# Comparative analysis of electron microscopy techniques for hydrogel microarchitecture characterization: SEM, CryoSEM, ESEM, and TEM

Jeanne Aigoin, Bruno Payre, Jeanne Minvielle Moncla, Mélanie Escudero, Dominique Goudounèche, Daniel Ferri-Angulo, Pierre-François Calmon, Laurence Vaysse, Philippe Kémoun, Laurent Malaquin, et al.

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## ► To cite this version:

Jeanne Aigoin, Bruno Payre, Jeanne Minvielle Moncla, Mélanie Escudero, Dominique Goudounèche, et al. Comparative analysis of electron microscopy techniques for hydrogel microarchitecture characterization: SEM, CryoSEM, ESEM, and TEM. Journées du RIME, May 2024, Bordeaux, France. hal-05268482

HAL Id: hal-05268482

https://hal.science/hal-05268482v1

Submitted on 19 Sep 2025

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## Characterization of hydrogels' microarchitecture

### Hydrogels

* Polymeric network

* Tridimensionnal

* Can hold 90% of its structure as water

* Synthetic or natural

* Can be physically or chemically bonded

### Materials

* Gelatin methacrylate (GelMA)

* Hyaluronic acid methacrylate (HAMA)

Hydrogels : porous structure

Photosensitive materials

Cross-linking under UV light at 405 nm

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From a hydrogel in solution to a solid hydrogel

### Main purposes:

* Preserve the microarchitecture of hydrogels

* Finding a technique enabling us to observe the hydrogels' structure to understand more their behaviour/properties

## Different technics employed

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Observations of GelMA (10% w/v) and HAMA (3% w/v)

## Pores dimension and cells observations

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* Time of UV exposure is impacting the microarchitecture

* Alterations induced by freeze drying

* Charging effect with SEM that damages the sample

* CryoSEM displays good resolution but limited in magnification

* Exceptional resolution and polymer network organization with TEM : nanoporous structures

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* Adipose-derived stem cells (ASCs) within a mixture of GelMA 12% (C and D) and 10% (E and F)

* TEM allows for deep penetration into samples, thereby revealing the internal details of cells encapsulated within hydrogels

* Observation of cellular structures at a nanoscale level

* Remodeling of the hydrogel by the cells

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GelMA 10% (C and D) and 12% (E and F) encapsulated with Adipose-derived stem cells