Cell attachment to Zein surfaces

Nanostructured biomaterials have been recently investigated in various biomedical applications, such as tissue engineering and circulating cancer cell retrieval. Understanding the mechanism of cell-substrate interaction is pivotal for exploiting the potential of those materials. Adhesion of cells to substrate surfaces is often mediated by tissue transglutaminase (tTG) in its role as a crosslinking enzyme. Zein, a corn protein, has been recently studied as a biocompatible material in tissue engineering. It is a prolamin containing multiple poly-glutamine strands. Previous studies suggested that glutamine residues on zein structure are involved in NIH 3T3 cell adhesion. Considering that tTG mediates cell adhesion mainly through crosslinking between glutamine residues and lysine residues, we hypothesized that the possible function of zein glutamine residues to cell adhesion may be associated with tTG. To explore this hypothesis, a zein film was constructed with glutamine residues exposed to cells. Results confirmed that zein substrate enhanced cell spreading and adhesion. SDS-PAGE confirmed zein is a glutamine donor for tissue transglutaminase. Deposition of tTG on zein coating films further enhanced cell spreading and adhesion. Thus, the interaction between zein and 3T3 may be mediated with tTG. Based on this result, we also hypothesized zein substrates may be useful in capturing cancer cells. Results showed that zein films enhanced adhesion of MDA-MB-231 line cells. Tissue transglutaminase treatment on zein films further enhanced cell spreading and adhesion. Cell capture increased with incubation time. At short incubation times, cell capture increased with zein content in the coating film. Cell capture yield increased linearly with tTG concentration. This study provided supporting evidence for the development of a zein platform for CTCs capture