• New classes of materials allow for diversity (e.g. iron oxide instead of gadolinium)
  • New imaging modalities (e.g. fluorescence) possible
  • Multimodal imaging
  • Theranostics
  • Control over tissue distribution (i.e. targeting)
  • Longer circulation time and control over pharmacokinetics through design parameters
  • Poorly understood interactions between nanomaterials and biological systems
  • Challenges in scale-up to consistent large-scale manufacturing
  • Concerns regarding materials stability during storage (e.g. aggregation, degradation)
  • Potential issues with bio-accumulation due to inability to metabolize and excrete large particles
  • Potential for toxic breakdown products (e.g. Cd from CdSe quantum dots); study of nano-toxicology is quite complex
  • Regulatory barriers
Table 2: Overview of main advantages and disadvantages of nanotechnology-based contrast agents.