Evidence map›Paper›PMID 39994022›Full record

ArticleACS applied materials & interfaces2025

Indenting at the Microscale: Guidelines for Robust Mechanical Characterization of Alginate Microgels.

Philipp Harder, Leonard Funke, Jana Tamara Reh, Oliver Lieleg, Berna Özkale

Abstract read
In one paragraph

Article in ACS applied materials & interfaces, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Philipp HarderMicrorobotic Bioengineering Lab (MRBL), School of Computation Information and Technology, Technical University of Munich, Hans-Piloty-Straße 1, 85748 Garching, Germany.ORCID 0009-0003-5168-1301
Leonard FunkeMicrorobotic Bioengineering Lab (MRBL), School of Computation Information and Technology, Technical University of Munich, Hans-Piloty-Straße 1, 85748 Garching, Germany.ORCID 0009-0003-4823-0059
Jana Tamara RehMunich Institute of Biomedical Engineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany.ORCID 0009-0005-1462-8311
Oliver LielegMunich Institute of Biomedical Engineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany.ORCID 0000-0002-6874-7456
Berna ÖzkaleMicrorobotic Bioengineering Lab (MRBL), School of Computation Information and Technology, Technical University of Munich, Hans-Piloty-Straße 1, 85748 Garching, Germany.ORCID 0000-0002-3016-9363

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Microgels offer broad applications in bioengineering due to their customizable properties, supporting innovations in mechanobiology, tissue engineering, drug delivery, and cell therapy. This study focuses on characterizing ionically cross-linked alginate microgels using a nanoindentation technique, enabling precise assessment of their mechanical properties at the microscale. We report on the microfluidic fabrication of alginate microgels with varying sizes at different cross-linker concentrations and on the mechanical characterization of the resulting microgels in terms of Young's moduli as well as viscoelastic behavior. Measurements conducted using dynamic nanoindentation reveal that microgel elasticity is strongly influenced by the ionic composition of the surrounding media, in particular, the concentration of calcium and sodium. We demonstrate that the highest Young's modulus observed for ionically cross-linked alginate microgels is in deionized water (7.2 ± 0.9 kPa). A drastic softening effect is observed when the calcium cross-linked microgels are placed into a storage buffer containing divalent ions (0.7 ± 0.1 kPa) and cell culture media consisting of Dulbecco's Modified Eagle Medium (0.2 ± 0.1 kPa) with fetal bovine serum (0.4 ± 0.1 kPa). High concentrations of sodium were found to disrupt ionic cross-links, decreasing stiffness and increasing viscosity, with reversible effects observed upon switching back to deionized water. These findings highlight the importance of media selection for applications requiring mechanical stability, and we provide guidelines for measuring the mechanical properties of microgels in a robust manner that is applicable to a wide range of different conditions.

Indexed as

AlginatesMicrogelsCalciumElastic ModulusViscosityAlginatesCalciumMicrogelsalginateionic cross-linkingmicrogelsnanoindentationYoung’s modulus

Identifiers

PMID39994022
PMCPMC11891838

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.