4d multimodal nanomedicines made of nonequilibrium au-fe alloy nanoparticles

Vincenzo Amendola, Veronica Torresan, Daniel Forrer, Andrea Guadagnini, Denis Badocco, Paolo Pastore, Maurizio Casarin, Annabella Selloni, Diego Coral, Marcelo Ceolin, Marcela B. Fernandez Van Raap, Alice Busato, Pasquina Marzola, Antonello E. Spinelli

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


Several examples of nanosized therapeutic and imaging agents have been proposed to date, yet for most of them there is a low chance of clinical translation due to longterm in vivo retention and toxicity risks. The realization of nanoagents that can be removed from the body after use remains thus a great challenge. Here, we demonstrate that nonequilibrium gold-iron alloys behave as shape-morphing nanocrystals with the properties of self-degradable multifunctional nanomedicines. DFT calculations combined with mixing enthalpy-weighted alloying simulations predict that Au-Fe solid solutions can exhibit self-degradation in an aqueous environment if the Fe content exceeds a threshold that depends upon element topology in the nanocrystals. Exploiting a laserassisted synthesis route, we experimentally confirm that nonequilibrium Au-Fe nanoalloys have a 4D behavior, that is, the ability to change shape, size, and structure over time, becoming ultrasmall Au-rich nanocrystals. In vivo tests show the potential of these transformable Au-Fe nanoalloys as efficient multimodal contrast agents for magnetic resonance imaging and computed X-ray absorption tomography and further demonstrate their self-degradation over time, with a significant reduction of long-term accumulation in the body, when compared to benchmark gold or iron oxide contrast agents. Hence, Au-Fe alloy nanoparticles exhibiting 4D behavior can respond to the need for safe and degradable inorganic multifunctional nanomedicines required in clinical translation.

Original languageEnglish (US)
Pages (from-to)12840-12853
Number of pages14
JournalACS Nano
Issue number10
StatePublished - Oct 27 2020

All Science Journal Classification (ASJC) codes

  • General Engineering
  • General Materials Science
  • General Physics and Astronomy


  • Alloys
  • Au nanoparticles
  • CT
  • Degradable materials
  • Fe nanoparticles
  • MRI
  • Nanomedicine


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