Preperation Of Glycosylated Hyperbranched Polymers Modified Surfaces For Cell Migration

Cell migration, a coordinated multilevel process, plays a very important role in many key physiological and pathological events such as embryonic development, wound healing and metastasis. Carbohydrate is the major component in living organisms, and carbohydrate-protein interactions involve the binding of lectins, or carbohydrate recognition proteins, to specific saccharide ligands. It is an efficient way to fabricate glycosylated surfaces to modulate cell migration.In this work, a kind of glycosylated hyperbranched polymer (LA-HPMA) was synthesized, and grafted on glass slide through dopamine deposition with different densities adjusted by co-grafting of poly(ethylene glycol) (PEG). The LA-HPMA and PEG molecular brushes were characterized by X-ray photoelectron spectrometry (XPS), quartz crystal microbalance with dissipation (QCM-d) and ellipsometry. The adhesion of human hepatoma (HepG2) cells was improved on the surface of a higher LA-HPMA, and the migration rate was accelerated to 12.65 μm/h on 75% LA-HPMA surface, four times as that on TCPS surface. By contrast, the density and spreading area of mouse embryonic fibroblast (NIH3T3) cells was not significantly influenced by the LA-HPMA density, and the migration rate did not change significantly on all types of surfaces either. Therefore, the specific interactions of carbohydrate-protein can be used to modulate cell behaviors in vitro, for example the selective adhesion and migration of HepG2 cells.In order to investigate the influence of lactobionic acid gradient surface for HepG2 cell directional migration, we prepared a complementary density of LA-HPMA/PEG by immersing the glass slides into the PEG gradient solutions, and then be back filled in LA-HPMA solution. XPS was used to characterize the gradient surface by measuring the N/C ratio on different positions of the slides. LA-HPMA density increased along the gradient, while PEG density decreased.83.7% of HepG2 cells exhibited preferential orientation and enhanced directional migration behavior on the gradient surface at the position of 4 mm, and the fastest migration rate was 2.8 times as that on TCPS. As a comparison, NIH3T3 cells showed no significantly directional migration nor enhanced migration rate. The specific interaction between galactose and ASGPR expressed on HepG2 cell membrane is the major force to induce HepG2 cell directional migration over NIH3T3, a kind of ASGPR negative cell. The success of the complementary gradient depends on the appropriate interplay between the PEG and specific carbohydrate-protein interactions, enabling the selective guidance of HepG2 cell migration.