• Broad Spectrum Antimicrobial activity
• Eco-friendly, degrading to water and oxygen
• Multifunctional as it finds a wide range of applications
• Multimedia sanitation (Air, Water, Soil, Surface)
• Nontoxic on humans and plants
• Cold sterilant, not requiring any heat for disinfection
• Non foaming nature
• Does not require flushing with water
• Does not emit toxic harmful fumes like as formalin, bromine and other aldehydes.
• Undergoes chain oxidation reaction, needs a stabilizer to break even
• Rapid action on a short contact period with a wide range of effectiveness.

Properties of silver that synergize the activity of hydrogen peroxide

Oligodynamic function: Ionic Ag has a toxic effect on bacterial cells. It denaturizes the enzymes of the target cell/ organism by binding to their reactive thiol groups, and precipitating as silver sulfides, resulting in their inactivation.

Stabilizer function: Addition of silver stabilizes the otherwise unstable hydrogen peroxide, preventing the slow decomposition of the same. The Ag+2 ions keep the O-2 ions.

Activator function:  On contact with organic material (microorganisms), the silver starts to activate the hydrogen peroxide. The capacity of silver to activate the hydrogen peroxide is preserved until the hydrogen peroxide comes into contact with organic material (microorganisms); Following this, any unused hydrogen peroxide deactivates and returns to its stabilized situation. Known as the ‘Store and Depot’ action, this accounts for an excellent disinfection for a longer period of time.

This synergy of hydrogen peroxide and nano silver is so effective that it makes Silver Hydrogen Peroxide a biocide nearly twenty times more powerful than hydrogen peroxide alone.

Nano Silver Technology – Why?

Nano-Silver Technology has flourished in the recent times, prompting its expanded applications in daily life. Nano-Ag particles in comparison to other metals, show higher lethality for microorganisms and lower for mammalian cells (people). A nano-meter is almost one-billionth of a meter, and nano-Ag particles range from 1nm to 100nm in size, permitting them to reach places that alternate structures cannot. Likewise, nano-Ag is more effective than AgNO3 on account of their expansive surface area to volume ratio, increasing the number of particles discharged per unit mass of silver, thereby a greater amount of ions are involved in the cell destruction process. 

Advantages of silver nanoparticles over conventional silver nitrate

Silver nanoparticles attaches itself to the surface of the cell membrane, interrupting permeability and metabolic pathways,They not only interact with the membrane surface, but can also penetrate the bacterial cell membrane, In addition, they can bind to the DNA inside the microbial cells, preventing its replication, It has been discovered that nano-Ag particles can damage the bacterial cell membrane structure and reduce the activity of some membranous enzymes

Functions of Nano-Silver

• Stabilizes the hydrogen peroxide in this silver peroxide blend
• Activates the hydrogen peroxide only after dilution enhancing longevity of hydrogen peroxide and silver
• Destroys further production of enzymes required for cellular metabolism
• DNA structure is rearranged and destroyed, rendering microbes incapable of multiplying
• Benefits of (Nano Silver Hydrogen Peroxide based Biodegradable Disinfectant)
• Cold sterilant (does not require any heat for disinfection)
• Effective over a large range of microorganisms
• Efficient Fungicide, Antibiotic, Virucide, Nematicide
• Owing to its non-foaming nature, it is suitable for both cleaning and disinfecting
• Eco friendly, biodegradable, colourless, odourless product
• Non carcinogenic and non-mutagenic in nature, with no danger of microbial resistance
• Non-polluting, non-staining in nature
• Does not emit any harmful fumes (unlike chlorine, bromine, formalin, and aldehydes)
• Multimedia sanitation (air, water, soil, surface)
• Stably works over a wide range of pH and temperature
• This silver peroxide destroys biofilms
• Rapid sterilization unlike other traditional methods
• Does not change/ alter any physical properties of the medium
• Non-flammable, minimizing transportation and storage risks
• High thermo-stability
• Easy handling and dosing
• Free of carcinogenic aldehydes
• No gaps in efficacy
• Silver peroxide works on a short contact time
• Long lasting disinfection with no toxic residues

Introduction to Hydrogen Peroxide

Hydrogen peroxide (H2O2) is a colourless liquid, slightly more viscous than water. It is the simplest member of the class of peroxides (compounds with an oxygen-oxygen single bond). Dominated by the nature of its highly unstable peroxide bond, hydrogen peroxide is known for its strong oxidizing properties.

First recognized by a French scientist back in 1818. Owing to its unstable nature, all efforts to separate it from water had failed, until 1894, when it was first extracted using a process called vacuum distillation.

Often described as “water with an extra oxygen atom”, a description which may give the wrong impression of the similarity between the two compounds. It is handled as a dilute solution (household grades are typically 3-6%), because pure hydrogen peroxide will explode if heated to boiling, it causes serious contact burns to the skin, and on contact may set materials ablaze.

Pure hydrogen peroxide freezes at -0.43° C (+31.3 F) and boils at 150.2° C (302 F); it is denser than water and is soluble in it in all proportions.

Used mostly for bleaching cotton and other textiles, chemical manufacturing, as a rocket propellant, and for cosmetic and medicinal uses, with its aqueous solutions of various strengths.

Composed only of water and oxygen, hydrogen peroxide has been known as the world’s safest sanitizer. 2H2O2 --> 2H2O + O2. Like ozone, it is known for killing microorganisms by oxidizing them, its mode of action is best explained as a controlled burning process. In most of its reactions, hydrogen peroxide oxidizes other substances, although it is itself oxidized by a few compounds such as potassium permanganate. Nontoxic in nature, yet hydrogen peroxide is highly unstable, making it ineffective after a short span of time.

Introduction to Silver (as Antimicrobial)

Silver is a chemical element by the symbol Ag. Occurring naturally in its pure, free form (native silver), an alloy with gold and other metals, and in minerals such as argentite and cholangitis. Most silver is produced as a by-product of copper, gold, lead, and zinc refining.

History

Renowned for many centuries for its antimicrobial properties to many cultures all around the world. The Phoenicians knew well to store water, wine and vinegar in silver coated vessels to reduce microbial contamination. Silver dollars were put into milk bottles to keep the milk fresh.

In 1884, it became a common practice to administer drops of aqueous silver nitrate to new-born’s eyes to prevent the transmission of Neisseria gonorrhoeae from infected mothers to children during childbirth (Silvestry-Rodriguez et al., 2007).

In 1893, the antibacterial effectiveness of various metals were noted and this property was termed as the oligodynamic effect. Out of all the metals with antimicrobial properties, silver has the most effective antibacterial action with the least toxicity to animal cells (Guggenbichler et al., 1999). It was used for treating wounded soldiers in World War I.

Once antibiotics were discovered, the use of silver as a bactericidal agent decreased. However, with the emergence of antibiotic-resistant strains such as CA-MRSA and HA-MRSA, the flesh-eating bacteria and the increasing antibiotic resistance, there has recently been an improved interest in using silver as an antibacterial agent.

The antimicrobial properties of silver have been known for centuries, but we have only recently begun to understand the mechanisms by which silver inhibits bacterial growth.

Action Mechanisms, Ionized silver

Silver is inert in its non-ionized form; in order for silver to have any antimicrobial properties, it must be in its ionized form. Thus, all forms of colloidal silver or silver containing compounds with observed antibacterial properties are in one way or another sources of Ag+ ions; which may be incorporated into the substance and released slowly over time.

Entering the cell

An Ag ion simply appears to be a particle with +1 surface charge. It is possible that they gain access to the interior of the cell through transmembrane proteins that in general function to transport ions other than silver ions. Transmembrane proteins, for example, CopB-ATPase from Enterococcus hirae has the capacity to transport silver particles despite the fact that it is perceived as a copper transporter. This demonstrates there are routes for silver transportation even without its transporters.

Protein inactivation

It is thought that silver atoms bind to thiol/ sulfhydryl groups (-SH) in enzymes, resulting in their inactivation. Forming stable Ag-S bonds with thiol-containing compounds in the cell membrane which are involved in transmembrane energy generation and ion transportation. Silver also catalyzes the reaction between two oxygen molecules and hydrogen atoms, releasing water as a product, and the two thiol groups are covalently bonded through a disulfide (R-S-S-R) bond. This catalyzed formation of disulfide bonds could possibly change the shape of cellular enzymes, consequently hindering their function. The silver-catalyzed formation of disulfide bonds can alters the protein structure, inactivating key enzymes needed for cellular respiration. Binding to the 30S ribosomal subunit, it even deactivates the ribosomal complex.

DNA Association

It was suggested that Ag+ enters the cell and joins itself between the purine and pyrimidine base sets, upsetting the hydrogen holding between the two hostile to parallel strands and denaturing the DNA particle. Yet to be proved, but it has been demonstrated that silver particles do partner with DNA once they enter the cell.

Different forms of Silver administration

Silver salts: Salts such as silver nitrate (AgNO3), even precipitated colloidal silver are effective at providing a large quantity of Ag ions for a prolonged period of time.

Silver zeolite: Zeolite is a porous medium of sodium aluminosilicate, another much used form of administration, can hold a large amount of silver ions in its micropores (Monteiro et al., 2009). Silver ions are released in exchange to other cations in the solution.

Silver nanoparticles: Simple synthesis and highly effective bactericidal, fungicidial, virucidal and other microbicidal properties make them very attractive in silver administration.

Toxicity

Argyria is the main known reaction of high exposure to or ingestion of silver. In spite of bringing on a dark blue skin discolouration, it is not viewed as perilous health-wise. In light of human case reports and creature tests, WHO has advised 10 g of silver to be lifetime NOAEL (No Observable Adverse Effect Level).

The EPA has set an auxiliary most extreme contaminant level for silver at 0.1 mg/L. For the most part unenforced, these levels are just given as proposals to the administration of open water frameworks. The purpose behind this non-implementation is on the grounds that these contaminants have been found to just aim aesthetic effects, such as the scent or taste of drinking water, cosmetic effects, which are undesirable however not destructive.