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Introduction: Albumin-nucleic acid biomolecular drug designs offer modular multifunctionalisation and extended circulatory half-life for improved efficacy and reduced side-effects. However, the clinical potential is currently limited by poor stability of conventional thiol conjugation and DNA nucleotides. This work aims to improve the stability of thiol conjugation and nucleic acid assembly by employing a fast-hydrolysing monobromomaleimide (MBM) linker and nuclease-resistant nucleotide analogues, respectively. Methods: The biomolecular assemblies were formed by site-selective conjugation of an oligonucleotide to cysteine 34 (Cys34) of albumin using the MBM linker, followed by annealing of a complementary oligonucleotide functionalised with either a fluorophore or the cytotoxic drug monomethyl auristatin E (MMAE). Formation of conjugates and assemblies were confirmed by gel shift analysis and mass spectrometry, followed by investigation of serum stability and cancer cell killing by gel electrophoresis and MTT viability assay, respectively.Results: The MBM linker was shown to rapidly conjugate to Cys34 of albumin and remain attached during a stabilising hydrolysis step. Albumin-nucleic acid assemblies employing stabilised nucleotide analogues afforded very high serum stability as exhibited by retained integrity of these assemblies after 72 hrs of incubation in 50% serum at 37°C, in contrast to conventional DNA assemblies that are completely degraded after 24 hrs. The biomolecular assemblies showed retained neonatal Fc receptor (FcRn) engagement and FcRn-mediated cellular recycling that acts as a good predictor of in vivo circulatory half-life. The MMAE-functionalised assembly exhibited cytotoxicity in a human pancreatic cancer cell line with an IC50 of 342 nM, triggered by drug release from breakdown of an acid-labile linker.Conclusion: This work presents albumin-nucleic acid module-based assemblies with improved stability and retained module functionality, promoting the drug delivery potential of this biomolecular platform.