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

Abstract

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.

Bio‐Orthogonal Conjugation of a Cationic Metalloporphyrin to BSA and HSA via “Click” Chemistry

“…Determination of the photodynamic activity of BSA ‐ 2 and HSA ‐ 2 was carried out via an in vitro phototoxicity and MTT assay against human Caucasian colorectal adenocarcinoma cells (HT‐29) (Figure 3). Previously, we have utilized this cancer cell line as a useful tool to evaluate the therapeutic effectiveness of novel dual‐therapeutics, [30] PET/PDT theranostics, [21] anti‐cancer metallodrugs, [35] and nanoparticles, [36,37] The mechanism of cellular uptake was not investigated as these serum proteins and their conjugates are known to be internalised by endocytosis [38] . The cells were incubated with various concentrations of BSA ‐ 2 and HSA ‐ 2 in serum‐free media for 4 h following removal of the media by centrifugation.…”

Antifouling polymers for nanomedicine and surfaces: recent advances

“…Our final example featuring the use of poly(acrylamide)s in nanomedicine comes from the 2021 work of Sandland et al describing a novel process whereby the cytoactive complex Ru II arene 1,3,5-triaza-7-phosphaadamantane (RAPTA), an anticancer metallodrug, was immobilized on amine-functionalized poly(acrylamide) NPs. 71 The synthesis of the ruthenium( ii ) complex and its subsequent conjugation to NH 2 -functionalized poly(acrylamide) are depicted in Schemes 12 and 13. In biological assays, these metallodrug-conjugated NPs demonstrated improved anticancer activity at concentrations that were 100 times lower than with the free unconjugated RAPTA metallodrug, thus highlighting their potential in future clinical applications.…”