Search

The most critical group of all includes multidrug resistant bacteria that pose a particular threat in hospitals, as they can cause severe and often deadly infections. Modern medicine still faces the difficult task of developing new agents for the effective control of bacterial-based diseases. The targeted administration of nanoparticles can enhance the efficiency of conventional pharmaceutical agents. However, the interpretation of interfaces' interactions between nanoparticles and biological systems still remains a challenge for researchers. In fact, the current research presents a strategy for using ZnO NPs immobilization with ampicillin and tetracycline. Firstly, the study provides the mechanism of the ampicillin and tetracycline binding on the surface of ZnO NPs. Secondly, it examines the effect of non-immobilized ZnO NPs, immobilized with ampicillin (ZnONPs/AMP) and tetracycline (ZnONPs/TET), on the cells' metabolism and morphology, based on the protein and lipid profiles. A sorption kinetics study showed that the antibiotics binding on the surface of ZnONPs depend on their structure. The efficiency of the process was definitely higher in the case of ampicillin. In addition, flow cytometry results showed that immobilized nanoparticles present a different mechanism of action. Moreover, according to the MALDI approach, the antibacterial activity mechanism of the investigated ZnO complexes is mainly based on the destruction of cell membrane integrity by lipids and proteins, which is necessary for proper cell function. Additionally, it was noticed that some of the identified changes indicate the activation of defense mechanisms by cells, leading to a decrease in the permeability of a cell's external barriers or the synthesis of repair proteins.

This research presents, for the first time, the potential of the Lactobacillus paracasei LC20 isolated from sweet whey as a novel, effective and accessible source for post-cultured ZnO nanocomposites synthesis. The obtained nanocomposites were subjected to comprehensive characterization by a broad spectrum of instrumental techniques. Results of spectroscopic and microscopic analysis confirmed the hexagonal crystalline structure of ZnO in the nanometer size. The dispersion stability of the obtained nanocomposites was determined based on the zeta potential (ZP) measurements—the average ZP value was found to be −29.15 ± 1.05 mV in the 7–9 pH range. The ZnO nanocomposites (NCs) demonstrated thermal stability up to 130 °C based on the results of thermogravimetric TGA/DTG) analysis. The organic deposit on the nanoparticle surface was recorded by spectroscopic analysis in the infrared range (FT-IR). Results of the spectrometric study exhibited nanostructure-assisted laser desorption/ionization effects and also pointed out the presence of organic deposits and, what is more, allowed us to identify the specific amino acids and peptides present on the ZnO NCs surfaces. In this context, mass spectrometry (MS) data confirmed the nano-ZnO formation mechanism. Moreover, fluorescence data showed an increase in fluorescence signal in the presence of nanocomposites designed for potential use as, e.g., biosensors. Despite ZnO NCs’ luminescent properties, they can also act as promising antiseptic agents against clinically relevant pathogens. Therefore, a pilot study on the antibacterial activity of biologically synthesized ZnO NCs was carried out against four strains (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) by using MIC (minimal inhibitory concentration). Additionally, the colony forming units (CFU) assay was performed and quantified for all bacterial cells as the percentage of viable cells in comparison to a control sample (untreated culture) The nanocomposites were effective among three pathogens with MIC values in the range of 86.25–172.5 μg/mL and showed potential as a new type of, e.g., medical path or ointment formulation.

This research presents, for the first time, the potential of the Lactobacillus paracasei LC20 isolated from sweet whey as a novel, effective and accessible source for post-cultured ZnO nanocomposites synthesis. The obtained nanocomposites were subjected to comprehensive characterization by a broad spectrum of instrumental techniques. Results of spectroscopic and microscopic analysis confirmed the hexagonal crystalline structure of ZnO in the nanometer size. The dispersion stability of the obtained nanocomposites was determined based on the zeta potential (ZP) measurements—the average ZP value was found to be −29.15 ± 1.05 mV in the 7–9 pH range. The ZnO nanocomposites (NCs) demonstrated thermal stability up to 130 °C based on the results of thermogravimetric TGA/DTG) analysis. The organic deposit on the nanoparticle surface was recorded by spectroscopic analysis in the infrared range (FT-IR). Results of the spectrometric study exhibited nanostructure-assisted laser desorption/ionization effects and also pointed out the presence of organic deposits and, what is more, allowed us to identify the specific amino acids and peptides present on the ZnO NCs surfaces. In this context, mass spectrometry (MS) data confirmed the nano-ZnO formation mechanism. Moreover, fluorescence data showed an increase in fluorescence signal in the presence of nanocomposites designed for potential use as, e.g., biosensors. Despite ZnO NCs' luminescent properties, they can also act as promising antiseptic agents against clinically relevant pathogens. Therefore, a pilot study on the antibacterial activity of biologically synthesized ZnO NCs was carried out against four strains (Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa) by using MIC (minimal inhibitory concentration). Additionally, the colony forming units (CFU) assay was performed and quantified for all bacterial cells as the percentage of viable cells in comparison to a control sample (untreated culture) The nanocomposites were effective among three pathogens with MIC values in the range of 86.25–172.5 μg/mL and showed potential as a new type of, e.g., medical path or ointment formulation. [ABSTRACT FROM AUTHOR]