The importance and need for eco-oriented technologies has increased worldwide, which leads to an enhanced development of methods for the synthesis of nanoparticles using biological agents. This review de-scribes the current approaches to the preparation of biogenic silver nanoparticles, using plant extracts and filtrates of fungi and microorganisms. The peculiarities of the synthesis of particles depending on the source of biocomponents are considered as well as physico-morphological, antibacterial and antifungal properties of the resulting nanoparticles which are compared with such properties of silver nanoparticles obtained by chemical synthesis. Special attention is paid to the process of self-assembly of biogenic silver nanoparticles.

Background: Biological approach is becoming more popular in the protection of the environment by organic waste of agricultural holdings due to economic efficiency and absence of additional damage to the ecosystem. Microorganisms of biopreparations possess significant fermentative properties and high antagonistic activity against of many pathogenic and opportunistic bacteria and toxigenic filamentous fungi. In our study we have isolated millions of coliform bacteria and Enterococci, thousands of Salmonella, Proteus and Staphylococci in 1 g of initial substrate. After the usage of biopreparations the quantity of coliform bacteria and Enterococci was less than 10 cells/g, and no Salmonella, Staphylococcus or Proteus were found. Application of the biopreparations has prevented the loss of nutrients. Therefore, nitrogen content was higher by 50-60% than in the control. The quantity of nitrifying, ammonifying and cellulose-fermenting microorganisms increased by 15.9%, 6.6% and 15.4%, respectively. Productivity of grain and vegetable crops increased by 10-20%. An important advantage of the biopreparations usage, that also we found, is the elimination of specific odor within a couple days due to the ability of their microorganisms to assimilate nitrogen from urea and neutralize the substrate against the bacteria causing putrefaction, anaerobic processes and the emission of ammonia and hydrogen sulphide. Conclusion: The application of developed new biopreparations will allow producing high-quality environmentally friendly agricultural products.

A simple method for producing a nanocomposite based on halloysite nanotubes modified with carboxymethylcellulose and trypsin and lysozyme enzymes was developed. Fourier transform infrared spectroscopy confirmed the presence of enzymes in the samples. Chitosan-based coatings were subsequently produced from the nanocomposites. Atomic force microscopy visualization revealed the formation of globular structures consisting of enzymes and carboxymethylcellulose on the halloysite surface. An analysis of the coatings revealed a uniform distribution of halloysite throughout the matrix. The antibacterial activity of the nanocomposite containing lysozyme against Escherichia coli OP 50-1 was 47.2% and 63.9% at a concentration of 0.5 and 1 mg/mL, respectively. The antibacterial activity of the nanocomposite containing trypsin against Escherichia coli OP 50-1 was 44.4 and 55.5% at concentrations of 0.5 and 1 mg/mL, respectively. The antibacterial activity of the nanocomposite containing lysozyme against Staphylococcus aureus 6583 was 26.1 and 50.7% at concentrations of 0.5 and 1 mg/mL, respectively. The antibacterial activity of the nanocomposite containing trypsin against Staphylococcus aureus 6583 was 53.6 and 75.4% at concentrations of 0.5 and 1 mg/mL, respectively. The antibacterial activity of coatings based on chitosan and the nanocomposites containing trypsin and lysozyme against Escherichia coli OP 50-1 and Staphylococcus aureus 6583 was observed.

Antibacterial coatings are used in the food, textile, and construction industries, as well as in biotechnology and medicine. This review considers the main types of coatings that prevent surfaces from fouling with biomacromolecules and microorganisms, i.e., anti-adhesive, contact-type, release-based, multifunctional, and intelligent (“smart”) coatings. For each type of the coatings, the most relevant and efficient active substances and their action mechanisms are described. Despite the wide use of anti-adhesive surfaces and contact-type coatings, they have many drawbacks that limit the scope of their application and reduce their activity and durability. Numerous studies have shown that multifunctional and intelligent coatings have a high potential for practical application and further studies of their modification aimed at producing universal and economically advantageous coatings. The main problem of the practical application of such surfaces is the imperfection of the methods used to assess the stability and antibacterial properties of the coatings under laboratory conditions.

This review systematizes the data obtained in recent years on the application of interfacial self-assembly of halloysite nanoparticles into three-dimensional structures. Halloysite nanotubes can be used for stabilizing Pickering emulsions, microencapsuling living microorganisms, and self-assembly on the surface of human hair and hair of mammals. Mechanisms for the manifestation of the kinetic and physical properties of such structures and possible methods of their employment in medicine, cosmetology, biology, and veterinary science are characterized.