# Silver Nanowires: Synthesis, Antibacterialativity and Biomedical Applications
## 5 Emerging Biomedical Applications of Silver Nanowires
### Surface Coating of Medical Devices  
In an attempt to reduce hospital-generated infections linked to contamination of work surfaces and use of invasive devices such as catheters, many researchers also explored the use of AgNPs as components of surface coating materials. For applications in flexible electronics, AgNPs have been dispersed in a variety of polymeric materials, with a view to future biomedical applications [PERSON] et al. investigated the effects of AgNPs dispersion in chitosan films [PERSON] et al. (2018). Chitosan is a safe and biocompatible polysaccharide of renewable origin used in numerous biomedical applications; therefore, exploring its physicochemical compatibility with AgNPs could open new possibilities for the use of the metal nanostructures in drug delivery, wound healing, medical devices, etc. The bio-based hybrid films were formed by mixing soft-template synthesized AgNPs with chitosan solution followed by casting [PERSON] et al. (2018). Disc diffusion experiments showed that these hybrid films were active against _E. coli_ and _B. subtilis_, confirming that AgNPs can bestow antibacterial properties to biocompatible composite films. Environmentally friendly composite films have also been produced by blending AgNPs with konjac glucomanan (KGM) active against _E. coli_ and _S. aureus_[PERSON] et al. (2018). Taken together these two studies show activity against both Gram-positive and Gram-negative bacteria. Moreover, the zones of inhibition reported for silver nanowires-KGM films for _E. coli_ were much greater than those for silver nanowire-chitosan-based hybrid films, suggesting that the different components of the films may change or alter the effectiveness of the silver nanowires against Gram-negative bacteria. Furthermore, in both studies, the mechanical properties of the hybrid films were significantly improved. This is of interest when considering applications such as wound dressing, where flexibility and tensile strength are crucial [PERSON] et al. (2018); or in the regeneration of tissue such as cartilage and/or bone, where the mechanics of the environment plays a key role in the regeneration of the tissue [PERSON] et al. (2018); [PERSON] et al. (2018). [PERSON] and [PERSON] [PERSON] and [PERSON] (2018) explored the use of AgNPs loaded on a polydimethylsiloxane (PDMS) films and their resultant antibacterial activity and human cell compatibility with the aim of developing effective antibacterial coatings to address the global problem of surface microbial contamination above all in secondary care settings. Synthesized AgNPs were drop-coated onto a silicon wafer before being embedded in PDMS to form a uniformly coated matrix. In the short term, the AgNW-coated PDMS films demonstrated very high rates of killing against _E. coli_ and _S. aureus_ compared to a PDMS-only control. Furthermore, the number of bacterial cells (live and dead) adhered to the AgNW-containing films was significantly greater than the PDMS control. This fact led the authors to hypothesize that the hydrophobic moiety of the PVPmolecule, left on the AgNPs after synthesis, was able to establish a hydrophobic interaction with the bacterial cell wall. Therefore, a higher number of cells adhered to the wires with subsequent increase in bacterial cell death by contact with the film surface presenting a high concentration of released silver ions. [PERSON] and [PERSON] [41] also analyzed long-term antibacterial effects over a period of 30 days and bacterial mortality was found not to decrease over time. The authors surmised that this was due to an initial release of silver ions on day one and that the intercalated network of AgNPs allowed for a steady release of silver ions over a longer period, providing effective killing of both _E. coli_ and _S. aureus_ over 30 days.