Biotemplate of albumen for synthesized iron oxide quantum dots nanoparticles (QDNPs) and investigation of antibacterial effect against pathogenic microbial strains

Influence of Physicochemical Properties of Iron Oxide Nanoparticles on Their Antibacterial Activity

The increasing occurrence of infectious diseases caused by antimicrobial resistance organisms urged the necessity to develop more potent, selective, and safe antimicrobial agents. The unique magnetic and tunable properties of iron oxide nanoparticles (IONPs) make them a promising candidate for different theragnostic applications, including antimicrobial agents. Though IONPs act as a nonspecific antimicrobial agent, their antimicrobial activities are directly or indirectly linked with their synthesis methods, synthesizing precursors, size, shapes, concentration, and surface modifications. Alteration of these parameters could accelerate or decelerate the production of reactive oxygen species (ROS). An increase in ROS role production disrupts bacterial cell walls, cell membranes, alters major biomolecules (e.g., lipids, proteins, nucleic acids), and affects metabolic processes (e.g., Krebs cycle, fatty acid synthesis, ATP synthesis, glycolysis, and mitophagy). In this review, we will investigate the antibacterial activity of bare and surface-modified IONPs and the influence of physiochemical parameters on their antibacterial activity. Additionally, we will report the potential mechanism of IONPs' action in driving this antimicrobial activity.

Iron oxide nanoparticles carried by probiotics for iron absorption: a systematic review

BACKGROUND

One-third of the world's population has anemia, contributing to higher morbidity and death and impaired neurological development. Conventional anemia treatment raises concerns about iron bioavailability and gastrointestinal (GI) adverse effects. This research aims to establish how iron oxide nanoparticles (IONPs) interact with probiotic cells and how they affect iron absorption, bioavailability, and microbiota variation.

METHODS

Pointing to the study of the literature and developing a review and critical synthesis, a robust search methodology was utilized by the authors. The literature search was performed in the PubMed, Scopus, and Web of Science databases. Information was collected between January 2017 and June 2022 using the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) protocols for systematic reviews and meta-analyses. We identified 122 compatible research articles.

RESULTS

The research profile of the selected scientific articles revealed the efficacy of IONPs treatment carried by probiotics versus conventional treatment. Therefore, the authors employed content assessment on four topics to synthesize previous studies. The key subjects of the reviewed reports are the characteristics of the IONPs synthesis method, the evaluation of cell absorption and cytotoxicity of IONPs, and the transport of IONPs with probiotics in treating anemia.

CONCLUSIONS

To ensure a sufficient iron level in the enterocyte, probiotics with the capacity to attach to the gut wall transport IONPs into the enterocyte, where the maghemite nanoparticles are released.

Enhanced fluorescent iron oxide quantum dots for rapid and interference free recognizing lysine in dairy products

In this work, a simple, easy and selective method for sensing lysine in an acidic medium was developed based on fluorescent iron oxide quantum dots (IO QDs). IO QDs using the hydrothermal method were prepared with different conditions (concentration of NPs, amount of citric acid, heating time, heating temperature, and total volume in the hydrothermal reactor) where iron oxide nanoparticles (IO NPs) were used as the starting materials. TEM, FTIR, UV-Vis Spectrometry, fluorescence spectrometry, Powder XRD, VSM were used to characterize the as-prepared IO QDs. The surface of the IO QDs contained -OH, -COO^-, and other functional groups that acted as a bridge to bind the IO QDs nanoprobe with the surrounding analytes. Under acidic conditions (pH 3.0), IO QDs exhibited a rapid and interference-free fluorescence enhancement behavior after adding lysine within 2 min at room temperature, whereas other amino acids had no effect on IO QDs fluorescence. Therefore, the IO QDs prepared in this study have shown potential in lysine sensing applications. The results showed that the relative FL intensity was linear with lysine concentration in the range of 1-100 μM and had a detection limit of 0.66 μM. This proposed method has high selectivity for lysine over other amino acids, and the developed methods were used in real sample with good recoveries. Under relatively acidic conditions, a specific and fast lysine interaction was observed, resulting in the successful of IO QDs as the fluorescent probe for rapid and interference-free lysine assessment in dairy products.

Elemental Analysis and In Vitro Evaluation of Antibacterial and Antifungal Activities of Usnea barbata (L.) Weber ex F.H. Wigg from Călimani Mountains, Romania

This study aims to complete our research on Usnea barbata (L.) Weber ex F.H. Wigg (U. barbata) from the Călimani Mountains, Romania, with an elemental analysis and to explore its antibacterial and antifungal potential. Thus, we analyzed twenty-three metals (Ca, Fe, Mg, Mn, Zn, Al, Ag, Ba, Co, Cr, Cu, Li, Ni, Tl, V, Mo, Pd, Pt, Sb, As, Pb, Cd, and Hg) in dried U. barbata lichen (dUB) by inductively coupled plasma mass spectrometry (ICP-MS). For the second study, we performed dried lichen extraction with five different solvents (ethyl acetate, acetone, ethanol, methanol, and water), obtaining five U. barbata dry extracts (UBDE). Then, using an adapted disc diffusion method (DDM), we examined their antimicrobial activity against seven bacterial species-four Gram-positive (Staphylococcus aureus, Enterococcus casseliflavus, Streptococcus pyogenes, and Streptococcus pneumoniae) and three Gram-negative (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa)-and two fungi species (Candida albicans and Candida parapsilosis). Usnic acid (UA) was used as a positive control. The ICP-MS data showed a considerable Ca content (979.766 µg/g), followed by, in decreasing order, Mg, Mn, Al, Fe, and Zn. Other elements had low levels: Ba, Cu, Pb, and Cr (3.782-1.002 µg/g); insignificant amounts (<1 µg/g) of Hg and V were also found in dUB. The trace elements Ag, As, Cd, Co, Li, Tl, Mo, Pd, Pt, and Sb were below detection limits (<0.1 µg/g). The DDM results-expressed as the size (mm) of the inhibition zone diameter (IZs)-proved that the water extract did not have any inhibitory activity on any pathogens (IZs = 0 mm). Gram-positive bacteria displayed the most significant susceptibility to all other UBDE, with Enterococcus casseliflavus showing the highest level (IZs = 20-22 mm). The most susceptible Gram-negative bacterium was Pseudomonas aeruginosa (IZs = 16-20 mm); the others were insensitive to all U. barbata dry extracts (IZs = 0 mm). The inhibitory activity of UBDE and UA on Candida albicans was slightly higher than on Candida parapsilosis.

Synthesis of gallotannin capped iron oxide nanoparticles and their broad spectrum biological applications

Green synthesized nanoparticles (NPs) have attracted enormous attention for their clinical and non-clinical applications. A natural polyphenol, gallo-tannin (GT) was used to reduce and cap the Fe2O3-NPs. GT-Fe2O3-NPs were synthesized following co-precipitation of FeCl3 and FeSO4·7H2O with GT. Fe2O3-NPs absorbed light at 380 nm. Physicochemically, Fe2O3-NPs were spherical with slight aggregation and average diameter of 12.85 nm. X-ray diffraction confirmed crystallinity and EDX revealed the elemental percentage of iron and oxygen as 21.7% and 42.11%, respectively. FT-IR data confirmed the adsorption of gallo-tannin functional groups. Multiple drug-resistant (MDR) Escherichia coli (ESβL), Pseudomonas aeruginosa (ESβL), and Staphylococcus aureus were found susceptible to 500-1000 μg GT-Fe2O3-NPs per ml. In synergy, Fe2O3-NPs enhanced the efficiency of some antibiotics. GT-Fe2O3 NPs showed significant (P ≤ 0.05) inhibition of growth and biofilm against MDR E. coli, P. aeruginosa, and S. aureus causing morphological and biofilm destruction. Violacein production (quorum sensing mediated) by C. violaceum was inhibited by GT-Fe2O3-NPs in a concentration-dependent manner with a maximum decrease of 3.1-fold. A decrease of 11-fold and 2.32-fold in fungal mycelial growth and human breast cancer (MCF-7) cell viability, respectively was evident. This study suggests a plausible role of gallo-tannin capped Fe2O3-NPs as an alternative antibacterial, antiquorum sensing, antibiofilm, antifungal, and anti-proliferative agent.

Bio-synthesized iron oxide nanoparticles for cancer treatment

Various living organisms, such as bacteria, plants, and animals can synthesize iron oxide nanoparticles (IONP). The mechanism of nanoparticle (NP) formation is usually described as relying on the reduction of ferric/ferrous iron ions into crystallized nanoparticulate iron that is surrounded by an organic stabilizing layer. The properties of these NP are characterized by a composition made of different types of iron oxide whose most stable and purest one appears to be maghemite, by a size predominantly comprised between 5 and 380 nm, by a crystalline core, by a surface charge which depends on the nature of the material coating the iron oxide, and by certain other properties such as a sterility, stability, production in mass, absence of aggregation, that have apparently only been studied in details for IONP synthesized by magnetotactic bacteria, called magnetosomes. In the majority of studies, bio-synthesized IONP are described as being biocompatible and as not inducing cytotoxicity towards healthy cells. Anti-tumor activity of bio-synthesized IONP has mainly been demonstrated in vitro, where this type of NP displayed cytotoxicity towards certain tumor cells, e.g. through the anti-tumor activity of IONP coating or through IONP anti-oxidizing property. Concerning in vivo anti-tumor activity, it was essentially highlighted for magnetosomes administered in different types of glioblastoma tumors (U87-Luc and GL-261), which were exposed to a series of alternating magnetic field applications, resulting in mild hyperthermia treatments at typical temperatures of 41-45 °C, leading to the full disappearance of these tumors without any observable side effects.