Porous Lactose-Modified Chitosan Scaffold for Liver Tissue Engineering: Influence of Galactose Moieties on Cell Attachment and Mechanical Stability

Birong Wang,Min Li,Qinggang Hu,Shaobo Hu,Fengxiao Yang,Le Cui,Bo Gong,Qi Chang Zheng,Tao Wan

doi:10.1155/2016/2862738

Abstract

Galactosylated chitosan (CTS) has been widely applied in liver tissue engineering as scaffold. However, the influence of degree of substitution (DS) of galactose moieties on cell attachment and mechanical stability is not clear. In this study, we synthesized the lactose-modified chitosan (Lact-CTS) with various DS of galactose moieties by Schiff base reaction and reducing action of NaBH4, characterized by FTIR. The DS of Lact-CTS-1, Lact-CTS-2, and Lact-CTS-3 was 19.66%, 48.62%, and 66.21% through the method of potentiometric titration. The cell attachment of hepatocytes on the CTS and Lact-CTS films was enhanced accompanied with the increase of galactose moieties on CTS chain because of the galactose ligand-receptor recognition; however, the mechanical stability of Lact-CTS-3 was reduced contributing to the extravagant hydrophilicity, which was proved using the sessile drop method. Then, the three-dimensional Lact-CTS scaffolds were fabricated by freezing-drying technique. The SEM images revealed the homogeneous pore bearing the favorable connectivity and the pore sizes of scaffolds with majority of 100 μm; however, the extract solution of Lact-CTS-3 scaffold significantly damaged red blood cells by hemolysis assay, indicating that exorbitant DS of Lact-CTS-3 decreased the mechanical stability and increased the toxicity. To sum up, the Lact-CTS-2 with 48.62% of galactose moieties could facilitate the cell attachment and possess great biocompatibility and mechanical stability, indicating that Lact-CTS-2 was a promising material for liver tissue engineering.

Highlights

Serving as an interdisciplinary field in biomedical engineering, liver tissue engineering aims to regenerate new living tissue for replacing diseased or damaged tissues/organs in recent years [1]
The glucose groups of lactose exhibit both hemiacetal hydroxyl of ring structure and carbonyl of chain structure illustrated in Figure 1, whereas galactose groups keep stable ring structure
Through the Schiff base reaction and the reducing action of NaBH4, the chemical bond was formed between the carbonyl groups on lactose and the primary amines on CTS

Summary

Introduction

Serving as an interdisciplinary field in biomedical engineering, liver tissue engineering aims to regenerate new living tissue for replacing diseased or damaged tissues/organs in recent years [1]. The three-dimensional scaffold, as one of the three essential factors of tissue engineering, is playing an extremely important role as adhesive substrate and in connective tissue framework and payload and storage of growth factors [2, 3]. Development of new class artificial scaffold is an imperative task to guide cell attachment, survival, cell morphological changes, proliferation, and differentiation for liver tissue engineering. The constituents of extracellular matrix (ECM) materials are one of the most important key factors to determine the properties of tissue scaffold. As a natural biomaterial with its essential advantage in biodegradation, biocompatibility, and nonimmunoreaction, chitosan (CTS) is an ideal ECM material for three-dimensional scaffold [4,5,6]. The CTS and its derivatives are widely applied in tissue engineering

Methods

Results

Conclusion