Assessment of the prospect for the use of colloidal silver nanoparticles for inactivation of Helicobacter pylori

Background. The growth of antibiotic resistance of Helicobacter pylori, a microorganism significant in the development of gastrointestinal diseases and inflammatory periodontal diseases, makes us think about the search for new approaches to the eradication of the microorganism. One solution to this problem may be to develop immunobiological preparations based on microorganisms inactivated with colloidal silver nanoparticles (CSNPs).The aim. To evaluate the inactivating ability of colloidal silver nanoparticles in vitro and in vivo with respect to H. pylori to determine the possibility of their use in the development of a specific immunobiological preparation.Materials and methods. The study design consisted in sequential execution of the steps of synthesis of colloidal silver nanoparticles with an assessment of the conditionality of the prepared preparations; isolating and identifying pure H. pylori culture; inactivation of H. pylori by synthesized silver nanoparticles; evaluation of the result of H. pylori inactivation in vitro and in vivo.Results. The conditionality of the synthesized colloidal silver nanoparticles of size 30 ± 3 nm, obtained using a step-by-step technique, was estimated by electron microscopy. Testing the inactivating activity of CSNPs on H. pylori showed that their effect on the culture for 3 hours at a ratio of volumes of CSNPs and 1:1 culture leads to a gradual decrease in the concentration of the microorganism until its complete death and lack of growth on the fifth passage. During the evaluation of the effect of CSNPs on H. pylori, it was shown that the inactivated culture retains its cultural and tinctorial properties; alters morphological properties and biochemical activity; becomes more sensitive to antibiotics and L. acidophilus; ceases to establish in the body of mice with an immunosuppression condition.Conclusions. Proposed method of synthesis of silver nanoparticles with proven inactivating activity against H. pylori can become a stage of biotechnological process of development of vaccine preparation both on the basis of given microorganism and in complex with CSNPs possessing multilevel antimicrobial effect, antioxidant and immunomodulating activity.

Effect of the magnetic field on the synthesis of colloidal silver and gold nanoparticles by laser ablation in bidestilated water

The effect of magnetic field of 0.3 T on the concentration, distribution of sizes in suspension and zeta potential of colloidal gold and colloidal silver nanoparticles, obtained by considering the pulsed laser ablation in double distilled water was studied. The magnetic field was transverse to the direction of incidence of the laser radiation and parallel to the surface of a submerged target. An Nd: YAG laser was used (1064 nm in wavelength, 10 ns in duration, repetition rate of 10 Hz and 37 mJ of energy) to ablate targets. The colloids were characterized by inductively coupled plasma optical emission spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering and zeta potential. Concentration analysis suggested that applying magnetic field of 0.3 T during nanoparticle synthesis leads to higher concentration. Applying magnetic field led to an eleven percent increase in the concentration of the colloid with gold nanoparticles and a five percent increase in the concentration of the colloidal silver nanoparticles. The absorption spectra suggested the presence of spherical nanoparticles. When analyzing the effect of the magnetic field on the hydrodynamic size distribution of the nanoparticles and the zeta potential of the colloids, no significant changes were evidenced. The magnetic confinement of the plasma induced by laser ablation caused changes in the characteristics of the colloids.

Synthesis of Colloidal Silver Nanoparticles in Various Liquid Media Using Pulse Laser Ablation Method and Its Antibacterial Properties

The silver nanoparticles (AgNPs) have been applied as an antibacterial agent in consumer products, cosmetics, and food industries. In this present work, AgNPs were synthesized in various mediums of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and chitosan using the pulse laser ablation synthesis method. Experimentally, a pulse Nd:YAG laser beam (1064 nm, 7 ns, 30 mJ) was directed using a silver mirror and focused using a quartz lens with a focal length of 30 mm on a silver metal plate placed in a petri dish containing liquid mediums for 120 min to produce colloidal silver nanoparticles. The results certified that All AgNPs have a spherical shape with polydisperse size in all media, including PVP, PEG, and chitosan. The smallest AgNPs have been produced in PVP medium with an averaged smallest size of 11.62 nm. Based on this result, PVP is the preferred medium to produce AgNPs with the smallest size and good stability. The produced silver nanoparticles have been successfully employed as an antibacterial agent, which is experimentally demonstrated by using Escherichia coli and Staphylococcus aureus. The result certified that the produced silver nanoparticles could effectively kill the bacteria with a killing percentage of 99.6 to 100%.