SUPPORTED CELL MIMETIC MONOLAYERS AND THEIR COMPATIBILITY - Advanced Biomaterials: Fundamentals, Processing, and Applications - page 661

20.4 CALCIFICATION STUDIES

To check the bioactive interaction with ions, calcifi cation studies from metastable
salt solution were done on modifi ed surfaces. Calcifi cation to the organized
organic-inorganic interface in biological systems has been reported. Apart from
the blood compatibility, calcifi cation studies also provide understanding of the
orientation and packing density of the supported monolayers. Figure 20.5(IV)
shows the calcifi cation to the polymer surfaces. The authors have found that the
overall calcifi cation to the modifi ed surfaces reduced signifi cantly with respect to
the PC alone.

20.5 PROTEIN INTERACTION STUDIES

The modifi ed surfaces are antifouling, as evident from Figure 20.5(III). The
adsorbed proteins onto these ordered monolayers form a gradient at the surface
by retaining the natural conformation and hinder further interaction with the
blood cells. On surfaces where the protein interaction to the surface is minimal,

Figure 20.5. AFM image of bilayer (I) : PC polymer surface modifi ed with (PTC : Chol : GalC)
(1 : 0.35 : 0.125). Platelet activation on to material surface (II) ; Bare Polymer substrates (A),
modifi ed with cell mimetic monolayer (II), Blood cell adhesion studies on lipid modifi ed
polymer surfaces, using washed cells. PC bare (A). PC modifi ed with, (PTC) (B), (PTC : Chol)
(1 : 0.7) (C), (PTC : Chol) (1 : 0.35) (D), (PTC : Chol : GalC) (1 : 0.35 : 0.125) (E). Densitometric diagram
of the protein adsorption-desorption studies on lipid modifi ed polymer surfaces (III) , using
mixture of proteins. X axis length in cm (maximum 6 cm), and Y axis absorbance (maximum
value = 0.5). Polymer bare (A). Polymer modifi ed with lipid bilayer containing albumin and
heparin (II), albumin heparin and polyethylene glycol (III). The peaks in fi gure-III are (1)
albumin, (2) γ globulin and (3) fi brinogen. Calcifi cation studies (IV) : Bare polymer substrate
(A). Polymer modifi ed with lipid bilayer which is anchored with albumin and heparin (B). Blood
cell adhesion studies on lipid modifi ed polymer surfaces (V) ; using washed cells. PC bare (A).
PC modifi ed with, (PTC) (B), (PTC : Chol) (1 : 0.7) (C), (PTC : Chol) (1 : 0.35) (D), (PTC : Chol : GalC)
(1 : 0.35 : 0.125) (E). Schematic representation of the proposed orientation of the deposited
mono and bilayers on hydrophobic PC polymer surface and their protein as well as blood
cell interaction (VI) ; Horizontally, PC bare (A), PC modifi ed with (PTC : Chol) (1 : 0.7) (B), PC
modifi ed with (PTC : Chol) (1 : 0.35) (C), PC modifi ed with (PTC : Chol : GalC) (1 : 0.35 : 0.125) (D).
Vertically, The unmodifi ed and modifi ed substrates (1) Protein adsorption to the substrates (2)
Cell adhesion to the substrates (3). PTC ( ), Chol ( ), GalC ( ), protein
( ), erythrocyte ( ), leukocyte ( ), Platelets ( ) (II). Schematic represen-
tation of Stabilized supported bilayer on polymeric substrate and osmotic exclusion of ions
proteins and blood cells from the modifi ed surface (VII) , Bare polymer (A), OCMC (D), polymer
modifi ed with OCMC-AH (B), OCMC-AHP (C), Albumin ( ), Heparin ( ), PEG ( ),

PC ( ), Chol ( ), GalCC ( ). Ions., (P) Proteins, (C) Blood cells (II).