Primary surface measurement reported
Water contact angle (hydrogel wettability) was measured on GelMA and GelTA hydrogels prepared with and without EV incorporation.
Client Citation Analysis
Combinational regenerative inductive effect of bio-adhesive hybrid hydrogels conjugated with hiPSC-derived myofibers and its derived EVs for volumetric muscle regeneration
This study develops bio-adhesive hybrid hydrogels for volumetric muscle regeneration and uses water contact angle to characterize hydrogel surface wettability.
At-a-Glance Summary
Dropometer attribution in the paper
The Dropometer is cited as a “Droplet Lab Tensiometer (Droplet Lab, Ontario, Canada)” used to inject 16 μl water droplets for contact angle measurement, with contact angles after 1 s analyzed by ImageJ software.
How the surface-tension / contact-angle data were used in the study
Contact angle was used to describe hydrogel hydrophilicity and to compare wettability between GelTA and GelTA‑EVs hydrogels. The text also references contact angle comparisons for GelMA and GelMA‑EVs in supplementary figures.
Replication / reliability statement
Contact angle in Fig. 5M was quantified by ImageJ (n = 3).
Paper Details
Title
Combinational regenerative inductive effect of bio-adhesive hybrid hydrogels conjugated with hiPSC-derived myofibers and its derived EVs for volumetric muscle regeneration
Authors
Jiseong Kim; Myung Chul Lee; Jieun Jeon; et al.; Indranil Sinha; Su Ryon Shin
Journal
Bioactive Materials
Year
2025
Volume
43
Pages / Article
579–602
License
CC BY-NC-ND 4.0
36.2
Scopus metrics (Elsevier / Scopus rating 2024)
Scopus metrics (Elsevier / Scopus rating 2024)
CiteScore subject ranks (CiteScore 2024)
- Q1 - Materials Science, Biomaterials (3/140)
- Q1 - Engineering, Biomedical Engineering (5/323)
- Q1 - Biochemistry, Genetics and Molecular Biology, Biotechnology (4/314)
2.833
Scopus metrics (Elsevier / Scopus rating 2024)
4.075
Scopus metrics (Elsevier / Scopus rating 2024)
20.3
Journal Impact Factor (Clarivate JCR)
Journal Impact Factor (Clarivate JCR)
- Q1 - Materials Science, Biomaterials (2/55)
- Q1 - Engineering, Biomedical (3/124)
What Was Measured
Primary surface / interfacial measurement
Water contact angle was measured after 1 s following deposition of a 16 μl water droplet on the hydrogel surface to characterize wettability.
Supporting measurements
Hydrogel microstructure and surface/topography context was reported using scanning electron microscopy (SEM) and atomic force microscopy (AFM) outputs presented alongside contact angle within the hydrogel characterization set.
Water contact angle (droplet deposition)
Droplet Lab Tensiometer (Droplet Lab, Ontario, Canada)
Contact angle analysis
ImageJ software
Hydrogel SEM imaging
Hitachi S-4800 (Hitachi, Japan) scanning electron microscope (SEM)
Hydrogel surface topography / roughness / DMT moduli
AFM (ScanAsyst-Fluid + sharp-tipped cantilevers; DMT moduli evaluated computationally)
Role of the Dropometer
In the contact angle assay, hydrogels (GelMA or GelTA, prepared with or without EVs) were formed on glass using a 500 μm high and 10 mm diameter PDMS mold, swelled in DPBS for 3 h, and then dried with Kimwipes. A constant-volume water droplet (16 μl) was injected onto the gel surface using a Droplet Lab Tensiometer (Droplet Lab, Ontario, Canada), and the contact angle after 1 s was analyzed using ImageJ software.
These contact angle measurements were used to compare hydrogel wettability across formulations (including GelTA vs GelTA‑EVs) as part of the study’s hydrogel surface characterization.
Bring This Measurement Into Your Lab
If you need water contact angle on soft hydrogels or biomaterial scaffolds, we can show you a fixed volume sessile drop workflow on your samples.
Key Findings
Hydrophilic wettability range reported for GelTA-based hydrogels
GelTA and GelTA‑EVs hydrogels are described as having good hydrophilicity, with a contact angle around 50–70°, which the authors link to maximizing cell adhesion.
GelTA and GelTA‑EVs showed similar contact angle
In Fig. 5M, GelTA and GelTA‑EVs hydrogels displayed similar contact angle, quantified by ImageJ (n = 3).
GelMA and GelMA‑EVs contact angle comparison was referenced in supplementary figures
The text describes GelMA‑EVs as showing similar contact angle compared with pristine GelMA hydrogel and points to Figs. S6K and S6L.
Figures & Visuals
What it shows
Shows GelTA and GelTA‑EVs hydrogels with similar contact angle, quantified by ImageJ (n = 3).
What it shows
Referenced in the text for contact angle comparison between GelMA‑EVs and pristine GelMA hydrogels.
Why It Matters
Within the hydrogel characterization workflow in this study, the contact angle assay provides a direct wettability readout used to describe surface hydrophilicity and to compare formulations with and without EV incorporation. The authors explicitly connect the reported contact angle range to cell adhesion considerations while presenting contact angle as part of the broader surface/structure characterization set for these biomaterial scaffolds.
Expert Perspective
Practical Takeaways
Use fixed droplet volume and a defined timepoint
The assay uses 16 μl water droplets and evaluates contact angle after 1 s, with angle analysis performed in ImageJ.
Standardize hydrogel pre-conditioning before wetting tests
Hydrogels are swelled in DPBS for 3 h and then dried carefully with Kimwipes prior to droplet deposition.
Document casting and mounting geometry for surface measurements
Hydrogels are formed using a 500 μm high and 10 mm diameter PDMS mold and fixed on glass by placing a glass slide on top during preparation.
Use contact angle to compare EV-loaded vs pristine hydrogels
The study reports contact angle comparisons for GelTA vs GelTA‑EVs (Fig. 5M) and references GelMA vs GelMA‑EVs comparisons in supplementary figures.
Report replication when presenting contact angle comparisons
The contact angle result in Fig. 5M is reported with n = 3.
Frequently Asked Questions
What did the Droplet Lab instrument measure in this study?
The authors used a Droplet Lab Tensiometer to place 16 μl water droplets on GelMA and GelTA hydrogels prepared with and without extracellular vesicles (EVs). The contact angle 1 s after deposition was analysed in ImageJ software, after the hydrogels had been swelled in DPBS for 3 h and dried carefully with Kimwipes (Section 4.24).
What contact angles did the authors report, and what do they mean?
The authors report that GelTA and GelTA-EVs hydrogels showed good hydrophilicity, with water contact angles of around 50 to 70° and no significant difference with or without EVs (Fig. 5M, n = 3). They link this range to conditions that can maximize cell adhesion, and report a similar contact angle for GelMA-EVs and pristine GelMA hydrogels in the supplementary figures.
What was outside the scope of the contact angle measurements?
Each value is a static angle read 1 s after the droplet was placed, so advancing and receding angles, contact angle hysteresis and longer time courses were not part of this work. Surface roughness and stiffness were characterized separately by AFM, and pore structure by SEM.