Injectable Cryopreservable Alginate-Gelatin Microbeads for Pro-Angiogenic Cell Therapy

Touani Kameni F, Badr S, et al.

ACS Biomaterials Science & Engineering

École de Technologie Supérieure (ÉTS), Centre de Recherche du CHUM, Université de Montréal

RESEARCH SUMMARY

This study developed an oil-free, air-assisted coaxial encapsulation process to produce injectable alginate–gelatin microbeads (~400–500 µm diameter) loaded with human mesenchymal stromal cells (MSCs) as a clinically transferable pro-angiogenic cell therapy product for ischemic tissue repair. Alginate-only (ALG) and alginate–gelatin formulations (ALG-Gel3%, ALG-Gel5%) were compared for size distribution, injectability through 21G/23G needles, mechanical properties, stability, MSC viability, VEGF release, and pro-angiogenic paracrine activity in HUVEC scratch-wound assays. Adding gelatin improved MSC survival and tended to enhance pro-angiogenic function, with ALG-Gel3% identified as the best-performing formulation (minimal loss in mechanics versus ALG, stable in HBSS for 14 days). Cryopreservation (trehalose + DMSO) reduced compressive strength/strain-at-failure, MSC survival, and VEGF release, but post-thaw viability remained >80% after 7 days and microbead-conditioned coculture still promoted robust endothelial migration/proliferation.

Microbead mechanics were quantified using a CellScale MicroSquisher in Hank’s balanced salt solution (HBSS) at room temperature. Individual microbeads were compressed with a 2 × 2 mm microplate attached to a 406 µm diameter microbeam. For each bead, three compression cycles to 30% strain were applied over 60 s, followed by a 10 s hold phase and a 60 s recovery phase. Young’s modulus was calculated at 20% strain using a Hertzian half-space contact model. Separately, beads were compressed to 80% strain over 60 s to determine maximum compressive strength and strain at rupture. Mechanical stability was assessed by incubating beads in HBSS at 37 °C for 14 days and periodically re-measuring modulus and diameter.

AUTHORS

Touani Kameni, F., Badr, S., Vigouroux, Y., Madadian, E., Ahmadi, A., Lerouge, S..

PUBLICATION DETAILS

JOURNAL

ACS Biomaterials Science & Engineering

YEAR

2025

INSTITUTIONS

École de Technologie Supérieure (ÉTS), Centre de Recherche du CHUM, Université de Montréal

COUNTRIES

Canada

INSTRUMENT USED

MicroSquisher

TESTING METHODS

Compression TestingHydrated and Temperature Controlled TestingMicro-Mechanical TestingViscoelastic & Time-Dependent Testing

RESEARCH APPLICATIONS

Cell Laden HydrogelsDrug Screening & Drug Delivery MechanicsInjectable & Regenerative Biomaterials

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