Maha A. Khalil’s research while affiliated with Taif University and other places

Background and Aim The rapid advancement of nanotechnology has opened new avenues for biomedical applications, particularly in antimicrobial, anti-inflammatory, and anticancer therapies. Green synthesis of zinc oxide nanoparticles (ZnO-NPs) using plant extracts offers an eco-friendly and biocompatible alternative to traditional chemical methods. This study explores the synthesis of ZnO-NPs using Syzygium aromaticum (clove) bud extract (CBE) and evaluates their multifaceted biomedical potential, including anticancer, antibacterial, and anti-inflammatory properties. Methods Clove bud extract-zinc oxide nanoparticles (CBE-ZnO-NPs) were synthesized and characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and Brunauer-Emmett-Teller (BET) analyses to confirm their size, morphology, elemental composition, and surface properties. The anticancer efficacy was tested against tongue carcinoma (HNO-97) cells using the sulforhodamine B (SRB) assay. Antibacterial activity was assessed against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus, while anti-inflammatory potential was evaluated using a mouse macrophage cell line (RAW 264.7). Results The SEM analysis confirmed a non-uniform shape of ZnO-NPs, while FTIR revealed functional groups responsible for stabilization and bioactivity. DLS measurements indicated an average particle size of 249.8 nm with a zeta potential of −3.38 mV, ensuring moderate colloidal stability. BET analysis demonstrated a high porosity (30.039 m²/g) and a mean particle size of 19.52 nm. CBE-ZnO-NPs exhibited moderate anticancer activity against tongue carcinoma cells (IC50 > 100 µg/mL), potent antibacterial activity (MIC = 62.5–125 μg/mL), and anti-inflammatory effects (IC50 = 69.3 µg/mL). Conclusion This study highlights the potential of CBE-ZnO-NPs as a promising multi-functional nanomaterial with potent antibacterial, anticancer, and anti-inflammatory properties. The findings pave the way for further exploration of ZnO-based nanotherapeutics in biomedical applications, particularly in cancer therapy, infection control, and inflammatory disorders.

Oral bacterial pathogens, including Bacillus species, form biofilms that enhance antibiotic resistance, promote bacterial adherence, and maintain structural integrity. The ability of bacteria to form biofilms is directly linked to several oral diseases, including gingivitis, dental caries, periodontitis, periapical periodontitis, and peri-implantitis. These biofilms act as a predisposing factor for such infections. Nanoparticles, known for their strong antibacterial properties, can target specific biofilm-forming microorganisms without disturbing the normal microflora of the oral cavity. This study focuses on the biofilm-forming ability and clindamycin (CM) resistance of Bacillus species found in the oral cavity. It aims to evaluate the antibacterial and antibiofilm properties of zinc oxide nanoparticles (ZnO-NPs) against oral Bacillus species and assess the effectiveness of combining CM with ZnO-NPs in reducing antibiotic resistance. The antibacterial susceptibility of Bacillus isolates was tested using ZnO-NPs and CM, demonstrating synergistic effects that reduced the minimum inhibitory concentrations by up to 8-fold. The fractional inhibitory concentration (FIC) index indicated a significant synergistic effect in most strains, with FIC values ranging from 0.375 to 0.5. It was found that the majority of Bacillus strains exhibited significant biofilm-forming capabilities, which were reduced when treated with the ZnO-NPs and CM combination. The study also evaluated the cytotoxicity of ZnO-NPs on cancer cells (CAL27) and normal fibroblasts (HFB4). CAL27 cells showed stronger cytotoxicity, with an IC50 of 52.15 µg/mL, compared to HFB4 cells, which had an IC50 of 36.3 µg/mL. Genetic analysis revealed the presence of biofilm-associated genes such as sipW and tasA, along with antibiotic resistance genes (ermC), which correlated with the observed biofilm phenotypes. Overall, this study demonstrates the potential of combining ZnO-NPs with CM to overcome antibiotic resistance and biofilm formation in the oral bacterial pathogens, Bacillus species. These findings suggest new approaches for developing more effective dental treatments targeting oral biofilm-associated infections and antibiotic resistance.

The pervasiveness of microplastics (MPs) in terrestrial and aquatic ecosystems has become a significant environmental concern in recent years. Because of their slow rate of disposal, MPs are ubiquitous in the environment. As a consequence of indiscriminate use, landfill deposits, and inadequate recycling methods, MP production and environmental accumulation are expanding at an alarming rate, resulting in a range of economic, social, and environmental repercussions. Aquatic organisms, including fish and various crustaceans, consume MPs, which are ultimately consumed by humans at the tertiary level of the food chain. Blocking the digestive tracts, disrupting digestive behavior, and ultimately reducing the reproductive growth of entire living organisms are all consequences of this phenomenon. In order to assess the potential environmental impacts and the resources required for the life of a plastic product, the importance of life cycle assessment (LCA) and circularity is underscored. MPs-related ecosystem degradation has not yet been adequately incorporated into LCA, a tool for evaluating the environmental performance of product and technology life cycles. It is a technique that is designed to quantify the environmental effects of a product from its inception to its demise, and it is frequently employed in the context of plastics. The control of MPs is necessary due to the growing concern that MPs pose as a newly emergent potential threat. This is due to the consequences of their use. This paper provides a critical analysis of the formation, distribution, and methods used for detecting MPs. The effects of MPs on ecosystems and human health are also discussed, which posed a great challenge to conduct an LCA related to MPs. The socio-economic impacts of MPs and their management are also discussed. This paper paves the way for understanding the ecotoxicological impacts of the emerging MP threat and their associated issues to LCA and limits the environmental impact of plastic.

Some essential information on gut bacterial profiles and their unique contributions to food digestion in wood-feeding termites (WFT) and soil-feeding termites (SFT) is still inadequate. The feeding type of termites is hypothesized to influence their gut bacterial composition and its functionality in degrading lignocellulose or other organic chemicals. This could potentially provide alternative approaches for the degradation of some recalcitrant environmental chemicals. Therefore, metagenomic analysis can be employed to examine the composition and functional profiles of gut bacterial symbionts in WFT and SFT. Based on the metagenomic analysis of the 16S rRNA gene sequences of gut bacterial symbionts in the WFT, Microcerotermes sp., and the SFT, Pericapritermes nitobei, the findings revealed a total of 26 major bacterial phyla, with 18 phyla commonly represented in both termites, albeit in varying abundances. Spirochaetes dominated the bacterial symbionts in Microcerotermes sp. at 55%, followed by Fibrobacters, while Firmicutes dominated the gut bacteria symbionts in P. nitobei at 95%, with Actinobacteria coming in second at 2%. Furthermore, the Shannon and phylogenetic tree diversity indices, as well as the observed operational taxonomic units and Chao 1 richness indices, were all found to be higher in the WFT than in the SFT deduced from the alpha diversity analysis. Based on the principal coordinate analysis, exhibited a significant distance dissimilarity between the gut bacterial symbionts. The results showed that the gut bacterial composition differed significantly between the WFT and SFT. Furthermore, Tax4Fun analysis evaluated bacterial functions, revealing the predominance of carbohydrate metabolism, followed by amino acid metabolism and energy metabolism in both Microcerotermes sp. and P. nitobei termites. The results implicated that bacterial symbionts inhabiting the guts of both termites were actively involved in the degradation of lignocellulose and other recalcitrant compounds.

Background and aim: The escalating prevalence of Methicillin-Resistant Staphylococcus aureus

Biopolymers such as chitosan and pectin are currently attracting significant attention because of their unique properties, which are valuable in the food industry and pharmaceutical applications. These properties include non-toxicity, compatibility with biological systems, natural decomposition ability, and structural adaptability. The objective of this study was to assess the performance of two different ratios of pectin–chitosan polyelectrolyte composite (PCPC) after applying them as a coating to commercially pure titanium (CpTi) substrates using electrospraying. The PCPC was studied in ratios of 1:2 and 1:3, while the control group consisted of CpTi substrates without any coating. The pull-off adhesion strength, cytotoxicity, and antibacterial susceptibility tests were utilized to evaluate the PCPC coatings. In order to determine whether the composite coating was the result of physical blending or chemical bonding, the topographic surface parameters were studied using Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). PCPC (1:3) had the highest average cell viability of 93.42, 89.88, and 86.85% after 24, 48, and 72 h, respectively, as determined by the cytotoxicity assay, when compared to the other groups. According to the Kirby–Bauer disk diffusion method for testing antibacterial susceptibility, PCPC (1:3) showed the highest average diameter of the zone of inhibition, measuring 14.88, 14.43, and 11.03 mm after 24, 48, and 72 h of incubation, respectively. This difference was highly significant compared to Group 3 at all three time periods. PCPC (1:3) exhibited a significantly higher mean pull-off adhesion strength (521.6 psi) compared to PCPC (1:2), which revealed 419.5 psi. PCPC (1:3) coated substrates exhibited better surface roughness parameters compared to other groups based on the findings of the AFM. The FTIR measurement indicated that both PCPC groups exhibited a purely physical blending in the composite coating. Based on the extent of these successful in vitro experiments, PCPC (1:3) demonstrates its potential as an effective coating layer. Therefore, the findings of this study pave the way for using newly developed PCPC after electrospraying coating on CpTi for dental implants.

The presence of high salinity levels in textile wastewater poses a significant obstacle to the process of decolor-izing azo dyes. The present study involved the construction of a yeast consortium HYC, which is halotolerant and was recently isolated from wood-feeding termites. The consortium HYC was mainly comprised of Sterigmatomyces halophilus SSA-1575 and Meyerozyma guilliermondii SSA-1547. The developed consortium demonstrated a decolourization efficiency of 96.1% when exposed to a concentration of 50 mg/l of Reactive Black 5 (RB5). The HYC consortium significantly decolorized RB5 up to concentrations of 400 mg/l and in the presence of NaCl up to 50 g/l. The effects of physicochemical factors and the degradation pathway were systematically investigated. The optimal pH, salinity, temperature, and initial dye concentration were 7.0, 3%, 35 • C and 50 mg/l, respectively. The co-carbon source was found to be essential, and the addition of glucose resulted in a 93% decolorization of 50 mg/l RB5. The enzymatic activity of various oxido-reductases was assessed, revealing that NADH-DCIP reductase and azo reductase exhibited greater activity in comparison to other enzymes. UV-Visible (UV-vis) spectrophotometry, Fourier-transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS) were utilized to identify the metabolites generated during the degradation of RB5. Subsequently, a metabolic pathway was proposed. The confirmation of degradation was established through alterations in the functional groups and modifications in molecular weight. The findings indicate that this halotolerant yeast consortium exhibits promising potential of degrading dye compounds. The results of this study offer significant theoretical basis and crucial perspectives for the implementation of halotolerant yeast consortia in the bioremediation of textile and hypersaline wastewater. This approach is particularly noteworthy as it does not produce aromatic amines.