**5. Biomedical application of silver nanoparticles**

Silver nanoparticles have diverted the attention of the scientific community and industrialist itself due to their wide range of applications in industry for the preparation of consumer products and highly accepted application in biomedical fields. Silver has function in antimicrobial, catalytic and biological systems and the unique physical and chemical properties of silver nanoparticles only increase the efficacy of silver. Though there are many mechanisms ascribed to the antimicrobial activity shown by silver nanoparticles, the actual and most reliable mechanism is not fully understood or cannot be generalized as the nanoparticles are found to act on different organisms in different ways.

During the past few years, silver nanoparticles became one of the most examined and explored nanotechnology-derived nanostructures, given the fact that silver nanoparticles proved to have interesting, challenging, and promising characteristics suitable for various biomedical applications [25]. Even though there is limited information regarding the toxicity and in vivo biological behavior, these nanostructures were used for a long time as antibacterial agents in the health industry cosmetics, food storage, textile coatings and some environmental applications [26].

The exclusiveproperty of silver nanoparticles areparticularly advantageous for cancer therapeutics since they led to an improved chemotherapeutic efficiency together with minimal systemic toxicity [27]. AgNPs attracted special attention for this particular domain, and were successfully evaluated as effective anti-tumor drug-delivery systems [28], acting either as passive [29] or active [30] nanocarriers for anticancer drugs. Recent studies evidenced the potential use of AgNPs as vaccine and drug carriers for specific and selective cell or tissue targeting [31]. In addition tothe great optical properties of AgNPs [32–34] the recent improvements in AgNP biocompatibility and stability viasurface modification strongly recommend nanostructured systems based on silver as specific, selective,and versatile candidates for drug-delivery applications [35].
