Manufacturing silver nano-coating currencies to prevent the bacteria growing on the surface of currency

Abstract This study evaluated the level of contamination and pattern of organisms found on local currencies of Iraq and the antibacterial effects of silver nanoparticle (AgNPs) coating currencies in vitro. Local currencies and US dollar notes were collected and individually placed in a sterile petri plates containing Todd hewit broth incubated at 37 °C in a rotary shaker for 2 h. All the individual bacterial colonies were identified using PCR for amplifying the 16S rRNA genes. Green synthesis of AgNPs was followed as described earlier and in a dish containing a solution of AgNPs and ammonia; AgNPs was impregnated in the cellulose matrix of notes. All sterilized coated or uncoated notes were subjected for contamination of pathogens such as MRSA, VRE, ESBL E. coli, and MDRAB counting colony-forming units. A total number of 17 different bacteria were isolated from currencies of Iraq and dollars. The percent of contamination was high in local Iraqi notes than dollars notes. Many of these Iraqi notes (n = 22) showed growth of at least two bacterial species. Gram positive organisms dominated the bacterial population. Coating of notes with AgNo3 led to a less counts of organisms. Coating of nanoparticle was more effective on control of MRSA, VRE and to a lower extent E. coli. Silver which is commonly used in health products including eatable can be an alternative as a coating agent. We recommend further studies with diverse microbial contamination to enrich the information on the subject. A variety of other nanoparticles can be tested to establish a cheap and proper material which can be used for this purpose.