Synthesis of Colloidal Silver Using Lignosulfonates

Colloidal silver solutions can be used as catalysts for carrying out various chemical transformations of organic substances and solving the problems of disposal of toxic compounds, as well as antibacterial agents for combating pathogenic microflora, in the manufacture of lubricants and light-absorbing materials, coatings, sensors, conductive pastes, and high-performance electrode materials. The research purpose is to study the synthesis of colloidal silver using a solution of technical lignosulfonates (LST) as a stabilizer. Colloidal silver was synthesized as a result of the reduction-oxidation (redox) reaction of Ag(I) cations with glucose at 100 °C in the presence of lignosulfonates. The reaction was carried out in an alkaline medium, which is provided by the addition of ammonia water. Electronic spectroscopy was used to control the synthesis of colloidal silver. After the reaction, the solution turned dark brown and an intense absorption band with a maximum at 400 nm appeared on the electron spectra. The effects of reagent consumption and synthesis duration were studied. It was found that the optimal reagent consumption in the colloidal silver synthesis is as follows: 2.5–5 g glucose / g Ag, 0.3–1 g LST / g Ag, and 3–5 g NH3 / g Ag. The synthesis duration is 2–5 min. The resulting colloidal silver solution is stable for several months. Partial stratification without precipitation is observed during the solution storage. It is shown experimentally that the stratification is followed by a redistribution of colloidal silver particles. Electron spectroscopy confirmed the absence of colloidal silver particles in the upper layer. The reaction kinetics has been studied in experiments carried out under thermostatically controlled conditions at temperatures from 50 to 100 °C. The kinetic dependence is described by a first-order equation at the initial stage of the reaction, the duration of which depends on the temperature. The duration of the active part of the kinetic curves is 15–90 % of the total reaction time. The logarithm of the rate constant on the active section was proved to depend linearly on the reverse thermodynamic temperature (pair correlation coefficient is 0.9887). The activation energy was 47 kJ/mol. For citation: Plakhin V.A., Khabarov Yu.G., Veshnyakov V.A. Synthesis of Colloidal Silver Using Lignosulfonates. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 184–195. DOI: 10.37482/0536-1036-2021-6-184-195

Effect of voltage and anodizing time on nano colloidal silver

The objective of the present study was to investigate the effect of voltage and anodizing time on the average particle size of nano colloidal silver. The results of the zeta sizer analysis showed that the average particle size of the nano colloidal silver increased with increasing the voltage. On the other hand, anodizing time did not show a specific effect on the average particle size of the nano colloidal silver. The results also show that the samples prepared at 20 V with anodizing time of 2 hours exhibits an average particle size of less than 100 nm, which is potential to be used as disinfectant spray. Also, it shows that electrolysis is a suitable method to produce nano colloidal silver.

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.

Efficacy in degradation of carcinogenic pollutant sulforhodamine B by green synthesized silver nanoparticles

Colloidal Silver nano-particles were grown at room temperature using leaf extract of Ocimum tenuiflorum. The silver nanoparticles suspended in the solution were found to be stable for over a period of 2 months. Structural, optical and photo catalytic behavior of the suspended silver (Ag) nano-particles (NPs) was characterized. From TEM analysis the size of the silver nanoparticles was estimated to be 25–30 nm. Our findings suggest that the ratio between the molarity of AgNO3 and the volume of leaf extract does not have any role in controlling the size of the Ag nano-particles. These green synthesized Ag nano-particles exhibit degradation of the carcinogenic organic pollutant sulforhodamine B in absence of light.

Silver nanoparticle based alcohol sensor manufacturing training for detection of halal drinks

Nowadays, halal drinks are one of the sectors that get the attention of various parties. Alcohol in beverages is important in determining the halalness of a beverage. Halal detection can be done using chemical sensors. In the Pharmacy Department, knowledge of analysis using sensors is rare. Therefore, this community service program was carried out to introduce qualitative methods of quick and simple alcohol analysis. The participants are students of the Pharmacy Department of STIKES Anwar Medika in Sidoarjo City. Participants are communities engaged in the health sector who have an interest in halal and how to make sensors for halal testing. This program is implemented by making a video on how to make a chemical sensor for alcohol detection. The chemical sensor is a paper-immobilized colloidal silver-based chemical sensor that is easy to apply in various conditions. Based on the results of the color change produced on the filter paper, from green to bluish which indicates that the food or beverage sample contains alcohol. Based on the questionnaire, participants expressed satisfaction with the increase in knowledge about additional tools that are easy and fast to detect alcohol.

Production of Feminized Seeds of High CBD Cannabis sativa L. by Manipulation of Sex Expression and Its Application to Breeding

The use of the cannabis plant as a source of therapeutic compounds is gaining great importance since restrictions on its growth and use are gradually reduced throughout the world. Intensification of medical (drug type) cannabis production stimulated breeding activities aimed at developing new, improved cultivars with precisely defined, and stable cannabinoid profiles. The effects of several exogenous substances, known to be involved in sex expressions, such as silver thiosulfate (STS), gibberellic acid (GA), and colloidal silver, were analyzed in this study. Various concentrations were tested within 23 different treatments on two high cannabidiol (CBD) breeding populations. Our results showed that spraying whole plants with STS once is more efficient than the application of STS on shoot tips while spraying plants with 0.01% GA and intensive cutting is ineffective in stimulating the production of male flowers. Additionally, spraying whole plants with colloidal silver was also shown to be effective in the induction of male flowers on female plants, since it produced up to 379 male flowers per plant. The viability and fertility of the induced male flowers were confirmed by fluorescein diacetate (FDA) staining of pollen grains, in vitro and in vivo germination tests of pollen, counting the number of seeds developed after hybridization, and evaluating germination rates of developed seeds. Finally, one established protocol was implemented for crossing selected female plants. The cannabinoid profile of the progeny was compared with the profile of the parental population and an improvement in the biochemical profile of the breeding population was confirmed. The progeny had a higher and more uniform total CBD (tCBD) to total tetrahydrocannabinol (tTHC) ratio (up to 29.6; average 21.33 ± 0.39) compared with the original population (up to 18.8; average 7.83 ± 1.03). This is the first comprehensive report on the induction of fertile male flowers on female plants from dioecious medical cannabis (Cannabis sativa L.).