WP4 developed and evaluated workflows to identify, localise and compare inorganic nanoparticles in tissue phantoms and biological tissue models. By connecting optical, elemental and chemical imaging methods, the work examined how complementary views of the same sample can be combined into stronger spatial evidence.
WP4 first compared complementary signals under controlled conditions, then examined what remained measurable in three-dimensional models, tissue sections and single-cell systems.
The strongest contribution is not one universal image or method. It is a practical evidence chain showing how sample complexity, signal mechanism, spatial resolution and method order shape what can be claimed.
Within the WP4 internal ILC, participating laboratories compared results generated with complementary imaging and mass-spectrometry methods on common UCNP-containing phantom samples. Related studies then explored how these approaches performed in 3D tumour models, HfO₂-containing tissue sections and A549 cell systems, while keeping the limits of each method explicit.
D7 consolidates protocols for biological sample preparation and nanoparticle measurements in cells and tissues. D8 documents the internal comparison of approaches for nanoparticle identification, localisation and quantification in tissue-phantom samples.
Correlative imaging starts with one question, not a collection of instruments. Four connected decisions determine whether different views can ultimately be compared.
Is the goal to detect, localise, quantify, identify chemistry or understand tissue context?
Choose controlled phantoms, 3D models, tissue sections or cells according to the evidence required.
Sequence methods so early measurements do not remove or alter information needed later.
Define landmarks, regions of interest, calibration, data formats and reporting before acquisition.
Academy 4 makes these decisions tangible by showing why one spot can generate several valid but different views — and why alignment remains one of the hardest practical steps.
Presented by Dr Leonardo Mortati, INRiM.
“Correlative imaging could be a powerful solution…”Dr Leonardo Mortati, INRiM — Academy 4
WP4 treated sample preparation, method order, registration and interpretation as one connected measurement problem. Its value lies both in the successful correlations and in the limitations observed.
Known-content systems provide a necessary baseline before signals are interpreted in tissues or cellular models.
Autofluorescence, surface roughness, background and sensitivity can change whether detection or quantification remains feasible.
Optical, elemental and chemical approaches contribute different measurands and spatial scales; complementarity is not numerical equivalence.
Documenting when a method supports detection, localisation or quantification is part of trustworthy metrology, not a result to hide.
Exploratory work with additional tissues and techniques revealed cases where matrix overlap, nonspecific fluorescence, insufficient sensitivity or resolution prevented robust quantitative interpretation. Those boundaries help future users choose methods more realistically.
WP4 leader, INRiM
Scientific contact for the WP4 work on tissue phantoms, correlative imaging, internal comparison and nanoparticle localisation in complex biological samples.
The grid reflects organisations documented as contributors to D7 and D8.
The METRINO project has received funding from the European Partnership on Metrology (Grant #22HLT04), co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or EURAMET. Neither the European Union nor the granting authority can be held responsible for them.
