The present study aimed to develop the synthesis of zinc oxide nanoparticles (ZnO-NPs) using the green method, with Aloe barbadensis leaf extract as a stabilizing and capping agent. In vitro antitumor cytotoxic activity, as well as the surface-functionalization of ZnO-NPs and their drug loading capacity against doxorubicin (DOX) and gemcitabine (GEM) drugs, were also studied. Morphological and structural properties of the produced ZnO-NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersion X-ray diffraction (EDX), UV-Vis spectrophotometry, Fourier-transform infrared analysis (FTIR), and X-ray diffraction (XRD). The prepared ZnO-NPs had a hexagonal shape and average particle size of 20–40 nm, with an absorption peak at 325 nm. The weight and atomic percentages of zinc (50.58% and 28.13%) and oxygen (26.71% and 60.71%) were also determined by EDAX (energy dispersive x-ray analysis) compositional analysis. The appearance of the FTIR peak at 3420 m^–1 confirmed the synthesis of ZnO-NPs. The drug loading efficiency (LE) and loading capacity (LC) of unstabilized and PEGylated ZnO-NPs were determined by doxorubicin (DOX) and gemcitabine (GEM) drugs. DOX had superior LE 65% (650 mg/g) and higher LC 32% (320 mg/g) than GEM LE 30.5% (30 mg/g) and LC 16.25% (162 mg/g) on ZnO-NPs. Similar observation was observed in the case of PEG-ZnO-NPs, where DOX had enhanced LE 68% (680 mg/g) and LC 35% (350) mg/g in contrast to GEM, which had LE and LC values of 35% (350 mg/g) and 19% (190 mg/g), respectively. Therefore, DOX was chosen to encapsulate nanoparticles, along with the untreated nanoparticles, to check their in vitro antiproliferative potential against the triple-negative breast cancer (TNBC) cell line (MDA-MB-231) through the MTT (3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide) assay. This drug delivery strategy implies that the PEGylated biogenically synthesized ZnO-NPs occupy an important position in chemotherapeutic drug loading efficiency and can improve the therapeutic techniques of triple breast cancer.

Nanomaterials have gained much attention in the field of environmental remediation, largely due to their high surface area-to-volume ratio and other unique physical, chemical, and biological characteristics that emerge due to its size effects. Metallic nanoparticles are traditionally manufactured using wet chemical processes; however, the chemicals utilized are generally hazardous and combustible. The biosynthesis of nanoparticles using a variety of plant resources is considered a green technology because it does not use toxic chemicals. This work focuses on the green synthesis of biogenetic silver nanoparticles and their use in the sequestration of colorants from aqueous solution. The extract of aquatic macrophyte Salvinia molesta (water hyacinth) has been employed to prepare silver nanoparticles by chemical reduction reaction. In the UV-visible spectrum of the synthesized silver nanoparticles, the absorbance peak was detected in the 420–430 nm range. The synthesized silver nanoparticles were used to sequester methylene blue (MB) dye in aqueous solution. About 121.04 mg/g was found as the highest adsorption capacity of methylene blue dye on the silver nanoparticles according to the Langmuir isotherm. It was observed that the experimental results and the pseudo-second order kinetics are in good agreement. As a result, the biosynthesized silver nanoparticle might be a potential adsorbent material in the field of environmental rehabilitation and cleanup.

Nanotechnology is generating interest of researchers toward cost-free and environment-friendly biosynthesis of nanoparticles. In this research, biosynthesis of stable copper nanoparticles has been done by using aloe vera leaves extract which has been prepared in de-ionized water. The aim of this study is the tracing of an object by green synthesis of copper oxide nanoparticles with the interaction of leaves extract and copper salt and its dye removal efficiency. The results have confirmed the efficient removal of Congo red (CR) dye using copper oxide nanoparticles. Furthermore, we have examined the effect of variables like concentration, time, pH, and adsorbent dosage. We have observed maximum 1.1 mg/g dye removal at 10 min time interval, pH 2, and 5 mg/g nanoparticles. The shape of the copper nanoparticles was spherical, and their range of grain was 80–120 nm. The EDX of synthesized nanoparticles showed copper 38% and 65% oxygen. UV spectrophotometer analysis confirms peak of the copper nanoparticles between 200–600 nm.

A green synthesis of copper oxide nanoparticles and its removal efficiency of azodye were studied. Biosynthesis of stable copper oxide nanoparticles were preformed using Aloe barbadensis leaf extract as a size and shape-directing agent for preparing of spherical copper oxide nanoparticles by calcination at 400 °C. The leaf extract of Aloe barbadensis was prepared in deionized water. The produced copper particles were calcined at 400 °C to produce copper oxide nanoparticles. The characterization of copper oxide nanoparticles was performed by XRD, SEM, FTIR, UV spectroscopy. The XRD analysis showed that the average particle size was between 5-30 nm. The shape of the copper oxide nanoparticles was spherical and cubic. EDX of the synthesized nanoparticles showed the composition consists of 68 % copper. The UV-visible spectrum analysis confirms an absorption peak at 200-400 nm of the produced CuO nanoparticles. The FTIR analysis of the copper oxide particles indicate the presence of the organometallic Cu-O bond between Cu and O. The obtained copper oxide was used as a removing agent of Congo red dye. The effect of variables like concentration, time, pH, adsorbent dosage were studied. It was observed from the results that the maximum dye removal occurs at pH of 4, the concentration of nanoparticles was 1 mg/L and the maximum time for dye removal was 120 min. The Langmuir isotherm model was calculated to study the adsorption efficiency of the Congo red dye on the produced copper oxide nanoparticles. The kinetics of pseudo second order is followed by adsorption. The calculated sum of square was 0.012 and r2 = 0.98. it was observed that the model fit the best and straight line with r2 value of 0.991 and probability value of 1.6E-5. The nanoparticles remove 70 % of the Congo red dye from its solution. This showed that the copper oxide nanoparticles has efficient capacity of azodye degradation.

The selected six specific bacterial and fungal strains, which caused oral teeth decay were analyzed by antimicrobial iron oxide (Fe₂O₃), copper oxide (Cu₄O₃), and zinc oxide (ZnO) nanoparticles synthesized by aloe barbadensis leaves extract, using agar well diffusion method with 0.9% saline solution. TMOs comparatively had not been focused on oral cavity infectious pathogens to analyze antimicrobial activity. In the present study, TMOs were characterized by UV, SEM, FTIR, and XRD. Oral infectious strains (Escherichia coli, Bacillus subtilis, Bacillus licheniformis, Klebsiella pneumonia) and fungal strains (Aspergillus niger, Candida albicans) were used as test microorganisms. The effect of different concentrations of TMO-NPs (2.5 µg/mL, 5 µg/mL, 10 µg/mL) was studied by zone of inhibition (ZOI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The zinc oxide nanoparticle with least particle-sized (37.8 nm) exhibited highest antimicrobial activity. In future, these zinc-oxide nanoparticles may be used in medicine for oral infectious diseases treatment.