal system and ZnO having a hexagonal crystal system. Carbon in Fe₃O₄@ZnO/C had no effect on the crystal structure of Fe₃O₄@ZnO. Images from transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed that the nanocomposite formed a core-shell structure. The Fourier transform infrared (FTIR) spectra verified the presence of bonds among ZnO, Fe₃O₄, and carbon. The appearance of the stretching vibration of the C≡C bond on the Fe₃O₄@ZnO/C sample revealed the nanocomposites’ carbon coupling. Photoluminescence (PL) spectroscopy was used to characterize the optical properties of the nanocomposites. Based on the results of the PL, the sample absorption of visible light was in the wavelength range of 400–700 nm. The photoluminescence of Fe₃O₄@ZnO differed from that of the Fe₃O₄@ZnO/C, especially in the deep-level emission (DLE) band. There was a phenomenon of broadening and shift of the band at a shorter wavelength, namely, in the blue wavelength region. Magnetic properties were characterized by vibrating-sample magnetometry (VSM). Based on the VSM results, the sample coupled with carbon exhibited a decrease in magnetic saturation. The presence of carbon changed photon energy into thermal energy. So, this material, apart from being a bioimaging material, can also be developed as a photothermal therapy material.

This study provides the formation of semiconductor nanowires (NWs) with a singular facet and a curved end surface by the vapor-liquid-solid (VLS) process that is analyzed and explained in details. Given the evidence, it is confirmed that the wettability of a liquid catalyst droplet on a crystal surface and the contact angle between the droplet and crystal play an essential role in the VLS process of NWs development. It is shown that for the VLS mechanism, the formation of NWs depends on the reduction in activation barrier to crystallization caused by the release of surplus-free energy by a spheroidizing drop in the region of the triple junction during the process of lowering surface area. This decreases the necessary supersaturation for the development of NW vertex facets at a fixed growth rate. The source of the extra free energy that drives the catalyst droplet movement during the steady-state development of NWs is the droplet’s outer surface. During the formation of NWs, those angles of inclination of the lateral surface NWs and droplet contact are obtained at which the solid/vapor, solid/liquid, and liquid/vapor interfaces experience the smallest increase in free energy. The wetting hysteresis is demonstrated to occur at the vertex of NWs, and the contact angle of a catalyst droplet may be regarded as an independent and fully-fledged thermodynamic parameter of the system’s state.

The textile industry’s discharges have long been regarded as severe water pollution. The photocatalytic degradation of dyes using semiconductors is one of the crucial methods. The present study efficiently used the mechanical method to synthesize Iron oxide Nanoparticles. XRD, FT-IR, UV-Vis DRS, and Raman analyses were performed to analyze the structural and optical. From the data provided by XRD and Raman data, we believed that the as-synthesized Iron oxide was pure hematite (α-Fe₂O₃) with a hexagonal structure. Additionally, the EDS results show that the synthesized material is pure. By adjusting specific parameters, including the dye concentration, the catalyst dosage, the pH, and the oxidizing agent such as H₂O₂ and K₂S₂O₈, the degradation of eosin yellowish using Fe₂O₃ as a photocatalyst has been discussed. Additionally, the kinetics of eosin yellowish degradation has been studied. A study was also conducted using Fe₂O₃ nanoparticles attached to polyurethane polymer (PU) to investigate its photocatalytic activity on methylene blue, methyl orange, and indigo carmine. In 30 minutes, nearly 90% of the dyes had degraded. The total organic carbon (TOC) analysis confirmed this result.

Interfacial carrier transfer kinetics is critical to the efficiency and stability of perovskite solar cells. Herein, we measure the regeneration rate constant, absorption cross-section, reduction rate constant, and conductivity of hole transport layered perovskites using scanning electrochemical microscopy (SECM). The SECM feedback revealed that the regeneration rate constant, absorption cross-section, and reduction rate constant of the nickel oxide (NiO) layer perovskite layer are higher than those of the poly (3,4-ethyenedioxythiophene)-poly (styrenesulfonate) layered perovskite. Also, at a specific flux density (), the value of the regeneration rate constant (k_eff) in both blue and red illuminations for the NiO/CH₃NH₃PbI₃ film is significantly higher than in both PEDOT: PSS/CH₃NH₃PbI₃ and FTO/CH₃NH₃PbI₃ films. The difference in k_eff between layered and nonlayered perovskite conforms to the impact of the hole conducting layer on the charge transfer kinetics. According to the findings, SECM is a powerful approach for screening an appropriate hole transport layer for stable perovskite solar cells.