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Abstract Biosynthesized metal nanoparticles have unique properties and are being actively studied as potential antimicrobial agents against resistant pathogens. The “green” synthesis of silver nanoparticles and their conjugate with the antibiotic ceftriaxone, carried out using the aqueous extract of Chaenomeles japonica leaves as a biological matrix, is reported here for the first time. UV-visible spectra confirmed the creation of biosynthesized silver nanoparticles (Ch-AgNPs) and their conjugates with ceftriaxone (Ch-AgNPs-Cfx), which were characterized by surface plasmon resonance absorption peaks at 475 and 478 nm, respectively. Fourier transform infrared spectrum analysis revealed the participation of hydroxyl and carboxyl functional groups of phenolic and aromatic compounds, flavonoids, terpenoids, alcohols, and carboxylic acids of the plant extract in the process of bioreduction of Ag+ to Ag0 as well as the involvement of carbonyl and amine groups of proteins in blocking and stabilization silver nanoparticles. The antimicrobial activity of Ch-AgNPs, Ch-AgNPs-Cfx, and ceftriaxone was evaluated using a disk diffusion assay against Pseudomonas aeruginosa strain resistant to some cephalosporins. Studies have shown a dose-dependent inhibition of P. aeruginosa by Ch-AgNPs and Ch-AgNPs-Cfx in the range of 2.5–20 μg/disk, which exceeded the activity of ceftriaxone at the same doses, which characterizes both types of biosynthesized nanoparticles as promising bactericidal agents. Further research on Ch-AgNPs and Ch-AgNPs-Cfx may be aimed at creating effective means to reduce the antibiotic doses without losing antibacterial activity against resistant pathogens.

ABSTRACT The green synthesis of metal nanoparticles (NPs) has garnered significant attention due to its simplicity, cost-effectiveness, and environmental sustainability. Gold NPs (AuNPs) and silver NPs (AgNPs) are widely employed across various industries, agriculture, and medicine owing to their unique physicochemical properties. This study explores the feasibility of synthesizing metal NPs through green methods using ethanolic (70%) extracts from Artemisia annua hairy roots. These extracts were found to contain reducing agents, primarily phenolic compounds, as identified by HPLC and MALDI-MS analyses. The phenolic compounds included hydroxybenzoic acids (e.g. p-coumaric and gallic acids) and hydroxycinnamic acids (e.g. caffeic acid and its derivatives such as chlorogenic, dicaffeoylquinic, and rosmarinic acids). The synthesis and structural characteristics of AuNPs and AgNPs were systematically compared. AgNPs formed a stable colloidal solution over extended periods, while AuNPs exhibited instability due to significant NP aggregation and precipitation. Furthermore, the photocatalytic activities of these NPs in the degradation of Methylene Blue were evaluated. AuNPs demonstrated substantial photocatalytic activity, whereas AgNPs exhibited negligible catalytic effects. This study highlights the potential and limitations of A. annua hairy root extracts in the biosynthesis of AuNPs and AgNPs, providing insights into their structural and functional differences.

Abstract Since the nanoscale in combination with luminescent properties and prospective applications in different fields of optoelectronics and biomedicine is stimulating a growing interest towards research in the area of cadmium telluride (CdTe) quantum dots (QDs), the method of “green” synthesis of CdTe QDs with the use of the Pleurotus ostreatus mycelium culture as a biological matrix has been developed. The study of their physical and chemical characteristics has shown that the synthesized CdTe QDs are characterized by a crystalline structure and a predominantly spherical morphology and are 3–8 nm in size with the luminescence maximum within the 340–370 nm range. The study of their effects on different types of mammalian cells has shown that CdTe QDs have dose-dependent effects on mouse endothelial cells and human and rat erythrocytes, T- and B-lymphocytes, colorectal cancer cells (Colo 205), and human breast cancer cells (MCF-7). In particular, suppression of proliferative indices of endotheliocytes and an increase in the count of dead cells were observed, which indicates the cytotoxic action of nanocrystalline CdTe and its antiproliferative effect on endothelial cells. At the 5 µM concentration, CdTe QDs exhibited hemolytic activity, due to their action on erythrocytes, and affected adhesive contacts and cancer cell survivability. At the same time, human breast cancer cells (MCF-7) were more sensitive to their action. The data obtained are exclusively important for the understanding of mechanisms underlying the toxicity of CdTe QDs and for their future application in biological and biomedical research.