Silk fibroin microgels as a platform for cell microencapsulation

• Published in: Journal of materials science. Materials in medicine 2022-12, Vol.34 (1), p.3-12, Article 3
• Main Authors: Bono, Nina, Saroglia, Giulio, Marcuzzo, Stefania, Giagnorio, Eleonora, Lauria, Giuseppe, Rosini, Elena, De Nardo, Luigi, Athanassiou, Athanassia, Candiani, Gabriele, Perotto, Giovanni
• Format: Article
• Language: English
• Subjects: Biomaterials; Biomedical Engineering and Bioengineering; Biomedical materials; Cell culture; Cell Encapsulation; Cell viability; Ceramics; Chemistry and Materials Science; Composites; Encapsulation; Fibroins - chemistry; Glass; Hydrogels; Hydrogels - chemistry; Materials Science; Mechanical properties; Metabolites; Microencapsulation; Microgels; Molecular weight; Myoblasts; Natural Materials; Paracrine signalling; Polymer Sciences; Porosity; Regenerative Medicine/Tissue Engineering; Silk; Silk fibroin; Spectroscopy, Fourier Transform Infrared; Stiffness; Structural integrity; Surfaces and Interfaces; Thin Films; Tissue Engineering Constructs and Cell Substrates; Vascular endothelial growth factor
• ISSN: 1573-4838; 0957-4530; 1573-4838
• DOI: 10.1007/s10856-022-06706-y

Cell microencapsulation has been utilized for years as a means of cell shielding from the external environment while facilitating the transport of gases, general metabolites, and secretory bioactive molecules at once. In this light, hydrogels may support the structural integrity and functionality of encapsulated biologics whereas ensuring cell viability and function and releasing potential therapeutic factors once in situ. In this work, we describe a straightforward strategy to fabricate silk fibroin (SF) microgels (µgels) and encapsulate cells into them. SF µgels (size ≈ 200 µm) were obtained through ultrasonication-induced gelation of SF in a water-oil emulsion phase. A thorough physicochemical (SEM analysis, and FT-IR) and mechanical (microindentation tests) characterization of SF µgels were carried out to assess their nanostructure, porosity, and stiffness. SF µgels were used to encapsulate and culture L929 and primary myoblasts. Interestingly, SF µgels showed a selective release of relatively small proteins (e.g., VEGF, molecular weight, M W  = 40 kDa) by the encapsulated primary myoblasts, while bigger (macro)molecules (M W  = 160 kDa) were hampered to diffusing through the µgels. This article provided the groundwork to expand the use of SF hydrogels into a versatile platform for encapsulating relevant cells able to release paracrine factors potentially regulating tissue and/or organ functions, thus promoting their regeneration. Graphical Abstract