RAPTA‐Decorated Polyacrylamide Nanoparticles: Exploring their Synthesis, Physical Properties and Effect on Cell Viability

In this study, we report the first successful immobilisation of a known cytoactive [Ru(η6‐arene)(C2O4)PTA] (RAPTA) complex to a biologically inert polyacrylamide nanoparticle support. The nanoparticles have been characterised by zetasizer analysis, UV/Vis, ATR‐FTIR, TGA and ICP‐MS to qualitatively and quantitatively confirm the presence of the metallodrug on the surface of the carrier. The native RAPTA complex required a concentration of 50 μM to produce a cell viability of 47.1±2.1 % when incubated with human Caucasian colorectal adenocarcinoma cells for 72 h. Under similar conditions a cell viability of 45.1±1.9 % was obtained with 0.5 μM of RAPTA complex in its immobilised form. Therefore, conjugation of the RAPTA metallodrug to our nanoparticle carriers resulted in a significant 100‐fold decrease in effective concentration of ruthenium required for a near identical biological effect on cell viability. Nanomedicine: We present a novel nanomedicine consisting of a RAPTA metal‐based drug immobilised onto the surface of polyacrylamide nanoparticles. Our conjugates have been well characterised, and their effects on cell viability evaluated through in vitro MTT cytotoxicity assays against HT‐29 colorectal adenocarcinomas. Our conjugate offers a significant 100‐fold increase in performance compared to the RAPTA compound alone.