The development of ‘green’ technologies in nanoparticle synthesis is of considerable importance to broaden their biological applications. Cadmium sulphide nanoparticles are considered very promising in applied chemistry, bioscience and medicine. The aim of this study was to develop an efficient, easily reproducible and environmentally friendly method for biosynthesis of cadmium sulphide quantum dots based on the usage of mycelium of the basidiomycete fungus Pleurotus ostreatus. By incubating P. ostreatus mycelium with inorganic cadmium sulphate and sodium sulphide, we synthesized stable luminescent CdS nanocrystals. They showed absorption peaks at 453 nm (ultraviolet–visible spectrometry) and a main luminescent peak at 462 nm. Transmission electron microscopy revealed that the obtained quantum dots were of a spherical shape and predominantly from 4 to 5 nm in size. The electron diffraction pattern confirmed the wurtzite crystalline structure of the synthesized cadmium sulphide quantum dots. The obtained results confirm for the first time that the system based on basiodiomycete fungi could be considered promising for synthesizing semiconductor quantum dots.

Ag-based quantum dots (QDs) are semiconductor nanomaterials with exclusive electrooptical properties ideally adaptable for various biotechnological, chemical, and medical applications. Silver-based semiconductor nanocrystals have developed rapidly over the past decades. They have become a promising luminescent functional material for in vivo and in vitro fluorescent studies due to their ability to emit at the near-infrared (NIR) wavelength. In this review, we discuss the basic features of Ag-based QDs, the current status of classic (chemical) and novel methods (“green” synthesis) used to produce these QDs. Additionally, the advantages of using such organisms as bacteria, actinomycetes, fungi, algae, and plants for silver-based QDs biosynthesis have been discussed. The application of silver-based QDs as fluorophores for bioimaging application due to their fluorescence intensity, high quantum yield, fluorescent stability, and resistance to photobleaching has also been reviewed.

CdS nanoparticles have a great potential for application in chemical research, bioscience and medicine. The aim of this study was to develop an efficient and environmentally-friendly method of plant-based biosynthesis of CdS quantum dots using hairy root culture of Linaria maroccana L. By incubating Linaria root extract with inorganic cadmium sulfate and sodium sulfide we synthesized stable luminescent CdS nanocrystals with absorption peaks for UV-visible spectrometry at 362 nm, 398 nm and 464 nm, and luminescent peaks at 425, 462, 500 nm. Transmission electron microscopy of produced quantum dots revealed their spherical shape with a size predominantly from 5 to 7 nm. Electron diffraction pattern confirmed the wurtzite crystalline structure of synthesized cadmium sulfide quantum dots. These results describe the first successful attempt of quantum dots synthesis using plant extract. 81.07.Ta; 81.16.-c; 81.16.Rf

The review considers involvement of nitric oxide (NO) in regulation of basic physiological processes underlying growth, development, and senescence in plants. The NO sources in plants, as well as direct and indirect NO signaling mechanisms are also reviewed. Particular attention is paid to the role of this secondary messenger in plant responses to various abiotic stresses, such as mechanical injury, salinity, drought, UV irradiation, high and low temperatures, ozonation, hypoxia, the impacts of heavy metals and herbicides. The role of NO in the hypersensitive response and in a systemic response upon plant infection with invasive pathogens is described.