Do you need appropriate MNP-free control matrix for each type of human tissue that is the focus of the study (e.g., brain, blood, muscle, liver, etc.)?

Answer Explanations

• Yes (please explain)

  Expert 9
  Ideally yes. However, in many instances, this will not be practically viable and some extrapolation between tissues will have to be made.
• Yes (please explain)

  Expert 3
  Different tissues may affect the different protocols used (e.g., digestion) and, therefore, an equivalent matrix should be used. 
• Yes (please explain)

  Expert 2
  Yes, there is a need for an appropriate MNP-free control matrix for each type of human tissue analyzed when working with magnetic nanoparticles. This is important due to the fact that different tissues like liver, brain, blood, and muscle, possess distinct biochemical features that could significantly impact the behavior and detection of MNPs, therefore influencing  the signal response, the recovery efficiency, and  also the background interference. 
• Yes (please explain)

  Expert 4
  In some cases, a MNP-free control matrix is not needed and it then is possible to use other tissue. In other cases, like the brain, there is the issue that the matrix is not homogeneous in the sens that MNP do not distribute evenly within the matrix. It such cases it is even needed to know what part of the organ is available.
• Yes (please explain)

  Expert 6
  Currently, several studies showed finding MNPs in human brain, blood, and other organs, particularly PE-like hydrocarbon-based particles. However, human tissue is rich of lipids including fatty acids, which are also hydrocarbon-based materials. False positive identification is now drawing researcher's attention and effort to minimize/mitigate the metrics/background effort. Appropriate MNP-free control matrix will not help researchers to improve methodology on actual limit of quantitation but also can tell whether applied method has false positive potential. 
• Yes (please explain)

  Expert 8
  Each tissue type has different proportions of lipids, carbohydrates, and protein.  These components will digest differently and each can interfere with analysis.
• Yes (please explain)

  Expert 7
  Each tissue has a unique biochemical composition and may have different matrix effects, recovery rates, limits of detection and quantification and reproducibility.
• Yes (please explain)

  Expert 1
  Each type of sample matrix is different in terms of composition and therefore sample preparation and analysis follow different protocols.  The interferences, including matrix effects, contributed from these matrices can be different.  Therefore MNP-free control matrix for each tissue type is recommended.  However, this may not be feasible in every case and at least one surrogate matrix should be used for matrix spike and matrix blank samples.