Results

Advanced Characterisation (WP2)

Improving the characterisation of complex nanomedicines

WP2 compared physical and chemical characterisation methods for metal oxide nanoparticles, complex surface coatings, liposomes and RNA lipid nanoparticles. Its results have been consolidated into practical guidance, decision tables, SOPs, case studies, publications and learning resources.

One key lesson

No single method can fully characterise a complex nanotherapeutic. The right approach depends on your material, your measurand and the question you need to answer.

3decision tables

9standard operating procedures

3peer-reviewed articles

1Academy replay

Our results

Explore the outputs and resources developed by WP2

Flagship result

Characterising a complex MRI contrast agent

WP2 selected the commercially available preclinical MRI contrast agent FeraSpin™ R as a case-study material. The formulation contains carboxy-dextran-coated iron oxide nanoparticles and presents a broad particle-size distribution, including small cores and larger particle assemblies. Because some agglomeration may be induced by sample preparation, the study carefully distinguishes what each technique and sampling scale can establish.

Partners combined SAXS, MD AF4, microscopy, thermal analysis and spectroscopic techniques to investigate particle size, subpopulations, chemical homogeneity and surface coating properties. The comparison showed the value and the limitations of combining results obtained at different length scales and sampling volumes.

Journal: Nanoscale AdvancesReference: 2026, 8, 3136–3150DOI: 10.1039/D5NA00463BAccess: Open access — CC BY 3.0

View all METRINO publications

Resources

Resources developed for the nanomedicine community

WP2 delivered two complementary documents for the nanomedicine community: a good practice guide including decision tables and SOPs, and a tutorial article presenting an analytical strategy for liposomes and RNA LNPs.

How can this resource help you?

Use the guide to support method selection and reporting for the physical and chemical characterisation of nanotherapeutics.

It contains three decision tables and nine SOPs developed through work on UCNPs, IONPs, HfO₂ nanoparticles and FeraSpin-like systems.

Version: 1Published: 13 July 2026DOI: 10.5281/zenodo.21641655Licence: CC BY 4.0

Not sure which method to use?
Use three decision tables to compare methods for particle size, particle concentration and chemical characterisation, including their main limitations.
Looking for a documented procedure for size or concentration?
Use five SOPs covering particle size determination by SAXS, particle number concentration determination by SAXS, hybrid AFM and SEM dimensional measurements, particle size distribution by MD AF4, and particle size determination by backscattering DLS.
Open the SAXS calculation notebook(opens in a new tab)
Need to characterise surface properties?
Use four SOPs covering TGA, ATR FTIR, XPS and qNMR for coating amount, chemical composition and surface ligand characterisation.

Access D3 on Zenodo

Published tutorial article

Liposomes and lipid nanoparticles: a tutorial for advanced chemical and structural characterisation

The article presents a coordinated analytical strategy for dimensions, internal structure, surface chemistry, lipid composition and RNA payload, showing why complementary methods are needed to investigate complex lipid-based nanotherapeutics.

Published: 15 May 2026Journal: European Journal of Pharmaceutical Sciences, 222, 107556DOI: 10.1016/j.ejps.2026.107556Licence: CC BY-NC 4.0

What will you find in the article?

How complementary methods can be combined to investigate particle dimensions, morphology and internal structure.
Approaches for examining lipid composition and molecular organisation.
Methods for assessing surface chemistry and particle composition.
Strategies for evaluating RNA loading, encapsulation efficiency and payload integrity.
Practical considerations and limitations affecting the interpretation of results across different techniques.

Read the tutorial article Open supporting dataset

Comparing complementary surface-analysis methods

Cross-validation of analytical methods for citrate ligand quantification on upconversion and iron oxide nanoparticles

The study compares RP-HPLC, TGA and PyGC-MS for citrate quantification on UCNPs and IONPs. It demonstrates the value of multimethod cross-validation while identifying material- and method-specific effects that can influence interpretation.

Published: 4 March 2026Journal: Analytical and Bioanalytical Chemistry, 418, 5181–5191DOI: 10.1007/s00216-026-06402-8Licence: CC BY 4.0

What does the comparison show?

RP-HPLC provided reproducible, citrate-selective measurements for dissolved UCNP and IONP samples.
TGA supplied complementary information on total organic content, but is not citrate-selective.
PyGC-MS reduced sample preparation and sample-mass requirements, while revealing material-specific limitations for IONPs.
Cross-validation helps identify method-dependent effects and strengthens confidence in nanoparticle surface analysis.

Read the citrate study

Learn from the experts

How to better characterise your nanomedicine

Four questions to ask yourself before your measurement

Good measurement starts before the instrument is selected. Use these four questions to move from the decision you need to support to a method and result you can interpret with confidence.

1
What question are you trying to answer?
Start with the scientific or practical decision that the measurement needs to support.
2
What exactly do you need to measure?
Define the measurand clearly, including the property, material and conditions of interest.
3
Which method fits the material and measurand?
Choose a method suited to the material and measurand, and combine complementary techniques when they provide distinct or independently corroborating information.
4
What affects interpretation and comparison?
Document sample preparation, calibration, data treatment, uncertainty, assumptions and method limitations.

See how experts apply this framework when choosing and combining methods in the MetrINo Academy replay.

MetrINo Academy

Choosing the Right Measurement Method: A Practical Approach

Presented by Dr Christian Gollwitzer, PTB, and Prof Yuri Antonio Diaz Fernandez, University of Pavia. Moderated by Dr Alexandre Ceccaldi, ETPN.

What you will learn in this webinar

Why different methods can yield different yet valid results.
How WP2’s decision tables support method selection for a specific material and measurand.
How uncertainty evaluation and complementary methods support meaningful comparison.

What WP2 taught us

From community needs to more meaningful and comparable characterisation

From characterisation challenges to practical lessons

WP2 started from recurring needs identified across the nanomedicine community and translated them into practical guidance for selecting, combining, interpreting and reporting physical and chemical characterisation methods.

Characterisation needA complete picture of a complex formulation
Size alone cannot describe morphology, internal structure, surface chemistry, composition, concentration and payload integrity.
WP2 responseCombine methods that answer distinct questions
Complementary techniques are useful when each contributes different, clearly defined information about the material.
Characterisation needComparable particle-size results
A core diameter, hydrodynamic diameter, projected diameter and radius of gyration are not directly equivalent.
WP2 responseDefine the measurand before comparing values
Results from different sizing methods may be complementary, but they should not be treated as interchangeable.
Characterisation needA method suited to the material
A technique appropriate for a monodisperse metal oxide nanoparticle may not suit an LNP, liposome or aggregated formulation.
WP2 responseMatch the technique to the material properties
Composition, polydispersity, morphology, surface coating and physical state determine which techniques can provide useful information.
Characterisation needResults that others can interpret
The reported value depends on the full process, not only on the instrument or analytical technique.
WP2 responseReport the conditions behind the value
Sample preparation, calibration, uncertainty, fitting assumptions and data-processing choices should accompany the result.

From results to community use

Practical routes to use, teach and build on the WP2 legacy

Three ways to use and build on the WP2 results

Use them.
Read and apply the decision tables, SOPs and analytical strategies when planning or reviewing measurements.
Teach them.
Use the Academy replay and practical questions to support students, colleagues and laboratory teams.
Build on them.
Reuse and adapt the resources when developing methods, training materials or future guidance, while keeping their stated scope and limitations visible.

Scientific contacts