Silver in different forms has been widely used in medicine for curing disease and help promote wound healing since early times. A common form of silver that is used to treat infections is silver nitrate. This was formerly used as a prophylactic treatment of ophthalmia neonatorum in infants, but was discontinued because of the risk of blindness due to silver nitrate toxicity.

Recent advancement in technology has introduced silver nanoparticles into the medical field. As studies of silver nanoparticles improve, several silver nanoparticles medical applications have been developed to help prevent the onset of infection and promote faster wound healing.

The coating of medical instruments is one recent silver nanoparticles medical application in study. A combination of the bacteriolytic action of lysozyme and biocidal activity of silver nanoparticles were synthesized together as a form of antimicrobial coating on medical instruments. These were applied to surfaces of stainless surgical steel blades and needles through an electrophoretic process. The efficacy of the antimicrobial coatings was tested in an environment that mimics the normal use of the surgical instruments. The environment was an in vitro lytic assay, in which punctures and incisions were done into an agar that has been inoculated with bacteria. Bacterial cell destruction was reported on the areas where the surgical instruments coated with silver nanoparticles came in contact with. This means that the antibacterial properties of the silver nanoparticles were transferred to the surface where the surgical instruments came in contact with, while the same antibacterial properties were retained in the blades and needles.

The treated instruments were observed to have a powerful bactericidal action against Klebsiella pneumoniae, Bacillus anthracis Sterne, and Bacillus subtilis for 1 hour and 30 minutes. Staphylococcus aureus and Acinetobacter baylyi were contained for 3 hours.

Use of nanopartices in catheters is another example of a medical application for silver nanoparticles that is gaining popularity. A study entitled “Antimicrobial Surface Functionalization of Plastic Catheters by Silver Nanoparticles” was published in The Journal of Antimicrobial Chemotherapy (Roe et. al.) supported the value of using silver as a coating on catheters.

Infections due to catheter use are common in hospitals, especially when it comes to in-dwelling catheters.  A silver coating was proven to be effective against methicillin-resistan Staphylococcus aureus (MRSA), a common pathogen that causes infections in surgical sites. The cited study observed the action of microbial and biofilm formations in catheter-related infections. A layer of sustained-release silver nanoparticles were applied on the catheters that emit antimicrobial properties for a 10-day period. Major in vitro antimicrobial activity was noted in the coated catheters, as well as inhibition of biofilm formation of several strains of bacteria including Escherichia coli, Enterococcus, Staphylococcus aureus. This finding is quite significant as patients that have in-dwelling catheters are at high risk in developing urinary tract infections due to prolonged use .

Among silver nanoparticles medical applications which may soon hit hospitals is in the treatment of face masks to give them antimicrobial properties.

Face masks in hospitals have all the necessary elements for bacterial proliferation. Masks treated with silver nanoparticles even at low concentrations were proven to be effective against any bacteria that attach themselves to the surface of the mask, including Staphylococcus aureus and Escherichia coli. This finding is significant for this shows that front-line healthcare providers will have active protection against microorganisms during exposure to infectious agents. The use of silver nanoparticles along with other antimicrobial agents will help prevent the formation of resistant bacterial strains.

It is important that any antimicrobial agents used in the hospital setting have little or no adverse effects against on any organic material. During the study, it was observed that the presence of serum has an effect on the antimicrobial property of silver nanoparticles by resulting in a slight inhibition of the property.

The success of silver nanoparticles against bacterial growth is due to the damage of the plasma membrane or bacterial enzymes. This results to a morphological distortion of the bacterial cells, leading to impairment of bacterial metabolism and escape of cytoplasmic substance to the surroundings. To ensure a uniform coating of silver nanoparticles on the mask, oleophobol C was added. Oleophobol C contains no antimicrobial properties, thereby not affecting the antimicrobial action of silver nanoparticles.

Frontline healthcare providers need several protective methods to screen themselves from infective agents and also to prevent spreading infection to others. It is noted that constant changing of personal protective equipments is not always possible, especially when supplies are limited. Application of silver nanoparticles can prevent accumulation of bacterial contaminants from accumulating in the mask, further protecting the wearer from other infections. Sadly, this experimental study is highly limited due to very low number of participants. Those who have used the treated masks have shown no allergic reaction to the new coating.

There are other silver nanoparticles medical applications that are being utilized in hospitals. Several studies and experiments are being conducted with the use of silver nanoparticles to promote wound healing and prevent infection through topical applications. Wound dressings are now made with silver nanoparticles for local treatment of ulcers of the limbs as well as treatment of deep second degree and third degree burns. The dressings can either be used in a hospital setting or applied in an ambulatory procedure. The nanoparticles work by coagulating and dissecting intracellular compounds, resulting in cellular breakdown and destruction. Significant levels of antibacterial activity were observed even in the presence of low silver nanoparticle concentrations.

Some other studies are being conducted cautiously as there are several reported adverse reactions when silver nanoparticles are introduced. These adverse reactions include, but are not limited to allergic reactions, argyria and staining. Argyria is a bluish discoloration of the skin caused by excessive exposure to silver compounds. The condition usually resolves itself within 2-14 days after cessation of therapy, but in some case can be permanent. Research is also being conducted to see how these adverse reactions can be treated or avoided while undergoing silver nanoparticles therapy.