New Class of Ultrathin, Highly Cell-Adhesion-Resistant Polyelectrolyte Multilayers with Micropatterning Capabilities

Abstract

Hydrogen-bonded multilayers comprised of polyacrylamide (PAAm) and a weak polyelectrolyte, such as poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMA), were investigated for their surface-cell interactions. The assembled films were lightly cross-linked thermally or photochemically in order to render them stable in a physiological environment. Both PAA/PAAm and PMA/PAAm multilayers were found to exhibit a high resistance to the adhesion (cytophobicity) of mammalian fibroblasts, even with only a single bilayer coating. Protein adsorption to the multilayers, as revealed by surface plasmon resonance measurements, was greatly reduced for fibronectin and serum-containing medium. In situ swelling experiments indicate that the H-bonded multilayers are hydrogellike coatings capable of a high level of swelling in buffered solution. Utilizing the H-bonding nature of these multilayers, we were able to micropattern the films to create more complex cell-resistant/-adhesive surfaces. The long-term stability of the cell-resistant multilayers was found to be exceptionally good even under conditions (pH 7.4, buffered solution) where a high degree of swelling takes place. No degradation of the micropatterned films was observed over a period of a month, during which time the multilayer coatings remained highly resistant to cell-adhesion.

Biochemical Functionalization of Polymeric Cell Substrata Can Alter Mechanical Compliance

“…The unmodified PEM exhibits a nominal E (2.4 × 10 5 Pa), consistent with the high swelling capacity and low cross-linking density of this PEM, as well as with previous mechanical analysis of this polymer film. 2,14,26,34 The second step in the process of surface engineering involves the addition of PAH as a base for conjugation of RGD. This can be readily accomplished by adsorption of the polymer chain from a dilute solution of PAH or by polymer-on-polymer stamping as described by Berg et al 14 Samples prepared with PAH according to this stamping protocol exhibited a slightly lower mean E with respect to the unmodified PEM (1.6 × 10 5 Pa); this difference was found to be within the margin of error of the nanoindentation approach.…”

Synthesis and Characterization of Cationic and Anionic Cyclodextrin Oligomers and Their Use in Layer-by-Layer Film Formation

“…The multilayers fabricated by LbL process have been utilized in an enormous range of applications. 12,13,[19][20][21] Especially, water-soluble polymers having similar property as weak acid or weak base exhibit highly tunable surface properties as they are processed by LbL deposition technique. Therefore, we used LbL process for the ionic oligo (β-CyD)s to fabricate multilayer films.…”

“…[11][12][13] The previously reported polymeric CyDs have CyD as side groups or main chain of the polymer. The former method is mostly based on radical polymerization of acrylate derivatives of CyD or the monomers that form complexes with CyD.…”

Anti-thrombogenicity by Layer-by-Layer

“…Silicon wafers coated with the polyelectrolyte blend films were immersed for 20 min in phosphate buffered saline (PBS) containing 0.5 mg/ml fibrinogen, followed by rinsing with PBS (1 min) and N2 drying 20,21,22,23 . Fibrinogen was identified by the amide C-N-H vibrational bands of amide groups (CO-NH).…”