A comparative study of NIH 3T3 fibroblast adhesion and proliferation on coatings of domestic and wild silk fibroin and their chitosan composites

Objective: To evaluate the in vitro cytotoxicity, adhesion, and proliferation of fibroblasts on film coatings made of Bombyx mori silk fibroin, wild silk (Tussah) fibroin, and their chitosan composites. Materials and methods. Four types of film coatings were investigated: Bombyx mori fibroin, wild silk fibroin, and their respective chitosan composites. The coatings were fabricated by casting aqueous polymer solutions followed by drying. Cytotoxicity was assessed in accordance with GOST R ISO 10993-5 using the extract assay method. NIH 3T3 fibroblast adhesion was evaluated 1 hour after seeding, while proliferation was assessed on days 1, 2, and 3 of culture. Cell quantification was performed following nuclear staining with 4′,6-diamidino-2-phenylindole (DAPI) using fluorescence microscopy combined with automated image analysis. Culture dishes containing sterile medium and medium supplemented with ethylenediaminetetraacetic acid or dimethyl sulfoxide served as control groups. Results. All tested coatings supported fibroblast viability, with metabolic activity levels comparable to those observed on standard culture plastic. Fibroblast adhesion and proliferation were consistently higher on wild silk fibroin coatings compared with Bombyx mori fibroin coatings at all time points. The incorporation of chitosan further enhanced both cell adhesion and proliferation. The most pronounced cellular response was observed on composite coatings based on wild silk fibroin and chitosan. Conclusion. Film coatings based on wild silk fibroin demonstrate an enhanced ability to support fibroblast adhesion and proliferation in vitro – more than twice as high as that of Bombyx mori fibroin with chitosan. Composite systems incorporating chitosan further enhance these properties, making them promising candidates for the development of functional biomedical coatings.

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