Various novel strategies for functionalization of gold and silver nanoparticles to hinder drug-resistant bacteria and cancer cells

A higher reactivity of nanomaterials specifically inorganic nanoparticles (NPs) compared to their counterparts, is caused by their unique physicochemical properties in the nanoscale such as large surface area to volume ratio and aspect ratio. In the case of metal and metal oxide nanoparticles (NPs), gold (Au) and silver (Ag) NPs have been known to have appropriate therapeutic activities particularly anticancer and antimicrobial effects against a wide range of multidrug-resistant bacteria and cancer cells. However, low biocompatibility, bioavailability, and biodegradability in antibacterial and anticancer doses of these NPs are main hindrances to obtain an efficient safe formulation. For optimizing the micro and nano formulations, functionalization of the surface of Ag and Au NPs by biocompatible organic or inorganic materials has been applied in recent investigations. Therefore, in this review, various novel strategies to functionalize Au and Ag NPs particularly to hinder drug-resistant cancer cells and bacteria, have been discussed. In the term of an effective anticancer formulation, side effects of chemotherapeutic agents may be attenuated via employing multifunctional micro and nano agents composed of anticancer drugs, biocompatible materials and Au or Ag NPs.