Bioresponsive Polyoxometalate Cluster for Redox-Activated Photoacoustic Imaging-Guided Photothermal Cancer Therapy

Dalong Ni, Dawei Jiang, Hector F. Valdovinos, Emily B. Ehlerding, Bo Yu, Todd E. Barnhart, Peng Huang, Weibo Cai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

98 Scopus citations


Although various types of imaging agents have been developed for photoacoustic (PA) imaging, relatively few imaging agents exhibit high selectivity/sensitivity to the tumor microenvironment for on-demand PA imaging and therapy. Herein, molybdenum-based polyoxometalate (POM) clusters with the highest oxidation state of Mo(VI) (denoted as Ox-POM) were designed as novel agents for redox-activated PA imaging-guided photothermal therapy. Capable of escaping from recognition and capture by the liver and spleen, these renal clearable clusters with ultrasmall size (hydrodynamic size: 1.9 nm) can accumulate in the tumor, self-assemble into larger nanoclusters at low pH, and are reduced to NIR absorptive agents in the tumor microenvironment. Studies in 4T1 tumor-bearing mice indicated that these clusters could be employed for bioresponsive PA imaging-guided tumor ablation in vivo. Our finding is expected to establish a new physicochemical paradigm for the design of PA imaging agents based on clusters, bridging the conventional concepts of “molecule” and “nano” in the bioimaging field.

Original languageEnglish (US)
Pages (from-to)3282-3289
Number of pages8
JournalNano letters
Issue number5
StatePublished - May 10 2017


  • Redox-responsive probes
  • photoacoustic imaging
  • photothermal therapy
  • polyoxometalate cluster
  • theranostic agent

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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