Construction of polyfunctional coatings assisted by gallic acid to facilitate co-immobilization of diverse biomolecules.

Designing a multifunctional surface based on the coimmobilization of two or more diverse biomolecules with synergic action is very important in certain cases. In this work, a facile method by two-step aimed to construct a polyfunctional coating containing -COOH, -NH2, and phenol/quinine groups was reported. The first-step was to introduce amine groups onto target modified-surface by coating with plasma polymerized allylamine (PPAam), followed by the second-step conjugation of gallic acid (3,4,5-trihydroxybenzoic acid) onto the PPAam surface. The density of -COOH, -NH2, and phenol/quinone groups could be regulated easily by adjusting the reaction time of GA conjugation, making it possible to coimmobilize two or three diverse molecules. This has been shown by the successful coimmobilization of anti-CD34 antibody and vascular endothelial growth factor (VEGF). The surface coimmobilized with the anti-CD34 antibody and VEGF presented significant enhancement in the capture of endothelial progenitor cells (EPCs) and the growth of human umbilical vein endothelial cells (HUVECs). These data suggest the huge potential of such polyfunctional coating for tailoring the desired interfacial properties of materials through selectively conjugating two or more diverse bioactive molecules with synergic action.