The combination of nanocellulose and the attachment of macromolecular drugs by boronic ester formation represents a promising platform to deliver ruthenium. The system displays improved drug loading efficiency compared to already-reported polymeric micelles. As the designed carrier system is aimed for its use in metastasis cancer treatment, the presence of boronic ester linkage between drug and carrier gives rise to the pH-responsive release of therapeutics. Our formulation offers the opportunity to modify the biocompatible drug carrier nanocellulose with various bioactive polymers quickly and efficiently while allowing release in an acidic tumour environment.