Polysaccharide-based nano-engineered multilayers for controlled cellular adhesion in label-free biosensors

Controlling cellular adhesion is a critical step in the development of biomaterials, and in cell- based biosensing assays. Usually, the adhesivity of cells is tuned by an appropriate biocompatible layer. Here, synthetic poly(diallyldimethylammonium chloride) (PDADMAC), natural chitosan, and heparin (existing in an extracellular matrix) were selected to assembly PDADMAC/heparin and chitosan/heparin films. The physicochemical properties of macroion multilayers were determined by streaming potential measurements (SPM), quartz crystal microbalance (QCM-D), and optical waveguide lightmode spectroscopy (OWLS). The topography of the wet films was imaged using atomic force microscopy (AFM). The adhesion of preosteoblastic cell line MC3T3-E1 on those well-characterized polysaccharide-based multilayers was evaluated using a resonant waveguide grating (RWG) based optical biosensor and digital holographic microscopy. The latter method was engaged to investigate long-term cellular behavior on the fabricated multilayers. (PDADMAC/heparin) films were proved to be the most effective in inducing cellular adhesion. The cell attachment to chitosan/heparin-based multilayers was negligible. It was found that efficient adhesion of the cells occurs onto homogeneous and rigid multilayers (PDADMAC/heparin), whereas the macroion films forming "sponge-like" structures (chitosan/heparin) are less effective, and could be employed when reduced adhesion is needed. Polysaccharide-based multilayers can be considered versatile systems for medical applications. One can postulate that the presented results are relevant not only for modeling studies but also for applied research.