Silver Nanocluster Embedded Composite Nanoparticles for Targeted Prodrug Delivery in Cancer Theranostics.

Cancer therapy with theranostic nanoparticles having the dual properties of concurrent delivery of therapeutics and its tracking offers a huge prospect to overcome the limitations of conventional therapy. Delivery of the nontoxic prodrug, which converts into the toxic drug due to cellular stimuli, offers a great deal of scope in cancer therapy. The paracetamol dimer (PD) generally considered as nontoxic is encapsulated with fluorescent silver nanocluster (Ag NC) embedded composite nanoparticles where it acts as a prodrug. This is possibly converted to a toxic metabolite due to elevated reactive oxygen species (ROS), leading to apoptosis mediated cell death. Conjugation of folic acid with these composite NPs offers the credibility of distinguishing between two different cancer cell lines such as HeLa, which overexpresses folic acid receptors, and A549, which down-regulates its expression, probed by the fluorescence intensity of Ag NCs. Importantly, Ag NCs along with PD synergistically induce prodrug mediated targeted cell death at a much reduced concentration of silver. Thus, theranostic nanocarriers have been developed offering the dual property of therapy and imaging based on the differential uptake.