The Effect of Collagen on Porous Structure of Chitosan-collagen Sponges

Chitosan-collagen sponges are biodegradable and osteoconductive. Objective: This study aimed to determine of the effect of collagen on the porous structure and growth of cells on composite sponges. Methods: The sponges were divided into 4 groups: Chitosan; Collagen; 1:1 ratio of chitosan-collagen and 1:2 ratio of chitosan-collagen. They were prepared by cross-linking the composite suspensions with 0.05% glutaraldehyde then underwent a freeze-drying procedure. Mouse osteoblast cell line, MC3T3-E1 was seeded on 8x3mm scaffolds. The constructs were cultivated in a culture medium for 72 hours. The porous structure of sponges was then studied in cross-sectional and longitudinal directions using scanning electron microscope and the pore sizes were measured using Image-Pro^® Plus image analysis software. Fluorescein diacetate and propidium vital stains were performed to detect growth and attachment of cells on scaffolds using a confocal laser scanning microscope. Results: The composite sponges of 1:1 and 1:2 ratio of chitosan-collagen demonstrated greater homogenous pore size and shape than collagen and chitosan sponges, respectively. In the cross-section, the collagen sponges showed the largest pore size (84.77±12.9µM, 51.67-115.02µM), followed by 1:2 chitosan-collagen sponges (80.63±11.8µM, 53.57-113.41µM), which were significantly larger than 1:1 chitosan-collagen (66.69±9.92µM, 50.11-94.43µM) and chitosan sponges (64.33±10.09µM, 35.09-88.10µM) (p<0.05). Vital stains illustrated strong vitality and growth of cells within the porous structure of sponges. Distribution of cells on collagen and 1:2 and 1:1 chitosan-collagen sponges were more homogenous than chitosan sponges. Conclusions: Collagen improved the porous structure of chitosan-collagen sponges. The 1:2 ratio chitosan-collagen sponges' pore sizes were large enough to support attachment and the growth of osteoblasts in vitro. The study was supported by Prince of Songkla Research Fund.